Melatonin Side Effects and Safety 101

1. Drowsiness During Daytime

One of the most commonly reported side effects of melatonin supplements is residual drowsiness during the day. This phenomenon occurs when melatonin levels remain elevated after waking, leading to a lingering sense of sleepiness that can impair alertness and concentration. The sensation is often compared to the grogginess experienced after a restless or insufficient night’s sleep, making it challenging to focus on daily tasks or operate machinery safely. In some cases, this effect may be more pronounced in individuals who are particularly sensitive to melatonin or who take higher doses than recommended.

To minimize the risk of daytime drowsiness, it is important to pay careful attention to the timing and dosage of melatonin intake. Experts generally suggest taking melatonin supplements 30 minutes to one hour before bedtime to allow the hormone to align with the body’s natural circadian rhythms (Sleep Foundation). Avoiding late-night or middle-of-the-night doses can further reduce the chance of next-day fatigue. Consulting a healthcare provider for personalized dosing advice is also recommended, as individual responses can vary significantly.

2. Headaches

Headaches are another frequently cited side effect of melatonin supplementation. The onset of headaches is thought to be related to the hormone’s impact on neurotransmitter activity and blood flow within the brain. Melatonin influences the production and release of certain chemicals, including serotonin, which plays a key role in vascular regulation. These biochemical changes can lead to alterations in blood vessel dilation and constriction, sometimes resulting in tension or migraine-like headaches. This process bears resemblance to the headaches experienced during caffeine withdrawal, where abrupt changes in brain chemistry and circulation can trigger discomfort.

While mild headaches may resolve on their own as the body adjusts to melatonin, persistent or severe headaches should not be ignored. If headaches continue for several days or interfere with daily activities, it is advisable to consult a healthcare professional. Chronic or intense pain could signify an underlying issue or a sensitivity to melatonin supplementation. For further information on side effects and when to seek medical advice, refer to resources such as the Mayo Clinic’s melatonin guide. Early intervention can help identify safer alternatives or appropriate dosage adjustments tailored to individual needs.

3. Dizziness

Dizziness is a potential side effect of melatonin use, primarily because of its influence on blood pressure and the body’s sense of equilibrium. Melatonin can cause a modest reduction in blood pressure by relaxing blood vessels, which may lead to decreased blood flow to the brain, especially upon standing or changing positions quickly. This effect is similar to the transient lightheadedness some people feel when rising abruptly from a seated or lying position, a phenomenon known as orthostatic hypotension. For individuals already prone to low blood pressure or those taking antihypertensive medications, melatonin may intensify this sensation.

To reduce the risk of dizziness and prevent falls, it is advisable to rise slowly from bed or from a seated position, allowing the body time to adjust to changes in blood pressure. Keeping a sturdy chair or support nearby can also offer stability during moments of imbalance. Older adults and those with mobility challenges should exercise particular caution, as dizziness can increase the risk of injury from falls. If dizziness persists or worsens, consult a healthcare provider for personalized guidance. For more details on melatonin’s cardiovascular effects, visit the National Institutes of Health research article.

4. Nausea

Nausea is another side effect that some users experience when taking melatonin supplements. This reaction is largely due to the way melatonin interacts with the gastrointestinal system. The hormone can influence the movement of the digestive tract and alter the secretion of certain digestive enzymes, potentially causing mild stomach discomfort or queasiness. Similar to gastrointestinal reactions seen when starting new vitamins or supplements, the body may need time to adjust to the presence of additional melatonin, especially in higher dosages or in individuals with sensitive digestive systems.

If nausea occurs after melatonin intake, a practical strategy is to take the supplement with a small amount of food. Consuming melatonin alongside a light snack can buffer the stomach lining and reduce the likelihood of irritation, much like how people often take iron or other supplements with food to avoid stomach upset. It is also advisable to start with the lowest effective dose and gradually increase only if needed. Persistent or severe nausea should prompt a discussion with a healthcare provider to rule out other causes. For more information on gastrointestinal side effects and management, refer to Medical News Today’s melatonin overview.

5. Vivid Dreams or Nightmares

Melatonin’s influence on sleep architecture is well-documented, particularly its enhancement of REM (rapid eye movement) sleep—the stage of sleep most closely associated with dreaming. By increasing the proportion and intensity of REM sleep, melatonin can lead to more frequent, vivid, or emotionally charged dreams, and in some cases, nightmares. This effect is comparable to what some individuals experience when taking certain antidepressant medications, such as selective serotonin reuptake inhibitors (SSRIs), which are also known to alter REM sleep dynamics and intensify dream activity. For some, these vivid dreams may be fascinating or even enjoyable; however, others may find them distressing or disruptive to their overall sleep quality.

If intense dreams or nightmares become a regular occurrence and interfere with restful sleep, several strategies may help. Reducing the melatonin dose, taking the supplement earlier in the evening, or considering a temporary break from melatonin can often minimize these effects. Keeping a sleep journal to track patterns and discussing troublesome dreams with a healthcare professional may also provide insight and solutions tailored to individual needs. For additional details on melatonin’s impact on sleep stages and dreaming, visit the Sleep Foundation’s guide to melatonin and dreams.

6. Depression Symptoms

Melatonin supplementation can influence mood by altering the balance of neurotransmitters such as serotonin and dopamine, which play critical roles in emotional regulation. These biochemical shifts may, in rare cases, lead to the emergence or worsening of depression symptoms, such as persistent sadness, low motivation, or social withdrawal. This phenomenon is somewhat analogous to the mood changes observed in seasonal affective disorder (SAD), where changes in light exposure and subsequent melatonin production are believed to contribute to depressive episodes, particularly during darker winter months. While melatonin is often marketed as a benign sleep aid, its impact on mental health should not be underestimated, especially for those with a history of mood disorders.

If you notice a downturn in mood, increased irritability, or other symptoms of depression after starting melatonin, it is important to promptly consult a mental health professional or primary care provider. Early intervention can prevent symptoms from worsening and provide access to alternative sleep strategies or therapies. For more information on melatonin’s effects on mood and mental health, refer to the Cleveland Clinic’s melatonin fact sheet. Remember, any significant change in emotional well-being warrants professional attention and support.

7. Irritability

Irritability is another potential side effect associated with melatonin supplementation, stemming from its influence on the body’s hormone balance and neurotransmitter activity. Melatonin’s modulation of the sleep-wake cycle can create downstream effects on cortisol and serotonin, both of which are closely tied to mood regulation. As these biochemical changes take place, some individuals may experience mood swings or increased sensitivity to stress—symptoms reminiscent of the irritability seen in premenstrual syndrome (PMS) or during periods of heightened emotional strain. This can manifest as impatience, frustration over minor inconveniences, or difficulty managing daily stressors.

It is important to monitor for new or worsening behavioral changes after beginning melatonin, especially if you notice a pattern of heightened irritability that was not present before. Keeping a daily mood journal can help identify trends or triggers related to melatonin use. If irritability persists or negatively impacts relationships and daily functioning, consider consulting a healthcare provider for guidance on adjusting the dose or exploring other sleep aids. For more information on melatonin’s psychological effects, review the Healthline article on melatonin side effects. Early recognition and action can help ensure safe and effective management of sleep and mood.

8. Hormonal Effects in Children

Melatonin supplementation in children has raised concerns among healthcare professionals due to its potential impact on hormonal development, particularly the timing of puberty. Melatonin regulates not only sleep but also influences reproductive hormones. Several case studies and reviews have suggested that long-term melatonin use may delay the onset of puberty by interfering with the hypothalamic-pituitary-gonadal axis, which controls the release of hormones necessary for sexual maturation. While the exact risk remains unclear, a 2015 review in the International Journal of Endocrinology highlighted instances of delayed pubertal progression in children who used melatonin regularly.

Given these possible effects, parents should exercise caution when considering melatonin for their children, especially for extended periods. It is crucial to consult a pediatrician or sleep specialist before starting melatonin to thoroughly weigh the risks and benefits and to explore alternative behavioral or environmental interventions for sleep difficulties. For further guidance, the New York Times offers an overview of current research and expert opinions on melatonin use in children. Prioritizing professional advice helps ensure the safety and healthy development of young individuals.

9. Changes in Blood Pressure

Melatonin has a notable effect on cardiovascular function, particularly in its capacity to lower blood pressure. The hormone induces vasodilation, or the widening of blood vessels, which can lead to a decrease in both systolic and diastolic blood pressure. This action is somewhat similar to the way anti-hypertensive medications work, albeit usually to a milder degree. For individuals with normal or low baseline blood pressure, melatonin’s influence might result in lightheadedness or dizziness, especially upon standing or during physical activity. In patients already taking blood pressure medications, there is a risk of an additive effect, potentially causing blood pressure to drop too low.

People with preexisting heart conditions or those managing hypertension should be especially cautious when considering melatonin supplements. It is essential to consult a healthcare provider to discuss potential interactions and to determine an appropriate dosage. Regular monitoring of blood pressure is advised for anyone starting melatonin, particularly if they notice new symptoms such as dizziness or fatigue. For more comprehensive information on melatonin and cardiovascular health, the National Institutes of Health provides an in-depth review. Personalized medical guidance ensures safe and effective management of both sleep and heart health.

10. Allergic Reactions

Although rare, allergic reactions to melatonin supplements can occur and may trigger a variety of immune responses. Symptoms can range from mild to severe and typically include skin rashes, itching, swelling (particularly of the face, tongue, or throat), hives, and sometimes respiratory difficulties such as wheezing or shortness of breath. These reactions are similar to allergies experienced with other dietary supplements, where the body’s immune system mistakenly identifies an ingredient as harmful and mounts a protective response. Fillers, binders, or other inactive ingredients in melatonin products may also contribute to allergic symptoms in sensitive individuals.

If you notice mild symptoms like itching or localized rash after taking melatonin, discontinue use and consult a healthcare provider for advice. However, if you experience severe reactions—such as swelling of the lips or throat, difficulty breathing, or a sudden drop in blood pressure (anaphylaxis)—seek emergency medical care immediately, as these can be life-threatening. For a detailed overview of supplement allergies and their management, visit the WebMD slideshow on allergy-causing supplements. Prompt recognition and response are crucial for minimizing the risks associated with allergic reactions to melatonin.

11. Stomach Cramps

Stomach cramps are a reported side effect among some melatonin users, typically stemming from irritation of the digestive tract. Melatonin can influence gut motility and interact with receptors in the gastrointestinal system, occasionally leading to spasms or discomfort. This type of cramping is similar to what some people experience when starting new medications or supplements, such as iron or certain antibiotics, which can also cause the digestive muscles to contract irregularly. Symptoms may range from mild, fleeting twinges to more persistent or painful spasms, depending on individual sensitivity and dosage.

To help manage or prevent stomach cramps, consider taking melatonin with a small amount of food, as this can buffer the stomach lining and ease the hormone’s passage through the digestive tract. Staying well-hydrated and choosing a lower dose may also reduce the likelihood of gastrointestinal side effects. If cramps persist or significantly interfere with comfort, it is advisable to consult a healthcare provider, as continued discomfort may indicate a need for dosage adjustment or alternative sleep aids. For more information on digestive side effects from melatonin and best practices for supplement use, refer to the Medical News Today melatonin guide.

12. Short-Term Memory Issues

Melatonin’s effect on cognitive processes—including short-term memory—has been noted in some users, particularly when taken in higher doses or over extended periods. Melatonin acts on receptors in the brain that regulate not only sleep but also aspects of cognitive performance. In some cases, individuals may experience moments of forgetfulness, trouble recalling recent events, or mild confusion, symptoms often described as “brain fog.” This sensation is comparable to the mental cloudiness that results from insufficient or disrupted sleep, where the brain struggles to efficiently process and store information.

If you notice changes in memory or cognitive sharpness after starting melatonin, it may be a sign that the dosage is too high or that your body is particularly sensitive to the supplement. Lowering the dose or taking melatonin less frequently can often resolve mild cognitive effects. Persistent or worsening memory issues warrant a conversation with a healthcare provider, as they could signal an underlying medical condition or the need for an alternative sleep strategy. For an overview of melatonin’s neurological effects and safe supplement use, consult the Sleep Foundation’s melatonin side effects guide. Personalizing your approach helps ensure optimal sleep without compromising mental clarity.

13. Reduced Alertness for Driving

Melatonin’s sedative properties, which promote sleepiness and relaxation, can also impair coordination and slow reaction times—effects that are particularly concerning when it comes to activities requiring full alertness, such as driving. Studies have shown that melatonin can delay cognitive processing and decrease physical responsiveness for several hours after ingestion. This influence is comparable to the drowsiness and slowed reflexes induced by certain prescription sleep aids or sedative medications, which are known to compromise driving safety. Individuals may underestimate the residual effects of melatonin, mistakenly believing it wears off immediately upon waking.

To minimize the risk of accidents, it is crucial not to drive or operate heavy machinery soon after taking melatonin, especially if you feel groggy or less attentive. Ideally, melatonin should be taken only when you are ready to sleep and have at least seven to eight hours before you need to be fully alert. If you experience morning drowsiness or difficulty focusing, consider adjusting the timing or dosage of your supplement. For additional safety tips and research on melatonin and driving, refer to the Sleep Foundation’s melatonin safety recommendations. Prioritizing safety can prevent potentially hazardous situations on the road.

14. Lowered Body Temperature

Melatonin plays a significant role in regulating the body’s core temperature as part of its mechanism for preparing the body for sleep. After melatonin is released (or ingested as a supplement), it triggers a natural decrease in body temperature, which signals to the body that it is time to rest. Some individuals may notice a pronounced drop in temperature, leading to sensations of coolness or chills. This experience is similar to feeling cold after taking certain cold or flu medicines, which can also affect the body’s thermoregulatory processes. While a mild decrease in body heat is normal and can aid the onset of sleep, some people may find the effect uncomfortable, especially in colder environments.

If you experience chills or a noticeable drop in body temperature after taking melatonin, consider layering clothing or using extra blankets at bedtime to maintain comfort. Adjusting the room temperature or wearing warm socks can also help offset the sensation of being cold. For more details on melatonin’s influence on thermoregulation and practical ways to manage temperature changes, visit the Sleep Foundation’s guide to melatonin side effects. Simple adjustments can help you stay comfortable and enjoy the benefits of restful sleep.

15. Unusual Bleeding

Although uncommon, melatonin has been associated with altered blood clotting in rare cases, leading to unusual bleeding or bruising. This effect is thought to be due to melatonin’s interaction with the coagulation cascade and platelet function, potentially reducing the blood’s ability to clot efficiently. Several case studies, including those summarized in the National Institutes of Health review, have reported instances of increased bleeding tendencies in individuals taking melatonin, especially when combined with other medications that affect blood clotting, such as anticoagulants or antiplatelet drugs.

People taking blood thinners like warfarin, aspirin, or clopidogrel should exercise caution with melatonin supplementation, as the risk of bleeding complications may be elevated. Warning signs can include frequent nosebleeds, unusual bruising, blood in urine or stool, or prolonged bleeding from minor cuts. If any of these symptoms occur, it is important to seek medical attention promptly and inform your healthcare provider about all supplements and medications you are using. For further reading on melatonin’s effect on bleeding and safety considerations for those on anticoagulants, consult the Mayo Clinic’s melatonin overview.

16. Influence on Seizure Threshold

Melatonin’s effects on neural excitability have raised concerns about its potential to lower the seizure threshold, particularly in individuals with a history of epilepsy or seizure disorders. By modulating neurotransmitter activity in the brain, melatonin may, in rare cases, increase the likelihood of seizure activity—an effect observed with some other medications, including certain antidepressants and antipsychotics. While there is ongoing debate in the scientific community regarding melatonin’s exact impact on seizure risk, several case reports and reviews, such as those discussed in the National Institutes of Health article, have documented seizures coinciding with melatonin use, especially at higher doses or in sensitive populations.

Because of this potential risk, individuals with epilepsy or other seizure disorders should consult a neurologist or epilepsy specialist before beginning melatonin supplementation. Close monitoring and professional guidance are essential to ensure that sleep management strategies do not inadvertently increase seizure frequency or severity. Any new or unusual neurological symptoms should be reported immediately. For further information on melatonin’s neurological effects and recommendations for those with epilepsy, refer to the Epilepsy Foundation’s melatonin resource. Personalized medical advice is key to balancing sleep benefits with neurological safety.

17. Drug Interactions

Melatonin can interact with a variety of medications, sometimes altering their effectiveness or increasing the risk of side effects. Notably, melatonin may enhance the effects of anticoagulants like warfarin and clopidogrel, raising the risk of bleeding. It can also amplify the blood pressure-lowering action of antihypertensive drugs, potentially leading to hypotension and dizziness. In addition, melatonin may interact with immunosuppressants, diabetes medications, anticonvulsants, and certain antidepressants, occasionally intensifying sedative effects or impacting blood sugar and seizure control. Even common over-the-counter drugs, such as benzodiazepines or nonsteroidal anti-inflammatory drugs (NSAIDs), can be affected by melatonin’s presence in the body.

Given these possible interactions, it is essential to review all current medications, supplements, and herbal products with a pharmacist or healthcare provider before starting melatonin. This review helps identify potential conflicts and ensures that your overall treatment plan remains safe and effective. For a comprehensive list of drug interactions and guidance on melatonin use, visit the Drugs.com melatonin interactions page. Proactive communication with your healthcare team can minimize risks and optimize both sleep quality and medication safety.

18. Hormonal Effects in Adults

Melatonin’s influence extends beyond sleep regulation to the broader endocrine system, where it can impact reproductive hormones in adults. Research indicates that melatonin may affect levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), both of which are critical for fertility and reproductive health. This hormonal modulation is somewhat analogous to the way oral contraceptives alter hormonal balance to prevent ovulation, although melatonin’s effects are generally subtler and less predictable. In some cases, high or prolonged melatonin use has been linked to changes in menstrual cycles, libido, or testosterone levels, though evidence remains mixed and more studies are needed.

Adults who are planning to conceive or undergoing fertility treatments should consult with a healthcare provider before starting melatonin supplementation, as hormonal shifts could potentially impact ovulation or sperm production. Open discussion with a doctor is especially important for those with preexisting hormonal disorders or those taking hormone-regulating medications. For additional insights into melatonin’s hormonal effects and fertility considerations, refer to the National Institutes of Health review on melatonin. Personalized guidance helps ensure that supplement use aligns with reproductive goals and overall hormonal health.

19. Liver Function Impact

Melatonin is primarily metabolized by the liver, where specialized enzymes break it down before it is excreted from the body. This metabolic process is similar to that of acetaminophen (Tylenol), which also relies on liver enzymes for safe elimination. When liver function is compromised—due to conditions such as hepatitis, cirrhosis, or fatty liver disease—the breakdown and clearance of melatonin can be significantly slowed. As a result, melatonin levels may accumulate in the body, increasing the risk of side effects and toxicity. Symptoms could include excessive drowsiness, confusion, or exacerbation of existing liver-related issues.

Individuals with diagnosed liver disease or reduced liver function should use melatonin with caution and always under the supervision of a healthcare professional. Dose adjustments or alternative sleep aids might be necessary to avoid potential complications. Regular monitoring of liver enzymes and overall health is strongly recommended for those in this group. For more detailed information on melatonin metabolism and liver safety, consult the National Center for Biotechnology Information’s LiverTox database. Informed decision-making and close medical oversight can help mitigate risks for those with compromised liver function.

20. Night Sweats

Melatonin’s regulatory effects on the body’s circadian rhythms extend to various physiological systems, including the autonomic nervous system, which influences sweat gland activity. Some users report experiencing night sweats after taking melatonin, possibly due to fluctuations in body temperature and hormonal signaling during sleep. This phenomenon can feel similar to the night sweats many individuals encounter during menopause, which are triggered by shifting hormone levels and changes in thermoregulation. Although the exact mechanism is not fully understood, melatonin may indirectly activate sweat glands as part of its role in lowering core body temperature and preparing the body for rest.

If you notice increased sweating or awaken with damp sheets after starting melatonin, consider adjusting your sleepwear or bedding. Opting for lightweight, moisture-wicking fabrics and using breathable sheets can help alleviate discomfort and improve sleep quality. Lowering bedroom temperature or using a fan may also make a difference. Should night sweats persist or significantly disrupt sleep, speak with a healthcare provider to review your melatonin dosage and rule out other causes. For further reading on melatonin’s side effects, including night sweats, visit the Sleep Foundation’s melatonin guide.

21. Sleepwalking

Melatonin’s impact on the sleep cycle involves not only REM (rapid eye movement) sleep, but also non-REM stages, where sleepwalking most commonly occurs. By altering the natural balance and depth of these sleep phases, melatonin may increase the likelihood of parasomnias such as sleepwalking, particularly in individuals already predisposed to these behaviors. Similar effects have been observed with certain prescription sleep aids like zolpidem (Ambien), which are known to trigger complex sleep-related activities, including walking, eating, or even driving while only partially awake. While melatonin-induced sleepwalking episodes are generally rare, they can pose significant safety risks in the home environment.

If sleepwalking or other unusual nighttime behaviors begin after starting melatonin, it is important to implement safety measures. Secure doors and windows, remove tripping hazards, and alert household members to the potential for nighttime wandering. Keeping a sleep diary may help identify patterns or triggers, and consulting a sleep specialist can provide tailored solutions or alternative therapies. For additional guidance on sleepwalking and its association with melatonin and other sleep aids, refer to the Sleep Foundation’s resource on sleepwalking. Early recognition and intervention can help ensure the safety and well-being of those affected.

22. Daytime Fatigue

Daytime fatigue is a commonly reported issue among melatonin users, often resulting from lingering hormone levels that extend into waking hours. When melatonin remains active in the bloodstream after morning wake-up, it can suppress alertness and contribute to feelings of sluggishness or low energy. This state of fatigue closely resembles the sensation experienced during jet lag, when the body’s internal clock is misaligned with external cues, causing mismatched peaks of wakefulness and sleepiness. Individuals may struggle to concentrate, experience reduced motivation, or feel the need for excessive napping, which can further disrupt the natural sleep-wake cycle.

To minimize daytime fatigue, it is important to fine-tune both the timing and dosage of melatonin supplementation. Experts recommend taking melatonin about 30 minutes to one hour before bedtime and starting with the lowest effective dose. Adjusting the time of ingestion so that the hormone’s effects taper off by morning can help restore normal daytime energy levels. If fatigue persists, consult a healthcare provider to explore alternative sleep strategies or to rule out underlying sleep disorders. For further reading and dosage tips, see the Sleep Foundation’s melatonin dosing guide.

23. Decreased Libido

Melatonin’s role as a hormonal modulator means it can sometimes impact sexual health, including libido. The hormone influences the secretion of reproductive hormones such as testosterone and estrogen, which play key roles in maintaining sexual desire and function. In certain individuals, regular melatonin supplementation may lead to a noticeable reduction in libido, echoing effects seen with selective serotonin reuptake inhibitors (SSRIs)—a class of antidepressants known to dampen sexual desire through their influence on neurotransmitters and hormonal pathways. While the effect is not universal, some people may experience less interest in sexual activity or subtle changes in sexual response.

If you begin to notice changes in your libido after starting melatonin, consider keeping a journal to track sexual health and any related symptoms. Monitoring these changes can help determine whether melatonin is the likely cause or if other factors may be involved. Should decreased libido persist or negatively impact quality of life, discuss your concerns with a healthcare provider for personalized advice or alternative strategies. For more insights on melatonin’s hormonal effects and sexual health, refer to the NIH’s melatonin review. Open communication and self-awareness are essential for maintaining both sleep and sexual well-being.

24. Weight Changes

Melatonin may influence body weight through its effects on metabolism, appetite regulation, and sleep quality. Some studies suggest that melatonin can modestly impact metabolic rate, insulin sensitivity, and even fat storage, though results are mixed and long-term data remain limited. These effects may be indirect, as improving sleep quality with melatonin could help prevent the weight gain commonly associated with chronic sleep deprivation, which disrupts hunger hormones like leptin and ghrelin. Conversely, in rare cases, users have reported unintended weight loss or gain during periods of prolonged melatonin use, possibly due to changes in appetite or altered energy expenditure.

If you are using melatonin over an extended period, consider monitoring your weight and noting any significant fluctuations. Maintaining a balanced diet and regular exercise routine can help offset any minor metabolic changes induced by the supplement. Should you observe persistent, unexplained weight changes, consult a healthcare professional to assess whether melatonin or another underlying factor may be responsible. For more on melatonin’s potential influence on metabolism and weight, see the NIH’s comprehensive review on melatonin. Awareness and regular monitoring are key to maintaining overall health while using sleep aids.

25. Digestive Problems

Melatonin can affect the digestive system by altering gut motility—the movement of food and waste through the gastrointestinal tract. Some users report symptoms such as bloating, diarrhea, constipation, or abdominal discomfort after starting melatonin, likely due to the hormone’s influence on the enteric nervous system. These digestive issues are comparable to the side effects sometimes experienced with magnesium supplements, which also modulate muscle contractions in the gut and can disrupt normal bowel patterns in sensitive individuals. While most symptoms are mild and short-lived, they can be bothersome for those with preexisting digestive sensitivities.

To support gentle digestion while using melatonin, consider taking the supplement with a small, bland snack to minimize irritation. Staying well-hydrated, maintaining a fiber-rich diet, and engaging in light physical activity can promote healthy gut function. If digestive discomfort persists or worsens, it may be necessary to lower the dose or take a break from melatonin to allow the gastrointestinal system to recover. For further information on digestive side effects and best practices, refer to the Healthline overview of melatonin side effects. Listening to your body and responding promptly to symptoms can help ensure a more comfortable experience with supplementation.

26. Dry Mouth

Dry mouth, or xerostomia, is a side effect that some people experience when taking melatonin. This sensation results from reduced saliva production, which may occur as melatonin interacts with receptors in the salivary glands or modulates the autonomic nervous system’s control over fluid secretion. The effect is similar to that caused by antihistamines, which are well-known for leaving users with a parched, sticky feeling in the mouth. While generally mild, dry mouth can lead to discomfort, increased thirst, difficulty swallowing, or a higher risk of dental problems if it persists over time.

To combat dry mouth while using melatonin, it’s helpful to stay well-hydrated throughout the day and keep a glass of water by your bedside at night. Chewing sugar-free gum or sucking on sugar-free lozenges can stimulate saliva production and provide temporary relief. Maintaining good oral hygiene and considering a humidifier in your bedroom may also ease symptoms. If dry mouth remains bothersome or is accompanied by other side effects, consult a healthcare provider for further recommendations. For more information on managing dry mouth and melatonin side effects, visit the Healthline guide to melatonin side effects.

27. Anxiety Symptoms

While melatonin is generally used to promote relaxation and sleep, some individuals experience paradoxical anxiety symptoms after taking the supplement. This counterintuitive effect may be due to melatonin’s influence on neurotransmitter balances, particularly its interaction with serotonin and gamma-aminobutyric acid (GABA) pathways, which are crucial for regulating mood and anxiety levels. Much like how caffeine can unexpectedly trigger anxiety by overstimulating the nervous system, melatonin may, in rare cases, heighten feelings of restlessness, nervousness, or unease instead of calming the mind. These symptoms can manifest as racing thoughts, a sense of impending doom, or even physical signs such as a rapid heartbeat.

If you notice new or intensified anxiety after starting melatonin, it’s important to monitor your symptoms and consider lowering your dose or discontinuing use. Practicing relaxation techniques, such as deep breathing or meditation, may help alleviate mild anxiety. However, if anxiety becomes overwhelming, disruptive, or is accompanied by panic attacks or insomnia, seek support from a healthcare provider or mental health professional. For an in-depth discussion of melatonin’s potential to cause or worsen anxiety, see the Healthline article on melatonin side effects. Early intervention can ensure both safe sleep support and emotional well-being.

28. Skin Rash

Skin rash is a possible, though rare, allergic reaction associated with melatonin use. These rashes typically present as red, itchy, or raised patches on the skin and may develop shortly after starting supplementation. Such reactions can occur due to sensitivity to melatonin itself or to inactive ingredients and fillers found in some commercial preparations. The appearance and discomfort are similar to skin rashes that may arise from other dietary supplements, where the immune system reacts to perceived foreign substances introduced into the body. In most cases, the rash is mild, but it can become more pronounced or spread if supplementation continues.

If you develop a rash after taking melatonin, it is advisable to discontinue use immediately and monitor your symptoms. Applying a cool compress or over-the-counter hydrocortisone cream may provide temporary relief for mild cases. Should the rash persist, worsen, or be accompanied by other signs of an allergic reaction—such as swelling or difficulty breathing—seek medical attention promptly. For more information on supplement-induced skin rashes and when to seek help, consult the WebMD slideshow on allergy-causing supplements. Prompt action helps prevent escalation and ensures your safety while using supplements.

29. Hair Loss

While not commonly recognized as a side effect, there have been rare reports of hair thinning or loss in individuals using melatonin supplements. Melatonin’s influence on hormone levels, particularly those related to the hair growth cycle, may play a role in these cases. The phenomenon is somewhat similar to hormone-induced hair loss seen with fluctuations in thyroid hormones, sex hormones, or during periods of significant stress. Since melatonin can modulate the production of other hormones and interact with the body’s circadian rhythms, it’s possible that long-term or high-dose use could disrupt the natural cycle of hair growth and shedding in sensitive individuals.

If you notice increased hair shedding or thinning after starting melatonin, consider documenting these changes and discussing them with your healthcare provider, especially if you are using the supplement long-term. Monitoring your hair health can help determine whether melatonin or another underlying factor is contributing to the change. In most cases, discontinuing melatonin leads to gradual improvement if the supplement was the cause. For additional information on the relationship between supplements and hair loss, review the Healthline guide to supplements and hair loss. Open communication with your provider ensures effective management of both sleep and hair health.

30. Altered Menstrual Cycles

Melatonin’s regulatory effects on the endocrine system extend to reproductive hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which play critical roles in the menstrual cycle. By influencing the secretion of these hormones, melatonin may cause changes in menstrual regularity, flow, or cycle length for some women. These effects can be similar to those observed with stress-induced hormonal changes, where physical or emotional stressors disrupt the normal hormonal feedback loops and cause periods to become irregular, lighter, or even temporarily absent. Although many women will not notice significant shifts, those who are particularly sensitive to hormonal fluctuations may experience noticeable changes.

If you begin using melatonin and observe alterations in your menstrual cycle, it is advisable to track your periods using a calendar or a menstrual tracking app. Monitoring these changes can help you and your healthcare provider determine whether melatonin is contributing to the irregularity or if other factors may be involved. Should irregular cycles persist, or if you have concerns about fertility or reproductive health, consult a medical professional for personalized advice. For more information on how supplements and hormonal changes can affect menstruation, see the Healthline resource on menstruation and supplements.

31. Muscle Pain

Some individuals report experiencing muscle pain or aches after starting melatonin supplementation. While this side effect is relatively uncommon, it may arise due to melatonin’s influence on inflammation, electrolyte balance, or muscle metabolism. The discomfort is often described as a dull or persistent ache, sometimes accompanied by stiffness, and can be reminiscent of the muscle pain experienced by some people who take statins, a class of cholesterol-lowering medications known for causing myalgia as a side effect. Although the precise mechanism behind melatonin-induced muscle pain is not fully understood, it may be related to subtle shifts in hormone levels or inflammatory pathways.

If you notice new or worsening muscle pain after initiating melatonin, consider reducing your dose or pausing supplementation to see if symptoms improve. Gentle stretching, staying hydrated, and ensuring adequate intake of electrolytes such as magnesium and potassium may help manage discomfort. Should the pain persist, worsen, or interfere with daily activities, consult a healthcare provider to rule out other causes and discuss alternative sleep aids if needed. For further reading on muscle pain related to supplement use, visit the Healthline guide to myalgia. Listening to your body and seeking timely advice can help maintain overall well-being while addressing sleep concerns.

32. Chest Pain

Although melatonin is generally considered safe for heart health, there have been rare reports of chest pain or discomfort following its use. The exact cause is not well understood, but it may be related to melatonin’s effects on blood pressure regulation, changes in heart rate, or its interaction with other cardiovascular medications. In some cases, chest pain may be a result of heightened anxiety or panic, which can produce symptoms similar to those of a cardiac event. This overlap makes it difficult to distinguish between benign anxiety-induced chest pain and more serious cardiovascular issues.

Any new, persistent, or severe chest pain should be treated as a potential emergency, especially if accompanied by symptoms such as shortness of breath, dizziness, sweating, or pain radiating to the arm or jaw. Immediate medical evaluation is essential to rule out heart attack or other serious conditions. Do not ignore chest discomfort or attribute it solely to supplementation without consulting a professional. For more information on cardiovascular side effects and when to seek care, refer to the Mayo Clinic’s guide to heart attack symptoms. Prompt attention can be life-saving and ensures your safety when using melatonin or any supplement.

33. Palpitations

Melatonin can occasionally cause changes in heart rhythm, resulting in palpitations or a noticeable awareness of the heartbeat. These sensations may include rapid, fluttering, or pounding heartbeats, which can be unsettling but are often benign in healthy individuals. The experience is similar to palpitations triggered by caffeine intake, where stimulatory effects on the autonomic nervous system lead to temporary irregularities in heart rhythm. While melatonin is not a stimulant, its influence on blood pressure and the body’s circadian system may indirectly affect cardiac electrical activity, especially in those with underlying heart conditions or heightened sensitivity to supplements.

If you experience palpitations after taking melatonin, consider monitoring your heart rate and rhythm, particularly in the hours following each dose. Reducing the dosage or switching to a different sleep aid may help if palpitations are frequent or bothersome. It’s also wise to avoid combining melatonin with other substances that can affect heart rhythm, such as caffeine or certain medications. If palpitations persist, worsen, or are accompanied by chest pain, dizziness, or fainting, consult a healthcare provider promptly. For more details on palpitations and supplement use, visit the Healthline overview of palpitations. Careful self-monitoring can help ensure safety when using melatonin.

34. Vision Changes

Some rare reports suggest that melatonin use may cause vision changes, such as blurred vision, difficulty focusing, or increased sensitivity to light. These symptoms may stem from melatonin’s potential effect on intraocular pressure—the pressure within the eye—which, when altered, can impact visual clarity. This side effect is reminiscent of the blurry vision some people experience when taking antihistamines, which can affect the eye’s ability to produce adequate moisture or alter its pressure. Although vision changes with melatonin are uncommon, they may be more likely in individuals with preexisting eye conditions such as glaucoma or dry eye syndrome.

If you notice any vision disturbances after starting melatonin, discontinue use and schedule an evaluation with an eye care professional. Regular eye exams are especially important for anyone with a history of eye disease or those taking medications known to influence eye health. Early detection of changes in vision or eye pressure can prevent long-term complications. For more information on eye health and medications that may affect vision, refer to the American Academy of Ophthalmology’s guide to medication side effects. Staying vigilant and proactive can help ensure both safe supplementation and optimal visual health.

35. Tinnitus

Tinnitus, or ringing in the ears, has been rarely reported by some individuals using melatonin supplements. The exact cause is not well understood, but it’s possible that melatonin’s effects on neurotransmitter levels and blood flow within the auditory system could contribute to this symptom. This experience is similar to tinnitus triggered by certain medications, such as high doses of aspirin or some antibiotics, which can alter auditory nerve function or inner ear blood supply. While most cases of melatonin-associated tinnitus are mild and transient, the symptom can be bothersome or concerning, especially for those already prone to ear-related conditions.

If you develop ringing, buzzing, or other unusual sounds in your ears after starting melatonin, consider stopping the supplement to see if symptoms improve. Avoiding loud noises, reducing caffeine and salt intake, and practicing stress-reduction techniques may help ease tinnitus. If the ringing persists for more than a few days, worsens, or is accompanied by hearing loss or dizziness, consult an audiologist or healthcare provider for a thorough evaluation. For more information on tinnitus and its potential links to medications and supplements, visit the American Tinnitus Association’s causes of tinnitus page. Prompt attention can help identify underlying issues and guide appropriate management.

36. Swelling (Edema)

Swelling, or edema, is a rare but possible side effect reported by some melatonin users. Edema typically occurs when excess fluid accumulates in the body’s tissues, often in the ankles, feet, or hands. Melatonin may influence fluid balance by altering kidney function, vascular permeability, or the hormonal regulation of salt and water retention. This side effect is similar to the peripheral swelling experienced with certain blood pressure medications, such as calcium channel blockers, which can cause noticeable puffiness in the lower extremities. While melatonin-induced edema is uncommon, it can signal an underlying sensitivity or interaction with other medications.

If you notice new or unexplained swelling while taking melatonin—especially if it is persistent, severe, or accompanied by shortness of breath or weight gain—it’s important to seek medical evaluation. Documenting when the swelling began and any other changes in your medications or health can help your healthcare provider determine the cause. Stopping melatonin may resolve minor edema, but professional guidance is crucial to rule out more serious conditions such as heart, liver, or kidney problems. For more on drug-induced edema and management strategies, review the Healthline guide to edema. Prompt attention ensures your safety while using supplements.

37. Frequent Urination

Frequent urination is an occasional side effect noticed by some melatonin users, particularly when the supplement is taken close to bedtime. Melatonin may influence the body’s circadian regulation of kidney function and urine production, leading to increased nighttime trips to the bathroom. This effect is somewhat similar to the diuretic impact of caffeine, which stimulates the kidneys to produce more urine. Although melatonin is not a diuretic, its role in modulating hormonal and bodily rhythms can disrupt the usual nighttime suppression of urine output, known as nocturnal enuresis, causing sleep interruptions.

To minimize frequent urination associated with melatonin, consider adjusting the timing of your dose—taking it earlier in the evening rather than right before bed. Also, limit fluid intake in the hours leading up to sleep. If nighttime bathroom visits become disruptive or are accompanied by other urinary symptoms, consult a healthcare provider to rule out underlying urinary tract or prostate issues. For more information on how supplements may affect urinary habits and sleep, see the Sleep Foundation’s guide to melatonin and sleep. Small adjustments in routine can help preserve sleep quality and overall comfort during the night.

38. Constipation

Constipation is a possible, though less common, side effect of melatonin supplementation. Melatonin can slow gut motility by interacting with receptors in the gastrointestinal tract and influencing the enteric nervous system. This reduction in the movement of the intestines may lead to infrequent, hard, or difficult-to-pass stools. The experience is similar to the constipation that some individuals encounter when taking calcium supplements, which also affect muscle contraction in the digestive tract and can reduce transit time. While not everyone will be affected, those with preexisting digestive sensitivities may be more prone to constipation with melatonin use.

To help prevent constipation, maintain adequate hydration, consume a fiber-rich diet including fruits, vegetables, and whole grains, and engage in regular physical activity. Establishing a consistent bathroom routine and listening to your body’s natural cues can also support healthy bowel movements. If constipation develops after starting melatonin, consider lowering your dose or taking the supplement with a light snack to minimize digestive disruption. Should symptoms persist or worsen, consult a healthcare provider for further evaluation and personalized advice. For more information on constipation from supplements and management strategies, visit the Healthline guide to supplements and constipation.

39. Diarrhea

Diarrhea can occur as a side effect of melatonin supplementation, particularly in individuals with sensitive digestive systems or when higher doses are used. Melatonin may stimulate the gut’s enteric nervous system, leading to increased motility and faster transit of waste through the intestines. This overactive gut response can result in loose or frequent stools, abdominal cramping, and discomfort. The experience is similar to the effects seen with magnesium supplements, which are well-known for their laxative properties and tendency to cause diarrhea, especially when taken in excess.

If you develop diarrhea after starting melatonin, consider lowering your dose or taking the supplement with food to help buffer the digestive tract. Staying hydrated is critical, as diarrhea can quickly lead to fluid and electrolyte loss. If symptoms persist for more than a few days, become severe, or are accompanied by blood in the stool, dehydration, or significant abdominal pain, seek medical care promptly. Such signs could indicate an underlying gastrointestinal issue or a need for alternative sleep aids. For more information on managing diarrhea and supplement side effects, refer to the Healthline guide to diarrhea from supplements.

40. Decreased Appetite

Decreased appetite is a less common but possible side effect of melatonin supplementation. Melatonin may influence appetite-regulating hormones, such as leptin and ghrelin, leading to a reduced sensation of hunger. This appetite suppression can be similar to what some people experience during periods of acute stress, when hormonal shifts dampen the desire to eat. While a mild decrease in appetite may not pose significant health risks for most individuals, a prolonged loss of interest in food can impact nutritional status, particularly in those who are already underweight or have higher energy needs.

If you notice a marked reduction in appetite after beginning melatonin, keep track of your daily food and fluid intake to ensure you are meeting your nutritional requirements. Prioritize nutrient-dense meals and snacks, and set reminders for regular eating if your natural hunger cues are diminished. Should decreased appetite persist or lead to unintentional weight loss, consult a healthcare provider to explore alternative sleep aids or underlying causes. For more information on appetite loss and how supplements can contribute, visit the Healthline resource on appetite loss. Mindful monitoring helps maintain overall health while using melatonin.

41. Increased Appetite

While melatonin is more commonly associated with decreased appetite, there are rare cases where individuals report increased hunger after starting supplementation. This effect may stem from melatonin’s complex interaction with metabolic and appetite-regulating hormones, or it might be a rebound response as the body adjusts to changes in sleep quality. The sensation is similar to the rebound hunger often observed after periods of sleep deprivation, when the body produces more ghrelin—the hormone responsible for stimulating appetite—in an effort to restore energy balance. Improved sleep with melatonin might also prompt some people to feel hungrier as their circadian rhythms stabilize.

If you notice an uptick in hunger or cravings after beginning melatonin, focus on balanced eating habits and mindful portion sizes. Choose nutrient-dense foods such as whole grains, lean proteins, fruits, and vegetables to satisfy increased appetite without excess calorie intake. Keeping a food journal can help you track patterns and avoid mindless snacking, especially if nighttime hunger becomes a concern. Should increased appetite lead to significant weight gain or disrupt your nutritional goals, consult with a healthcare provider for advice. For more information on appetite changes and supplements, see the Healthline article on hunger and its causes.

42. Taste Changes

Altered taste perception, though rare, has been reported by some individuals using melatonin supplements. This side effect can manifest as a diminished sense of taste, a persistent unusual flavor, or even a metallic or bitter taste in the mouth. Such changes are reminiscent of the metallic taste often experienced by those taking certain antibiotics or other medications, which can interfere with taste receptor function or alter saliva composition. While the exact mechanism by which melatonin might cause taste changes is not fully understood, it may involve subtle shifts in the way the nervous system processes sensory information.

If you notice changes in your ability to taste food or detect unusual flavors after starting melatonin, keep track of when symptoms occur and any associated factors, such as dosage or timing. Maintaining good oral hygiene and staying hydrated can sometimes alleviate mild taste disturbances. If the altered taste persists, becomes bothersome, or interferes with your ability to enjoy food and maintain proper nutrition, consult a healthcare provider for further evaluation. For more information on taste changes related to medications and supplements, visit the Healthline article on metallic taste in the mouth. Early discussion with a provider can help identify solutions or alternative options.

43. Unsteady Gait

An unsteady gait, or difficulty maintaining balance while walking, is a potential side effect of melatonin, especially when taken in higher doses or close to bedtime. Melatonin’s sedative properties can slow neural processing and muscle coordination, making movement less precise and increasing the risk of stumbling or falls. This effect is similar to what some individuals experience after taking other sedative medications, such as benzodiazepines or certain prescription sleep aids, which can impair balance and motor skills. The risk is particularly significant in older adults, who may already have age-related challenges with stability.

To minimize the risk of falls, take melatonin when you are ready to go directly to bed and avoid activities that require alertness or coordination once the supplement has been ingested. Ensure that your bedroom and the route to the bathroom are free of tripping hazards, and consider using night lights for safe navigation in the dark. If you experience frequent episodes of unsteadiness or falls, consult a healthcare provider to review your dosage and explore safer sleep options. For more on medication-induced balance issues and fall prevention, visit the CDC’s fall prevention resource. Proactive strategies help protect your safety while using melatonin.

44. Difficulty Concentrating

Difficulty concentrating is a side effect occasionally reported by melatonin users, particularly when doses are too high or the supplement is taken too late at night. Melatonin’s sedative influence can extend into the following day, causing cognitive slowing or a sense of mental sluggishness. This “brain fog” is comparable to the lack of focus people often experience after a night of poor sleep, when the brain struggles to process information efficiently and sustain attention on complex tasks. For those whose work or daily activities demand high levels of concentration, even mild cognitive impairment can be frustrating and disruptive.

If you notice trouble concentrating after taking melatonin, try adjusting the dose or timing so that its effects fully wear off by the time you need to be alert. Starting with the lowest effective dose and taking melatonin 30-60 minutes before bedtime may help minimize next-day cognitive effects. If focus issues persist, consider alternative sleep strategies or consult a healthcare provider for personalized recommendations. For more information on melatonin’s cognitive side effects and how to manage them, see the Sleep Foundation’s guide to melatonin side effects. Adapting your routine can help maintain both restful sleep and mental clarity.

45. Restless Legs

Melatonin has been reported to aggravate symptoms of restless legs syndrome (RLS) in some individuals. RLS is characterized by unpleasant sensations in the legs and an uncontrollable urge to move them, typically worsening at night and during periods of rest. Although the exact mechanism is unclear, melatonin’s influence on dopamine pathways and the nervous system may contribute to increased leg discomfort or twitching. This aggravation is similar to the way iron deficiency can worsen RLS symptoms, as low iron levels also disrupt dopamine function and nerve signaling, intensifying the urge to move the legs.

If you experience new or worsening restless legs symptoms after starting melatonin, consider lowering your dose, adjusting the timing, or discontinuing the supplement to see if symptoms improve. Practicing good sleep hygiene, stretching before bed, and addressing potential underlying issues such as iron deficiency may also help reduce RLS discomfort. Persistent or severe symptoms should be discussed with a healthcare provider, who can recommend appropriate treatments and determine if melatonin is suitable for your needs. For more on restless legs syndrome and managing symptoms, visit the Sleep Foundation’s page on restless legs syndrome. Personalized management can help you achieve more restful, uninterrupted sleep.

46. Unusual Body Odor

Unusual body odor is a rare but possible side effect reported by some individuals taking melatonin. The hormone may induce subtle metabolic changes that affect the way the body processes certain compounds, potentially altering the composition of sweat and other bodily secretions. This phenomenon is somewhat similar to odor shifts experienced after dietary changes—such as consuming more garlic, onions, or certain supplements—which can lead to distinctive smells as metabolic byproducts are excreted through the skin. While not harmful, these changes can be surprising or concerning, especially if they are persistent or accompanied by other new symptoms.

If you notice a new or unusual body odor after starting melatonin, keep track of when it began and any other changes in your routine, including diet or hygiene products. Maintaining regular bathing and wearing breathable clothing can help minimize odor. Should the smell persist, worsen, or be associated with other symptoms such as fever or unexplained sweating, consult a healthcare provider to rule out underlying metabolic or medical conditions. For more information on how supplements and metabolism can affect body odor, see the Healthline article on body odor causes and treatments. Awareness and early attention can help ensure comfort and peace of mind.

47. Increased Sensitivity to Light

Increased sensitivity to light, or photophobia, is a rare side effect that some individuals may experience when taking melatonin. Melatonin is a key regulator of the body’s circadian rhythms and is naturally suppressed by exposure to light, particularly blue light. By artificially elevating melatonin levels, the body may become more acutely responsive to light cues, resulting in discomfort or squinting in bright environments. This response is somewhat similar to the photophobia experienced during migraines, where neurological changes heighten sensitivity to light, making even normal illumination feel irritating or overwhelming.

If you notice increased sensitivity to light after starting melatonin, consider managing your exposure by wearing sunglasses outdoors, using dimmable lights indoors, and reducing screen time, especially in the hours following supplementation. Installing blackout curtains or adjustable lighting in your bedroom can help maintain comfortable sleep and wake cycles. Should light sensitivity persist, interfere with daily activities, or be accompanied by vision changes or headaches, consult a healthcare provider for further evaluation. For more on circadian rhythms, melatonin, and photophobia, visit the Sleep Foundation’s guide to light and circadian rhythms. Proactive management helps maintain comfort and healthy sleep patterns.

48. Mood Swings

Mood swings are a potential side effect of melatonin supplementation, especially in individuals sensitive to hormonal changes. Melatonin interacts with neurotransmitters and hormones such as serotonin, dopamine, and cortisol, all of which play crucial roles in regulating mood and emotional stability. These hormonal fluctuations can lead to periods of irritability, sadness, or heightened emotional responses. The experience is similar to mood changes observed with other sleep aids or medications that influence brain chemistry, where users may notice sudden shifts in disposition or increased sensitivity to stress and daily challenges.

To better understand and manage mood variability while using melatonin, consider keeping a daily journal to track emotional patterns, triggers, and the timing of supplement intake. This can help identify correlations between melatonin use and mood changes, providing valuable information for you and your healthcare provider. If mood swings become frequent, severe, or disruptive to relationships and daily functioning, consult a medical professional for personalized advice or alternative sleep solutions. For additional guidance on the psychological effects of melatonin and managing mood swings, visit the Healthline article on melatonin side effects and mood. Early recognition and documentation can support effective management and emotional well-being.

49. Sleep Paralysis

Sleep paralysis is a phenomenon in which a person is temporarily unable to move or speak while falling asleep or waking up, often accompanied by vivid hallucinations or a sense of pressure. Melatonin’s impact on sleep architecture—particularly its enhancement of REM (rapid eye movement) sleep—may increase the likelihood of sleep paralysis in susceptible individuals. During REM sleep, the brain induces atonia, a natural paralysis of most voluntary muscles to prevent acting out dreams. When melatonin intensifies or prolongs REM periods, it can sometimes cause a mismatch in the timing of waking and muscle reactivation, leading to episodes of sleep paralysis.

These episodes are similar to typical sleep paralysis events but may occur more frequently or feel more intense after starting melatonin. To reduce the risk, focus on maintaining a regular sleep schedule, minimizing sleep deprivation, and managing stress, all of which are known triggers for sleep paralysis. If episodes become frequent or distressing, consider lowering your melatonin dose or consulting a sleep specialist. For further information on sleep paralysis, causes, and coping strategies, visit the Sleep Foundation’s page on sleep paralysis. Understanding and addressing contributing factors can help minimize these unsettling occurrences.

50. Dependency and Withdrawal

The question of whether melatonin can lead to dependency or withdrawal symptoms remains a topic of debate among sleep experts. Unlike many prescription sleep aids, melatonin is not classified as habit-forming, and most users do not develop a physiological dependence. However, some individuals report psychological reliance, feeling unable to fall asleep without the supplement. In rare cases, abruptly stopping melatonin after prolonged use may lead to rebound insomnia or difficulty initiating sleep, similar—though usually milder—to withdrawal symptoms experienced with other sleep medications such as benzodiazepines or Z-drugs.

If you are concerned about dependency or wish to discontinue melatonin after regular use, it is advisable to taper the dosage gradually rather than stopping suddenly. This approach allows your body’s natural sleep-wake cycle to readjust and minimizes the risk of rebound symptoms. Practicing good sleep hygiene, maintaining a consistent bedtime, and exploring non-pharmacological sleep strategies can support the transition. If withdrawal symptoms persist or significantly disrupt sleep, consult a healthcare provider for personalized guidance. For more information on dependency, withdrawal, and safe discontinuation, refer to the Sleep Foundation’s guide on stopping melatonin. Thoughtful management ensures lasting, healthy sleep habits.

Conclusion

As melatonin’s popularity grows worldwide, it is essential to recognize its full profile of potential side effects alongside its well-known sleep benefits. While generally safe for many, melatonin can cause a range of mild to rare but significant reactions. Consulting a healthcare professional before starting or stopping supplementation ensures appropriate guidance, especially for those with underlying conditions or taking other medications. Keeping a journal of symptoms and sleep patterns can help identify issues early, while prompt medical screening is recommended if new or troubling symptoms develop. For further guidance, refer to resources such as the Sleep Foundation’s melatonin side effects guide.

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