Signs of an Underactive Thyroid in Adults

1. Persistent Fatigue

One of the most common and noticeable symptoms of an underactive thyroid is persistent fatigue. Unlike the typical tiredness experienced after a long day or lack of sleep, fatigue caused by hypothyroidism is ongoing and does not improve with rest. This occurs because low levels of thyroid hormone slow down the body’s metabolic processes, reducing energy production in nearly every cell. As a result, individuals may feel exhausted even after a full night’s sleep or without engaging in strenuous activities.

This type of fatigue can interfere with daily tasks, making it difficult to concentrate, stay motivated, or maintain regular routines. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), feeling unusually tired or weak is a hallmark sign of hypothyroidism. If fatigue is persistent, unexplained, and accompanied by other symptoms such as weight gain or sensitivity to cold, it may be a warning signal that the thyroid is underactive. Consulting a healthcare provider for evaluation and blood testing is recommended if fatigue disrupts daily life or does not improve with typical lifestyle adjustments.

2. Unexplained Weight Gain

Unexplained weight gain is another key sign of an underactive thyroid. When thyroid hormone levels are low, the body’s metabolic rate decreases, leading to fewer calories being burned throughout the day. This means that even if a person’s eating habits and physical activity remain the same, they may still notice a gradual increase in weight. The weight gained due to hypothyroidism is often subtle at first but can become more noticeable over time, particularly as water and salt are retained by the body.

For example, someone who has maintained a stable weight for years might suddenly gain 5 to 10 pounds within a few months, despite sticking to their usual diet and exercise routine. According to the Endocrine Society, this type of weight gain is generally modest but persistent and is often one of the earliest clues to thyroid dysfunction. If you notice unexplained weight gain that isn’t related to changes in food intake or activity level, especially if it’s accompanied by symptoms like fatigue or dry skin, it’s important to consult a healthcare provider. Early evaluation can help identify hypothyroidism and prevent further complications.

3. Increased Sensitivity to Cold

Increased sensitivity to cold is a classic symptom of an underactive thyroid and is closely linked to the gland’s role in regulating metabolism and body temperature. Thyroid hormones stimulate energy production in the body’s cells, generating heat as a byproduct. When hormone levels drop, the body’s ability to produce and conserve heat diminishes, leaving individuals feeling unusually chilly even in environments that are comfortable for others.

Unlike the normal sensation of being cold in a chilly room or during winter weather, people with hypothyroidism may feel cold in mild conditions or when others do not. They might find themselves reaching for extra layers, blankets, or hot drinks more frequently than before. According to the Mayo Clinic, this heightened cold intolerance is often persistent and can be accompanied by other symptoms such as fatigue or dry skin.

If you consistently feel colder than those around you or notice a change in your tolerance to cool temperatures, it could be a sign of thyroid dysfunction. It is advisable to seek medical evaluation, especially if this symptom is new or occurs with other signs of hypothyroidism.

4. Dry Skin

Thyroid hormones play a vital role in maintaining skin health and hydration. When the thyroid is underactive, the body’s metabolic processes slow down, which impacts the normal turnover of skin cells and decreases the production of natural oils. This leads to skin that feels rough, flaky, or scaly, and may appear pale or dull. Unlike seasonal dryness or mild dehydration, hypothyroidism-related dry skin is often persistent and may not respond well to regular moisturizers.

For instance, an individual might notice that their skin remains dry and itchy even after applying lotion regularly or increasing their water intake. According to the American Academy of Dermatology Association (AAD), this dryness can sometimes be severe enough to cause cracking or even eczema-like patches. In addition, other symptoms such as hair thinning or brittle nails may accompany skin changes, further pointing to a systemic hormonal imbalance.

While dry skin is a common cosmetic concern, persistent or worsening dryness—especially when it doesn’t improve with typical skincare routines—may indicate an underlying health issue like hypothyroidism. If these symptoms are present, it is important to consult a healthcare provider for further evaluation.

5. Hair Loss or Thinning

Thyroid hormones are essential for the growth and maintenance of healthy hair. They help regulate the hair growth cycle, ensuring that follicles move smoothly through their phases of growth, rest, and shedding. When thyroid hormone levels are low, the growth cycle becomes disrupted, causing more hair follicles to enter the resting phase prematurely. This leads to increased hair shedding and noticeable thinning, not just on the scalp but sometimes on the eyebrows and other body hair as well.

For example, someone might observe an unusual amount of hair left on their pillow in the morning, a clogged shower drain after washing, or a widening part on their scalp. According to the British Thyroid Foundation, hair loss due to hypothyroidism typically develops gradually and can be overlooked until it becomes more pronounced.

If you notice significant hair thinning, diffuse hair loss, or changes in the texture of your hair—such as it becoming dry and brittle—these could be warning signs of an underactive thyroid. Especially if hair changes are accompanied by other symptoms like fatigue or dry skin, seeking medical advice is recommended for proper assessment.

6. Constipation

Constipation is a frequent yet often overlooked symptom of an underactive thyroid. Thyroid hormones play a significant role in regulating the speed at which food moves through the digestive tract. When hormone levels are insufficient, the muscles in the intestines contract less frequently, leading to slowed digestion and infrequent, hard, or difficult-to-pass stools. This is in contrast to occasional constipation due to dietary changes, dehydration, or travel, which typically resolves with increased fiber intake or hydration.

Individuals with hypothyroidism may find themselves having fewer bowel movements than usual—sometimes only a few times per week—and may also experience bloating or abdominal discomfort. According to the National Institutes of Health (NIH), persistent constipation is a common gastrointestinal complaint among those with thyroid dysfunction.

While occasional constipation is normal, ongoing difficulty with bowel movements that does not improve with typical remedies—such as dietary adjustments or over-the-counter treatments—may indicate a deeper underlying issue like hypothyroidism. If constipation becomes chronic or is accompanied by other symptoms such as fatigue or unexplained weight gain, it’s important to consult a healthcare provider for further evaluation and appropriate management.

7. Muscle Weakness

Muscle weakness is a less obvious but important symptom of an underactive thyroid. Thyroid hormones are crucial for muscle metabolism, helping cells convert nutrients into energy efficiently. When hormone levels are low, muscles do not receive enough stimulation or fuel, leading to reduced strength and endurance. This weakness typically affects the larger muscles in the body, such as those in the thighs, hips, shoulders, and arms.

Real-life examples include struggling to climb stairs, difficulty rising from a seated position, or feeling unusually fatigued after activities that were once easy, like carrying groceries or walking short distances. According to the Hormone Health Network, muscle cramps, stiffness, and aches may also accompany the weakness, further impacting daily function.

While temporary muscle fatigue can result from overexertion or inactivity, persistent muscle weakness—especially if it worsens over time or interferes with routine activities—should not be ignored. If you notice ongoing reduction in muscle strength without a clear cause, and particularly if it is accompanied by other signs such as fatigue or joint pain, it is wise to seek a medical evaluation to rule out hypothyroidism or other underlying conditions.

8. Joint Pain or Stiffness

Joint pain or stiffness can be a subtle but significant sign of hypothyroidism. When thyroid hormone levels are low, inflammation can develop in the connective tissues, leading to discomfort, swelling, or reduced flexibility in the joints. This process may also slow the repair of tissues, making recovery from minor strains or injuries more prolonged. While joint pain is often associated with conditions like arthritis, the pain from hypothyroidism tends to be milder and more widespread, often affecting multiple joints and accompanied by muscle aches or cramps.

Unlike arthritis, which typically causes redness, warmth, or pronounced swelling in specific joints, hypothyroid-related joint pain is usually less severe but more persistent. Individuals may notice stiffness after periods of inactivity, such as waking up in the morning or sitting for extended periods. According to the Versus Arthritis organization, such symptoms may improve with thyroid hormone replacement therapy but can impact mobility and quality of life if left untreated.

If you experience ongoing joint discomfort or stiffness that is not explained by injury or another medical condition, especially when paired with other hypothyroid symptoms, it is important to mention these concerns to your healthcare provider for further assessment.

9. Heavier or Irregular Periods

The thyroid gland plays a vital role in regulating many body systems, including the reproductive system. Low thyroid hormone levels can disrupt the balance of reproductive hormones, leading to changes in menstrual cycles. Women with hypothyroidism may experience periods that are heavier, longer, or more frequent than usual, or cycles that become unpredictable and irregular. This disruption occurs because thyroid hormones interact with the hormones that control the menstrual cycle, such as estrogen and progesterone.

For example, a woman who typically has a regular, moderate menstrual flow might suddenly find her periods lasting much longer, with significantly heavier bleeding and increased cramping. According to the U.S. Department of Health & Human Services: Office on Women’s Health, menstrual changes can be one of the first signs of thyroid dysfunction in women of reproductive age.

If you notice a marked change in your menstrual cycle—such as heavier bleeding, missed periods, or unpredictability—especially if it is accompanied by other symptoms like fatigue or weight gain, it is important to consult a healthcare provider. Early diagnosis and management of hypothyroidism can help restore normal menstrual patterns and prevent further complications.

10. Slowed Heart Rate

A slowed heart rate, known medically as bradycardia, is another potential symptom of an underactive thyroid. Thyroid hormones help regulate the heart’s electrical system and ensure that the heart beats at an appropriate speed and rhythm. When thyroid hormone levels are low, the heart’s activity slows down, leading to a reduced pulse rate. Typically, a healthy adult heart beats between 60 and 100 times per minute, but hypothyroidism can cause this rate to drop below the normal range.

Unlike other heart rate issues such as palpitations or rapid heartbeat, a slow heart rate due to hypothyroidism usually develops gradually and may be accompanied by symptoms like fatigue, dizziness, or even shortness of breath. For example, a person who previously had a normal pulse might notice their heart beating more slowly and feel unusually tired or lightheaded during routine activities. According to the American Heart Association, bradycardia associated with hypothyroidism can sometimes lead to more serious cardiovascular complications if left untreated.

If you notice a persistently slow pulse, especially if it is accompanied by weakness, fainting, or other symptoms of hypothyroidism, it is important to seek medical evaluation. Timely diagnosis can help prevent further heart-related issues.

11. Depression or Low Mood

Thyroid hormones play a key role in regulating brain chemistry and emotional wellbeing. When levels are low, neurotransmitters such as serotonin and dopamine, which influence mood, can become imbalanced. As a result, individuals with hypothyroidism often experience symptoms of depression, low mood, or a general sense of emotional dullness. These feelings may arise even in the absence of other obvious causes, making it harder to recognize the underlying thyroid issue.

For instance, someone who is usually optimistic and energetic may begin to withdraw socially, lose interest in hobbies, or feel persistently sad without explanation. Even day-to-day tasks can begin to feel overwhelming or pointless. According to the National Institutes of Health (NIH), depressive symptoms are common in untreated hypothyroidism and can significantly impact quality of life.

If you notice a persistent change in mood, motivation, or mental clarity—especially if these changes are new or uncharacteristic—it may be worth considering thyroid dysfunction as a possible cause. Consulting a healthcare provider is important, particularly if mood changes are accompanied by physical symptoms such as fatigue, weight gain, or constipation.

12. Impaired Memory or Concentration

Many adults with an underactive thyroid experience so-called “brain fog,” characterized by impaired memory, difficulty concentrating, and slowed thinking. Thyroid hormones are crucial for optimal brain function, supporting neurotransmitter activity and maintaining the health of brain cells. When these hormone levels are low, cognitive processes can slow down, making it harder to focus, recall information, or complete complex tasks.

For example, a person may find themselves forgetting appointments, struggling to follow conversations, or taking significantly longer to solve problems at work or home. These mental lapses can be frustrating and may be mistaken for normal aging or stress. According to the EndocrineWeb, cognitive impairment is a recognized symptom of hypothyroidism and often improves with adequate thyroid hormone replacement therapy.

If you notice persistent issues with memory or concentration that are unusual for you, especially when accompanied by other symptoms like fatigue or depression, it’s important to seek medical advice. Early identification and management of hypothyroidism can help reverse cognitive symptoms and improve overall mental sharpness.

13. Puffy Face

A puffy or swollen face is a classic but sometimes overlooked symptom of an underactive thyroid. Hypothyroidism can cause the body to retain excess fluid and salt, leading to swelling in various areas—including the face. Unlike the mild puffiness that some people experience in the morning due to sleep position or minor dehydration, hypothyroidism-related facial puffiness is often persistent and more noticeable, especially around the eyes, cheeks, and lips.

For example, someone may observe that their face looks fuller in photos, their eyelids appear swollen, or they develop noticeable bags under the eyes that don’t resolve with usual remedies. According to the Mayo Clinic, this type of facial swelling—sometimes referred to as myxedema—can be a key indicator of severe or prolonged hypothyroidism.

If you notice that facial puffiness doesn’t subside throughout the day or becomes more pronounced over time, it’s important to pay attention, especially if it’s accompanied by other symptoms such as fatigue, dry skin, or weight gain. Persistent or worsening puffiness should prompt a discussion with a healthcare provider to rule out thyroid dysfunction or other underlying conditions.

14. Hoarseness

Hoarseness is another potential sign of an underactive thyroid, often overlooked due to its gradual onset. The thyroid gland is located at the base of the neck, close to the larynx (voice box) and vocal cords. When hypothyroidism develops, the gland can become enlarged or inflamed—a condition known as a goiter—which may press on the vocal cords and change the quality of the voice. Additionally, low thyroid hormone levels can contribute to fluid retention and swelling in the tissues around the throat, further affecting vocal function.

For example, a person might notice their voice becoming deeper, raspier, or weaker over weeks or months, even though they haven’t had a cold, allergies, or overused their voice. According to the Mount Sinai Health Library, persistent hoarseness without an obvious cause is a symptom that warrants investigation, especially in the context of other signs of hypothyroidism.

If you experience voice changes that last for more than a couple of weeks—particularly if accompanied by swallowing difficulties, neck swelling, or other thyroid-related symptoms—it’s important to consult a healthcare professional. Early evaluation can help identify underlying thyroid issues before they progress.

15. Elevated Blood Cholesterol

Hypothyroidism can significantly impact cholesterol metabolism, often resulting in elevated levels of total cholesterol and low-density lipoprotein (LDL) cholesterol. Thyroid hormones help regulate how the body processes and removes excess cholesterol from the bloodstream. When hormone levels are low, this process slows down and cholesterol accumulates, increasing the risk of heart disease over time.

For instance, someone who previously had normal cholesterol readings might be surprised to find that their cholesterol levels have risen sharply at their annual checkup, despite no changes in diet, exercise, or weight. According to the Centers for Disease Control and Prevention (CDC), unexplained high cholesterol is a common finding in people with undiagnosed hypothyroidism and may be the first clue that something is amiss.

If routine blood tests reveal elevated cholesterol that does not respond to lifestyle modifications, it is advisable to discuss thyroid testing with your healthcare provider. Monitoring cholesterol levels regularly is important, especially if you have other risk factors for heart disease or symptoms of hypothyroidism. Proper management of thyroid function can help restore healthy cholesterol levels and reduce cardiovascular risk.

16. Swelling in the Neck (Goiter)

Swelling in the front of the neck, known as a goiter, is a physical sign that can indicate an underactive thyroid. When the thyroid gland struggles to produce enough hormones, it can become enlarged as it works harder to compensate for the hormone deficit. This enlargement may be diffuse, affecting the entire gland, or nodular, causing lumps or bumps within the thyroid. Unlike other neck lumps—which might be due to lymph nodes, cysts, or infections—a goiter is typically located at the base of the neck and moves up and down when swallowing.

For example, a person might notice a visible swelling at the front of the neck when looking in the mirror or feel a fullness or tightness when buttoning a shirt collar. According to the NHS, goiters can vary in size from barely noticeable to quite prominent and may or may not be accompanied by discomfort or difficulty swallowing.

If you detect new swelling, a lump, or a feeling of fullness in your neck—especially if accompanied by symptoms such as hoarseness, difficulty swallowing, or other signs of hypothyroidism—it is important to have it evaluated by a healthcare provider. Early assessment can help determine the cause and appropriate treatment.

17. Brittle Nails

Brittle nails are a lesser-known but telling indicator of an underactive thyroid. Thyroid hormones are essential for the maintenance and healthy growth of nails, as they regulate the rate at which nail cells are produced and replaced. When thyroid function declines, nail growth slows, leading to nails that are thin, dry, and more prone to splitting, cracking, or developing ridges. Reduced blood flow and nutrient delivery to the nail beds further compromise nail strength and resilience.

For instance, someone might notice their nails breaking more easily while performing routine tasks, or observe that their nails seem to peel or chip even without trauma. According to the Harvard Health Publishing, these changes can be subtle at first but often become more pronounced if hypothyroidism is left untreated.

It’s important to monitor nail health, especially if changes occur along with other symptoms like dry skin, hair thinning, or fatigue. Persistent brittleness, slow nail growth, or the sudden appearance of ridges should prompt a conversation with your healthcare provider. Nail changes can serve as an early clue to underlying thyroid dysfunction and should not be overlooked.

18. Reduced Sweating

Reduced sweating is a subtle but significant symptom of an underactive thyroid. Thyroid hormones help regulate the body’s metabolism and, consequently, the production of sweat. When hormone levels drop, metabolic activity slows, leading to decreased heat generation and a corresponding reduction in sweat. This is in stark contrast to normal sweating, which typically occurs in response to physical exertion, heat, or emotional stress as the body works to cool itself.

For example, someone with hypothyroidism may find that they rarely sweat during exercise or hot weather, while others around them perspire normally. According to the MSD Manuals, this noticeable lack of sweating—sometimes referred to as “dry skin with reduced perspiration”—can be particularly striking if it represents a change from a person’s usual level of sweat production.

If you observe a persistent reduction in your ability to sweat, especially when combined with other symptoms like cold intolerance, dry skin, or fatigue, it may be time to consult a healthcare provider. Reduced sweating is often overlooked but can be an important early sign of hypothyroidism that warrants further investigation.

19. Carpal Tunnel Syndrome

Carpal tunnel syndrome is a condition often associated with repetitive hand movements but can also be linked to hypothyroidism. Low thyroid hormone levels can cause the tissues in the body, including those in the wrists, to swell and retain fluid. This swelling can compress the median nerve as it passes through the carpal tunnel in the wrist, leading to symptoms such as numbness, tingling, weakness, or pain in the hands and fingers.

For example, an individual may notice their hands frequently falling asleep at night or find it increasingly difficult to grip objects, button shirts, or perform fine motor tasks. According to the American Thyroid Association, carpal tunnel syndrome is a known complication of untreated or prolonged hypothyroidism and may affect one or both hands.

If you experience persistent symptoms of carpal tunnel syndrome—especially if you do not have a history of repetitive hand use, injury, or other risk factors—it is important to consider thyroid dysfunction as a possible cause. Early evaluation and treatment of hypothyroidism can help relieve nerve compression and prevent lasting nerve damage.

20. Loss of Libido

Loss of libido, or reduced interest in sexual activity, is a common but frequently unspoken symptom of hypothyroidism. Thyroid hormones play a crucial role in regulating reproductive hormones and maintaining overall energy and mood. When thyroid function is diminished, there is often a decrease in the production of sex hormones such as estrogen and testosterone, leading to a lowered sex drive. Additionally, other symptoms of hypothyroidism—such as fatigue, depression, and weight gain—can further reduce interest in intimacy.

For instance, a person who previously enjoyed an active sex life may find themselves uninterested in or avoiding sexual activity, even in the absence of relationship issues or emotional stress. According to the Harvard Health Publishing, sexual dysfunction, including loss of libido, is often improved once thyroid hormone levels are restored to normal with treatment.

If you notice a persistent or unexplained drop in sexual desire, especially if it is accompanied by other symptoms like fatigue, mood changes, or menstrual irregularities, it’s important to discuss these changes with a healthcare professional. Addressing thyroid health can often help restore sexual wellbeing and improve overall quality of life.

21. Infertility

Hypothyroidism can significantly affect fertility by disrupting the balance of reproductive hormones needed for ovulation and conception. Low thyroid hormone levels interfere with the release of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH), all of which are critical for regular menstrual cycles and the release of eggs from the ovaries. In men, hypothyroidism can reduce sperm count and motility, also impacting fertility.

For example, a couple may try to conceive for several months or even years without success, despite regular cycles and no apparent reproductive issues. The underlying cause might only become apparent after thyroid testing, which reveals an underactive thyroid as the root of the problem. According to the American Society for Reproductive Medicine, thyroid hormone imbalances are a common and treatable cause of infertility in both women and men.

If you are experiencing difficulty conceiving, especially when accompanied by other symptoms such as irregular periods, fatigue, or unexplained weight changes, it is important to discuss thyroid testing with your healthcare provider. Early diagnosis and treatment of hypothyroidism can often restore fertility and improve reproductive outcomes.

22. Hearing Loss

Although less common than other symptoms, hearing loss can be associated with hypothyroidism. Low thyroid hormone levels may affect the nerves and blood vessels that supply the inner ear, potentially leading to conductive, sensorineural, or mixed hearing loss. The mechanisms are not fully understood, but researchers believe that fluid retention, slowed metabolism, and nerve dysfunction play a role.

For example, an adult with hypothyroidism might notice a gradual decline in their ability to hear conversations, needing to turn up the television volume, or experiencing muffled sounds even in quiet environments. According to a review in the Indian Journal of Endocrinology and Metabolism, hearing impairment is more likely in cases of long-standing or untreated hypothyroidism, but it can sometimes improve with proper thyroid hormone replacement therapy.

If you experience new or worsening hearing difficulties—especially if accompanied by other signs of hypothyroidism such as fatigue, dry skin, or weight gain—it is important to mention this to your healthcare provider. Prompt evaluation can help determine whether thyroid dysfunction is a contributing factor and guide appropriate management to prevent further hearing decline.

23. Slow Speech

Slow speech is a subtle yet telling manifestation of hypothyroidism, resulting from the hormone’s impact on neuromuscular function. Thyroid hormones help maintain the speed and coordination of nerve impulses and muscle actions, including those involved in speaking. When thyroid levels are low, the processes that control movement and coordination of the tongue, lips, and vocal cords can become sluggish. This can cause a person’s speech to sound unusually slow, deliberate, or even slightly slurred.

For example, a normally articulate individual may notice it takes more effort to find words or form sentences, speaking more slowly than usual and needing to pause frequently. Friends or coworkers might comment on the change, or misunderstandings may occur more often because of hesitant or unclear speech. According to the National Center for Biotechnology Information (NCBI), slow speech is sometimes observed in severe or prolonged hypothyroidism and can be accompanied by cognitive changes and facial puffiness.

If you or those around you notice persistent changes in the pace or clarity of your speech—especially alongside symptoms like fatigue, memory issues, or facial swelling—it’s important to mention this to your healthcare provider. Slow speech can be an early neurological clue to hypothyroidism requiring further evaluation.

24. Enlarged Tongue

An enlarged tongue, or macroglossia, is a less common but distinctive sign of hypothyroidism. Low thyroid hormone levels can cause generalized tissue swelling, known as myxedema, which may also affect the tongue. This results in a tongue that appears larger, feels thickened, or develops scalloped edges from pressing against the teeth. Unlike swelling from allergic reactions, infections, or trauma—which tends to be sudden and associated with pain or redness—hypothyroid-related tongue enlargement is usually gradual and painless.

For instance, a person might notice changes in their speech, increased snoring, or trouble fitting their tongue comfortably in the mouth. Dental impressions along the sides of the tongue or difficulty swallowing are also possible. According to the Journal of Oral and Maxillofacial Pathology, macroglossia can be an important physical clue to longstanding or untreated hypothyroidism.

If you observe persistent tongue enlargement, scalloping, or new difficulties with speech or swallowing, it is important to mention these changes to your healthcare provider. When seen with other symptoms like puffy face, slow speech, or fatigue, an enlarged tongue may help point toward a thyroid problem that requires further assessment.

25. Shortness of Breath

Shortness of breath can occur in individuals with hypothyroidism due to the hormone’s influence on lung function and the body’s ability to utilize oxygen efficiently. Thyroid hormones play a crucial role in maintaining respiratory muscle strength, lung tissue health, and the rate at which the body consumes oxygen. When thyroid levels are low, breathing muscles may weaken, and the tissues’ ability to extract and use oxygen decreases, leading to a sensation of breathlessness, especially during physical activity.

For example, a person who previously climbed stairs or walked briskly without any issues might begin to notice they become winded more quickly, even with mild exertion. According to the National Institutes of Health (NIH), some people with hypothyroidism may also experience shallow or slow breathing, and, in severe cases, fluid retention related to myxedema can further impact lung capacity.

If you experience new or worsening shortness of breath, particularly if it is persistent, occurs at rest, or is associated with other symptoms like fatigue, puffy face, or muscle weakness, it is important to seek medical attention. Early recognition and treatment of hypothyroidism can help improve respiratory symptoms and overall well-being.

26. High Blood Pressure

High blood pressure, or hypertension, can be an unexpected consequence of hypothyroidism. Thyroid hormones help regulate the flexibility of blood vessels and maintain optimal heart function. When these hormone levels fall, blood vessels become less elastic, causing increased resistance to blood flow and, consequently, elevated blood pressure. This effect can be more pronounced in the diastolic (bottom) number of a blood pressure reading.

Unlike traditional risk factors for high blood pressure such as obesity, high salt intake, or lack of physical activity, hypothyroidism-induced hypertension may develop even in otherwise healthy individuals. For example, a person with no prior history or family risk of hypertension might be surprised by consistently high readings during routine checkups. According to the National Institutes of Health (NIH), treating underlying thyroid dysfunction can help normalize blood pressure in many cases.

If you notice elevated blood pressure readings—especially if accompanied by symptoms such as fatigue, weight gain, or cold intolerance—it’s advisable to discuss thyroid testing with your healthcare provider. Regular monitoring and management of both thyroid health and blood pressure are critical to reducing the risk of cardiovascular complications.

27. Difficulty Losing Weight

Difficulty losing weight despite diligent efforts is a frustrating yet common experience for adults with hypothyroidism. Thyroid hormones play a central role in regulating metabolism, determining how efficiently the body burns calories. When these hormone levels are low, metabolic processes slow down, making it harder to lose weight even with calorie restriction and regular exercise.

For instance, someone who consistently follows a healthy diet and maintains an active lifestyle may find that the scale barely budges or progress stalls altogether. This can be discouraging and often leads to self-blame or repeated, unsuccessful attempts at weight loss. According to the Endocrine Society, hypothyroidism is a recognized cause of resistance to weight loss, and metabolic slowdown can persist until thyroid hormone levels are brought back to normal.

If you are struggling to lose weight despite making sustained, healthy changes to your diet and activity, and especially if you notice other symptoms like fatigue, dry skin, or cold intolerance, it may be time to discuss thyroid evaluation with your healthcare provider. Addressing underlying thyroid dysfunction can help restore a more normal metabolic rate and improve weight management outcomes.

28. Pale or Yellowish Skin

Pale or yellowish skin can be a visible sign of an underactive thyroid. When thyroid hormone levels are low, the body’s metabolism slows, which can reduce blood flow and oxygen delivery to the skin, causing it to appear unusually pale. Additionally, hypothyroidism can affect the breakdown of beta-carotene—a pigment found in carrots and other vegetables—leading to a subtle yellowish tint, especially on the palms and soles. This yellowing occurs without changes in the whites of the eyes, distinguishing it from jaundice caused by liver problems.

For example, someone might notice their complexion seems duller or more washed out than usual, or friends and family comment that they look “tired” or “unwell.” According to the American Academy of Dermatology Association, these skin changes often develop gradually and may be accompanied by other symptoms such as dryness or hair thinning.

If you observe persistent changes in your skin color—especially pallor or yellowish tones not explained by diet or sun exposure—it is important to discuss these findings with a healthcare provider. Skin changes, when combined with other symptoms, can be an early clue to thyroid dysfunction and warrant further investigation.

29. Slow Healing of Wounds

Slow healing of wounds is another symptom that can arise from an underactive thyroid. Thyroid hormones are essential for cellular repair and regeneration throughout the body, including the skin and other tissues. When hormone levels are low, cell turnover slows and the body’s inflammatory response becomes less effective, leading to delayed recovery from cuts, scrapes, bruises, or surgical incisions.

For example, a person might notice that a minor kitchen cut or shaving nick takes much longer than normal to close up, or that bruises linger for weeks rather than days. According to the Cleveland Clinic, impaired wound healing is particularly concerning when coupled with other signs of hypothyroidism, such as dry skin, hair loss, or persistent fatigue.

If you observe that small wounds, sores, or bruises are unusually slow to heal—or if they become infected more easily than in the past—it’s important to mention this to your healthcare provider. Delayed healing should not be ignored, as it may indicate underlying thyroid dysfunction or another health problem that requires prompt attention and management.

30. Decreased Appetite

Decreased appetite is a lesser-known but possible sign of hypothyroidism. When thyroid hormone levels drop, the body’s overall metabolic rate slows, which can dull hunger signals and result in reduced interest in food. This contrasts with other conditions such as depression, gastrointestinal disorders, or infections, where loss of appetite is often accompanied by rapid weight loss or gastrointestinal symptoms. In hypothyroidism, a decreased appetite may paradoxically coexist with weight gain or difficulty losing weight, due to the markedly slower metabolism.

For example, someone may find that they skip meals more often or feel full after eating much less than usual, yet continue to gain weight or experience bloating. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), appetite changes—especially when combined with fatigue, constipation, and cold intolerance—can be important clues to underlying thyroid dysfunction.

If you notice a persistent reduction in your appetite that is not explained by stress, illness, or dietary changes, it’s wise to track this symptom and discuss it with your healthcare provider. Monitoring changes in appetite, especially alongside other subtle symptoms, can help in the early detection of hypothyroidism.

31. Swelling in Hands and Feet

Swelling in the hands and feet, known as peripheral edema, is another sign that can be linked to hypothyroidism. Low thyroid hormone levels can cause the body to retain salt and water, leading to the buildup of fluid in the tissues, particularly in the extremities. This swelling is often described as “puffy” and may feel doughy or leave an indentation when pressed—a phenomenon known as “pitting edema.” It typically develops gradually and may worsen over the course of the day.

For example, an individual might notice their rings or shoes feel tighter than usual, or they may observe visible swelling around the ankles, wrists, or fingers. According to the MSD Manuals, this type of swelling is more likely to be persistent and less responsive to elevation or movement, especially compared to swelling from injury or temporary inactivity.

If you experience persistent or unexplained swelling in your hands or feet—particularly if it is accompanied by other symptoms such as fatigue, dry skin, or weight gain—it is important to consult with a healthcare provider. Early evaluation can help identify underlying thyroid dysfunction and prevent further complications.

32. Reduced Reflexes

Reduced reflexes, particularly the slowing of the relaxation phase after a tendon is tapped, are a classic neurological sign of hypothyroidism. Thyroid hormones are essential for normal nerve conduction and muscle function. When hormone levels are low, signals between nerves and muscles transmit more slowly, resulting in delayed or diminished reflex responses. This slowing is most commonly observed in the ankle (Achilles) reflex but can affect other reflexes as well.

In healthy individuals, tapping a tendon with a reflex hammer produces a quick, brisk muscle contraction and relaxation. In contrast, someone with hypothyroidism may notice that their reflexes seem “sluggish” or take longer to return to normal position. According to the National Center for Biotechnology Information (NCBI), this neurological finding is often subtle and may not be noticed without a clinical examination, but it can be an important clue in diagnosing thyroid dysfunction.

If you or your healthcare provider notice changes in your reflexes—such as slower movement or weaker responses during a physical exam—it is important to monitor these signs, especially if you experience other symptoms of hypothyroidism. Discussing these changes with a provider can help ensure timely diagnosis and treatment.

33. Thinning Eyebrows (Outer Third)

Thinning of the outer third of the eyebrows is a classic and distinctive sign of hypothyroidism, sometimes referred to as “Queen Anne’s sign.” Thyroid hormones are vital for healthy hair growth, including the fine hairs that make up the eyebrows. When hormone levels are low, the normal hair growth cycle is disrupted, leading to gradual loss of hair on the outer edges of the brows while the inner portion remains relatively intact. This pattern is less commonly seen in other conditions or as a result of normal aging.

For example, someone might notice that their eyebrows appear sparser at the temples or that penciling in the outer sections becomes a daily necessity. According to the American Academy of Dermatology Association, this eyebrow thinning often develops slowly and may be one of the first visible signs of an underactive thyroid, sometimes preceding other symptoms such as hair loss or dry skin.

If you observe persistent thinning or loss of the outer third of your eyebrows—especially when accompanied by other symptoms like fatigue, cold intolerance, or weight gain—it is important to mention this to your healthcare provider. Eyebrow changes can be an early and telling clue that warrants thyroid evaluation.

34. Low Body Temperature

Low body temperature is a notable sign of hypothyroidism, reflecting the role of thyroid hormones in regulating metabolic rate and heat production. The thyroid gland controls how much energy your body uses and, consequently, how much heat it generates. When thyroid hormone levels are insufficient, the body’s metabolism slows, leading to a drop in core temperature. This can cause individuals to consistently register body temperatures below the typical 98.6°F (37°C), often in the 97-98°F (36.1-36.6°C) range or even lower.

For example, a person may notice that they frequently feel cold, even in warm environments, and that their thermometer readings are lower than expected during routine checks. This trend may persist over days or weeks. According to the American Thyroid Association, low body temperature is often linked to other symptoms of slowed metabolism, such as fatigue and weight gain.

If you regularly find your body temperature is lower than normal—especially if you also experience other symptoms like fatigue, cold intolerance, or slow heart rate—it’s helpful to track these readings over time. Persistent low body temperature should be discussed with a healthcare provider, as it may indicate underlying thyroid dysfunction.

35. Slow Growth of Hair and Nails

Slow growth of hair and nails is a subtle but important indicator of hypothyroidism. Thyroid hormones stimulate cell turnover and regeneration, processes essential for the normal growth of hair and nails. When hormone levels drop, these cycles slow down, resulting in hair and nails that grow noticeably more slowly than usual. This can affect the length, thickness, and overall health of both hair and nails, leading to additional problems such as brittleness or thinning.

For example, someone who normally needs to trim their nails or get a haircut every few weeks may begin to notice that these tasks are required less often, or that their nails and hair appear more fragile and less vibrant. According to the American Academy of Dermatology Association, slow hair and nail growth often occurs alongside other symptoms such as dry skin, hair thinning, or changes in nail texture.

If you observe a marked reduction in the rate at which your hair or nails grow—especially when combined with other changes like brittleness, thinning, or loss—it’s a good idea to monitor these patterns and discuss them with your healthcare provider. Slowed growth can be a key clue to underlying thyroid dysfunction.

36. Trouble Sleeping

Trouble sleeping is a less obvious but impactful symptom of hypothyroidism. Thyroid hormones influence many bodily systems, including those that regulate sleep-wake cycles, body temperature, and mood. When thyroid hormone levels are low, individuals may experience difficulty falling asleep, frequent nighttime awakenings, or unrefreshing sleep. This is often due to symptoms such as muscle aches, joint pain, or a general sense of discomfort, as well as the effects of slowed metabolism on the body’s natural rhythms.

For example, a person who previously slept soundly may begin waking up several times a night feeling cold or restless, or may feel groggy and unrefreshed despite spending adequate hours in bed. According to the Sleep Foundation, untreated hypothyroidism can lead to sleep disturbances due to both physical symptoms and changes in brain chemistry that affect sleep patterns.

If you notice a persistent change in your sleep quality—especially if it’s accompanied by other signs like fatigue, weight gain, or muscle aches—it’s important to mention it to your healthcare provider. Chronic sleep problems can be an early clue to thyroid dysfunction and should prompt further evaluation.

37. Loss of Outer Eyelashes

Loss of the outer eyelashes is a distinctive sign that can point to hypothyroidism. Thyroid hormones are essential for maintaining the health and regular growth cycle of hair follicles, including those on the eyelids. When these hormone levels are low, the follicles receive less stimulation, leading to thinning and loss of lashes—most noticeably at the outer edges. This differs from normal shedding, where individual lashes fall out and regrow as part of the natural cycle, with no significant thinning or pattern loss.

For example, an individual may notice their mascara applies unevenly, or that the outer portion of their upper and lower eyelids appears sparser than before. While occasional eyelash loss is common, persistent thinning or patchiness—especially at the edges—can be a red flag for underlying thyroid issues. According to the American Academy of Dermatology Association, this pattern of eyelash loss is often accompanied by thinning eyebrows, dry skin, or hair changes.

If you observe ongoing loss of your outer eyelashes, particularly when combined with other symptoms of hypothyroidism, it’s important to bring this up with your healthcare provider. Early recognition and treatment can help restore normal hair growth and overall health.

38. Hoarse or Deepened Voice

A hoarse or deepened voice is a notable manifestation of hypothyroidism, resulting from changes in the tissues around the vocal cords. Low thyroid hormone levels can cause swelling and thickening of the vocal cords and surrounding tissues, sometimes due to fluid retention (myxedema) or an enlarged thyroid gland (goiter) pressing on the larynx. This leads to a voice that may sound hoarse, rough, deeper, or even raspy—distinct from the temporary hoarseness that follows a cold, allergies, or excessive use of the voice.

For example, a person who once had a clear, higher-pitched voice may notice their speech becoming deeper and more gravelly over several weeks or months. Friends or colleagues might comment on the noticeable change, or the individual may find it more difficult to project their voice in conversation. According to the Mount Sinai Health Library, persistent changes in voice quality can be a sign of hypothyroidism, especially if they occur alongside other symptoms like neck swelling or fatigue.

If you experience ongoing hoarseness or deepening of your voice that does not resolve within a few weeks, it’s important to seek medical evaluation. Persistent voice changes may point to thyroid dysfunction or other treatable conditions.

39. Increased Risk of Infection

Hypothyroidism can increase susceptibility to infections by weakening the immune response. Thyroid hormones play a vital role in supporting the activity of white blood cells and maintaining the integrity of mucous membranes—both crucial for defending against viruses, bacteria, and other pathogens. When hormone levels are low, the immune system’s efficiency is compromised, making it harder for the body to mount a rapid and effective defense.

For example, someone with hypothyroidism may find that they catch colds or respiratory infections more often, or that minor illnesses linger longer than usual before clearing up. According to a study cited in the Journal of Immunology Research, untreated hypothyroidism is associated with a higher frequency of infections, including sinusitis, bronchitis, and urinary tract infections.

If you notice that you are experiencing frequent bouts of infection, or that ordinary illnesses take an unusually long time to resolve, it is important to discuss these patterns with your healthcare provider. Persistent or recurrent infections, especially when accompanied by other symptoms of hypothyroidism, may indicate compromised thyroid function and warrant further evaluation and management.

40. Numbness or Tingling in Extremities

Numbness or tingling in the hands, feet, fingers, or toes is a neurological symptom that can arise from untreated hypothyroidism. When thyroid hormone levels are low, fluid retention and tissue swelling may compress peripheral nerves, disrupting normal nerve signaling. This effect is sometimes compounded by slowed metabolism, which can impair the health and function of nerve cells over time.

For instance, someone may wake up with “pins and needles” sensations in their hands or notice episodes of numbness while typing, driving, or performing everyday tasks. These sensations might resolve with movement but tend to recur and can become more persistent as hypothyroidism progresses. According to the Hormone Health Network, these neurological symptoms may also be associated with carpal tunnel syndrome or general muscle weakness.

If you experience frequent or ongoing numbness, tingling, or loss of sensation in your extremities—especially if these symptoms are paired with other signs like swelling, muscle weakness, or fatigue—it is important to seek medical evaluation. Persistent nerve symptoms warrant investigation, as they may indicate hypothyroidism or another treatable underlying condition.

41. Decreased Sense of Taste or Smell

Decreased sense of taste (hypogeusia) or smell (hyposmia) is a lesser-known but possible symptom of hypothyroidism. Thyroid hormones are necessary for the maintenance and function of sensory nerves, and when hormone levels are low, the pathways that transmit taste and smell signals to the brain can become impaired. This sensory loss is often gradual and may go unnoticed until it begins to affect daily enjoyment of food or the ability to detect odors in the environment.

Unlike the sudden loss of taste and smell seen with viral infections like COVID-19 or sinus congestion from allergies, hypothyroidism-related changes typically develop slowly and persist over time. For example, a person may realize that their favorite meals seem bland, or that they have trouble detecting fragrances, smoke, or spoiled food. According to the Indian Journal of Endocrinology and Metabolism, these sensory changes often improve with thyroid hormone replacement therapy.

If you notice a gradual or persistent reduction in your sense of taste or smell—particularly if accompanied by other symptoms of hypothyroidism such as fatigue, dry skin, or weight gain—it’s important to discuss this with your healthcare provider. Early recognition can help lead to timely diagnosis and management.

42. Weakness During Exercise

Weakness during exercise is a common but often underappreciated symptom of hypothyroidism. Low thyroid hormone levels lead to reduced energy production in muscle cells, decreased oxygen utilization, and impaired removal of metabolic waste products. As a result, individuals may experience early fatigue, muscle cramps, and an inability to sustain physical effort at their usual levels.

For example, a person who previously enjoyed jogging or attending fitness classes might find themselves struggling to complete a warm-up or feeling noticeably weak after only a short period of activity. Everyday activities such as climbing stairs, carrying groceries, or engaging in recreational sports may become more challenging and less enjoyable. According to the Hormone Health Network, exercise intolerance and muscle weakness are hallmark symptoms of an underactive thyroid, often improving with appropriate thyroid hormone replacement.

If you notice a new or persistent decline in your exercise endurance, or find yourself unusually weak or short of breath during physical activity, it’s important to pay attention—especially if these changes occur alongside other hypothyroid symptoms such as fatigue, weight gain, or joint pain. Discussing these changes with your healthcare provider can help identify underlying thyroid dysfunction.

43. Decreased Hearing

Decreased hearing is a rare but recognized symptom associated with hypothyroidism. Thyroid hormones are important for the normal function of nerves and blood vessels in the ear. When these hormone levels are insufficient, fluid retention, slowed nerve conduction, and changes in the microcirculation of the inner ear can all contribute to hearing impairment. This can manifest as difficulty following conversations, needing higher volumes on devices, or experiencing a sense of muffled hearing.

For example, an individual might notice they frequently ask others to repeat themselves, have trouble distinguishing speech in noisy environments, or experience gradual worsening of hearing in one or both ears. According to the Indian Journal of Endocrinology and Metabolism, hearing loss in hypothyroidism can present as conductive, sensorineural, or mixed types, and may improve with proper thyroid treatment.

If you detect new or worsening hearing loss without obvious cause—particularly when accompanied by additional signs of hypothyroidism such as fatigue, weight gain, or dry skin—it is worth discussing thyroid screening with your healthcare provider. Early identification and management of thyroid dysfunction can sometimes reverse or halt the progression of hearing changes.

44. Changes in Taste Preferences

Changes in taste preferences can be a subtle yet telling sign of hypothyroidism. Thyroid hormones influence nerve signaling and cellular turnover in the taste buds, and a deficiency can alter how flavors are perceived. Unlike the occasional shift in food cravings or preferences due to seasonal changes, mood, or diet, hypothyroidism-related taste changes are often persistent and may not have an obvious explanation.

For example, a person who once enjoyed sweet foods might develop a preference for salty or bland foods, or may find certain flavors less appealing or even unpleasant. Meals that were once favorites may start to taste different, leading to reduced enjoyment during eating. According to the Indian Journal of Endocrinology and Metabolism, altered taste perception and preferences can be associated with hypothyroidism and may improve with thyroid hormone replacement therapy.

If you notice that your taste preferences have changed significantly and persistently—especially if these changes are not associated with illness, medication, or other dietary factors—it may be worthwhile to track these patterns and discuss them with your healthcare provider. Persistent changes in taste, particularly when combined with other symptoms, can be an important clue to underlying thyroid dysfunction.

45. Menstrual Irregularities (Men)

While men do not experience menstrual cycles, hypothyroidism can still cause significant hormonal changes that affect male reproductive health. Low thyroid hormone levels disrupt the balance of sex hormones, particularly testosterone, which may lead to symptoms such as reduced libido, erectile dysfunction, infertility, and even changes in breast tissue (gynecomastia). These hormonal imbalances can mirror some of the reproductive disturbances seen in women, though in men they present differently.

For example, a man with untreated hypothyroidism might notice a decrease in sexual desire, difficulties achieving or maintaining an erection, or reduced fertility despite regular attempts at conception. In some cases, subtle changes such as breast tenderness or swelling may also occur. According to the Indian Journal of Endocrinology and Metabolism, hypothyroidism in men is associated with a variety of reproductive and sexual dysfunctions, which may improve with appropriate thyroid hormone replacement therapy.

If you are male and experience persistent changes in sexual function, fertility, or notice breast tissue changes—especially in conjunction with other symptoms like fatigue, weight gain, or mood changes—it is important to discuss these concerns with your healthcare provider. Such changes can be a sign of underlying thyroid dysfunction that warrants evaluation.

46. Delayed Reflexes

Delayed reflexes are a well-documented neurological sign of hypothyroidism and can be particularly evident during a physical examination. Thyroid hormones are crucial for normal nerve conduction, ensuring that signals between nerves and muscles travel rapidly and efficiently. When hormone levels are low, these signals slow down, resulting in delayed muscle responses after a tendon is tapped—a phenomenon most commonly observed in the Achilles tendon, where the foot’s return to its resting position is noticeably sluggish.

In contrast to normal reflexes, where the muscle quickly contracts and then relaxes, delayed reflexes present as a slow or drawn-out movement following stimulation. For example, during a routine checkup, a healthcare provider may notice that your ankle reflex is slower than expected, even if you haven’t noticed any symptoms yourself. According to the National Center for Biotechnology Information (NCBI), this neurological sign is classic for hypothyroidism and can help differentiate it from other conditions.

If you become aware of changes in your physical responses—such as feeling slower when reacting to sudden movements or if your provider notes sluggish reflexes—it’s helpful to track these changes over time. Persistent delayed reflexes, especially with other hypothyroid symptoms, should prompt thorough evaluation.

47. Decreased Sweating

Decreased sweating is a notable symptom of hypothyroidism, resulting from the body’s slowed metabolic rate and reduced energy production. Thyroid hormones play a central role in regulating temperature and stimulating sweat glands. When these hormone levels are low, not only does the core body temperature drop, but the drive to produce sweat diminishes as well. This leads to noticeably less perspiration, particularly during activities or in environments that would normally cause sweating.

For example, a person may observe that they barely sweat during exercise classes or on hot summer days, even while others around them are perspiring heavily. This reduction in sweating stands in contrast to the normal experience where physical activity or heat leads to obvious dampness on the skin. According to the MSD Manuals, reduced or absent sweating is often accompanied by other symptoms such as dry skin and cold intolerance.

If you consistently notice less perspiration than usual, especially during exercise or exposure to heat, it’s important to pay attention—particularly if this change is new or accompanied by other signs of hypothyroidism. Bringing up these observations with your healthcare provider can facilitate earlier diagnosis and treatment.

48. Anemia

Anemia, or a low red blood cell count, can develop as a complication of hypothyroidism. Thyroid hormones are essential for the production of erythropoietin—a hormone made in the kidneys that stimulates red blood cell creation in the bone marrow. When thyroid hormone levels are low, this process slows, leading to a reduced number of circulating red blood cells. Additionally, hypothyroidism may impair the absorption of nutrients such as iron, folate, or vitamin B12, further contributing to anemia.

For example, someone with untreated hypothyroidism might experience persistent fatigue, weakness, pale skin, or shortness of breath even with mild exertion. Blood tests could reveal lower-than-normal hemoglobin or hematocrit levels. According to the Indian Journal of Endocrinology and Metabolism, anemia is a frequently overlooked but reversible cause of fatigue in people with hypothyroidism, and it often improves with appropriate thyroid hormone replacement therapy.

If you notice ongoing or unexplained fatigue, especially if it is accompanied by pallor or exercise intolerance, it’s important to discuss the possibility of anemia with your healthcare provider. Identifying and treating hypothyroidism-related anemia can significantly improve your energy and quality of life.

49. Swelling Around the Eyes

Swelling around the eyes, known as periorbital edema, is a visible sign often associated with hypothyroidism. This swelling occurs when low thyroid hormone levels cause fluid retention and accumulation in the soft tissues surrounding the eyes. Unlike the puffiness from allergies, which is usually accompanied by itching, redness, or watery eyes and tends to fluctuate throughout the day, hypothyroid-related swelling is typically persistent and may be most noticeable in the morning upon waking.

For example, a person may observe that their eyelids appear heavy, puffy, or swollen, and that the swelling does not resolve with allergy medication or over-the-counter remedies. According to the Mayo Clinic, periorbital edema can be one of the first physical clues to an underactive thyroid, especially if it develops gradually and is accompanied by other signs such as facial puffiness, dry skin, or fatigue.

If you notice persistent swelling around your eyes—especially if it is not related to a known allergy or resolves with rest—it is important to discuss these changes with your healthcare provider. Early recognition can help identify hypothyroidism and prevent further complications.

50. Delayed Deep Tendon Reflexes

Delayed deep tendon reflexes are a classic neurologic sign associated with hypothyroidism. These reflexes are tested by tapping tendons—such as the Achilles or patellar tendon—with a reflex hammer and observing the speed and strength of the resulting muscle contraction and relaxation. In hypothyroidism, the relaxation phase of the reflex is notably slowed, meaning the muscle takes longer to return to its resting state after being stimulated. This occurs because low thyroid hormone levels reduce nerve conduction velocity and alter muscle fiber function.

For instance, during a routine physical examination, a healthcare provider may notice that when your Achilles tendon is tapped, your foot moves downward (plantarflexes) but then slowly returns to its original position, rather than snapping back quickly. According to the National Center for Biotechnology Information (NCBI), this delayed relaxation is a highly specific sign of hypothyroidism and may help differentiate it from other neurological or muscular conditions.

If you or your provider notice changes in your reflexes—such as sluggish or delayed responses—particularly in the context of other symptoms like fatigue, weight gain, or dry skin, it is important to pursue further thyroid evaluation. Reflex changes can be a significant clue in diagnosing hypothyroidism.

Conclusion

Recognizing the diverse and sometimes subtle signs of hypothyroidism is essential for maintaining long-term health and quality of life. While many symptoms may appear gradually or mimic other conditions, persistent changes—such as fatigue, weight gain, dry skin, or mood shifts—should not be ignored. Early screening and diagnosis can prevent complications and lead to effective management. If you experience ongoing or unexplained symptoms, consult with your healthcare provider for thyroid evaluation and appropriate care. Timely intervention can restore wellbeing and reduce the risk of more serious health issues. For more information, visit the American Thyroid Association or the NIDDK.

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