12 Common Hypothyroidism Symptoms: Signs of Underactive Thyroid

Hypothyroidism, commonly known as underactive thyroid, is a condition where your thyroid gland doesn’t produce enough thyroid hormones to meet your body’s needs. These hormones play a crucial role in regulating metabolism, energy production, and numerous bodily functions. When thyroid hormone levels are too low, your body’s processes begin to slow down, leading to a wide range of symptoms that can significantly impact your quality of life.

The thyroid gland, a small butterfly-shaped organ located at the base of your neck, may seem insignificant, but its impact on your overall health is profound. Understanding the symptoms of hypothyroidism is essential for early detection and proper management. Many people live with undiagnosed hypothyroidism for years because the symptoms develop gradually and can be mistaken for other conditions or simply attributed to aging or stress.

In this comprehensive guide, we’ll explore the most common signs of hypothyroidism, what causes this condition, and answer frequently asked questions to help you better understand this widespread thyroid disorder.

1. Persistent Fatigue and Low Energy

One of the hallmark symptoms of hypothyroidism is overwhelming fatigue that doesn’t improve with rest. People with an underactive thyroid often describe feeling exhausted even after a full night’s sleep. This isn’t just ordinary tiredness—it’s a profound lack of energy that makes even simple daily tasks feel challenging.

The fatigue occurs because thyroid hormones help regulate how your body converts food into energy. When thyroid hormone levels are low, your metabolism slows down, and your cells don’t receive the energy they need to function optimally. You might find yourself:

• Needing more sleep than usual
• Struggling to get out of bed in the morning
• Feeling drained by early afternoon
• Lacking the energy for exercise or social activities
• Experiencing difficulty concentrating due to exhaustion

This persistent fatigue often interferes with work performance, relationships, and overall quality of life, making it one of the most debilitating symptoms of hypothyroidism.

2. Unexplained Weight Gain

Unexpected weight gain is another classic symptom of hypothyroidism. Despite maintaining your usual diet and exercise routine, you may notice the numbers on the scale creeping upward. This weight gain typically occurs gradually and can be frustrating because it seems resistant to conventional weight loss efforts.

The weight gain associated with hypothyroidism happens because your metabolism slows down when thyroid hormone production decreases. Your body burns fewer calories at rest, and you may also experience increased water retention. The weight gain is usually moderate—typically between 5 to 10 pounds—though it can be more substantial in severe cases.

Additionally, the fatigue that accompanies hypothyroidism may make you less active, further contributing to weight gain. Many people with underactive thyroid find that their weight doesn’t respond to diet and exercise until their thyroid hormone levels are properly balanced.

3. Increased Sensitivity to Cold

Feeling cold when others around you are comfortable is a telltale sign of hypothyroidism. People with an underactive thyroid often complain about feeling chilly, even in warm environments. You might find yourself:

• Wearing layers of clothing when others are in short sleeves
• Having cold hands and feet constantly
• Needing extra blankets at night
• Feeling uncomfortable in air-conditioned spaces
• Struggling to warm up even after physical activity

This heightened sensitivity to cold occurs because thyroid hormones help regulate body temperature. When hormone levels are low, your body produces less heat, and your metabolism slows down, making it harder to maintain normal body temperature. This symptom is particularly noticeable in your extremities, where blood flow may be reduced.

4. Dry Skin and Hair Changes

Hypothyroidism can have significant effects on your skin and hair. Your skin may become noticeably dry, rough, and flaky, regardless of how much moisturizer you apply. The dryness can be particularly severe on your elbows, knees, and the soles of your feet.

Hair changes are equally common and distressing. You may notice:

• Hair becoming dry, brittle, and coarse in texture
• Increased hair loss or thinning, particularly on the scalp
• Loss of the outer third of your eyebrows
• Hair that breaks easily and loses its natural shine
• Slower hair growth

These changes occur because thyroid hormones play a crucial role in the growth and maintenance of skin cells and hair follicles. When hormone levels are inadequate, cell turnover slows down, leading to dry skin and weakened hair structure. The reduced blood flow to the skin and scalp that accompanies hypothyroidism further contributes to these symptoms.

5. Muscle Weakness and Joint Pain

Many people with hypothyroidism experience various musculoskeletal symptoms that can significantly impact their daily activities. Muscle weakness is common, particularly in the larger muscle groups of your arms and legs. You might notice difficulty climbing stairs, lifting objects, or rising from a seated position.

Joint pain and stiffness are also frequent complaints, often affecting multiple joints throughout the body. The pain may be accompanied by:

• Stiffness, especially in the morning
• Swelling around the joints
• Reduced range of motion
• Muscle aches and tenderness
• Cramping, particularly at night

The muscle and joint problems associated with hypothyroidism occur because thyroid hormones are essential for muscle metabolism and maintenance. Low hormone levels can lead to fluid accumulation in joints and muscles, causing swelling and discomfort. Some people may also develop carpal tunnel syndrome due to fluid retention compressing the median nerve in the wrist.

6. Depression and Mood Changes

The impact of hypothyroidism on mental health is significant and often underestimated. Depression is one of the most common psychological symptoms, affecting a substantial number of people with underactive thyroid. This isn’t just feeling sad occasionally—it can be persistent, debilitating depression that affects all aspects of life.

Mental and emotional symptoms may include:

• Persistent sadness or feeling down
• Loss of interest in activities you once enjoyed
• Irritability and mood swings
• Anxiety and nervousness
• Difficulty feeling pleasure or happiness
• Social withdrawal

Thyroid hormones directly affect brain chemistry and the production of neurotransmitters like serotonin, which regulate mood. When thyroid hormone levels are low, neurotransmitter function can be disrupted, leading to depression and other mood disorders. It’s worth noting that in some cases, depression may be the primary or only symptom of hypothyroidism, which is why thyroid function should be evaluated in people with depression that doesn’t respond well to standard treatments.

7. Cognitive Impairment and Brain Fog

Cognitive symptoms are frustrating manifestations of hypothyroidism that can affect your work performance and daily functioning. Many people describe experiencing “brain fog”—a sense of mental cloudiness that makes thinking clearly difficult.

Specific cognitive symptoms include:

• Difficulty concentrating and focusing on tasks
• Memory problems, particularly short-term memory
• Slower mental processing and reaction times
• Trouble finding the right words when speaking
• Decreased mental sharpness and clarity
• Difficulty making decisions

These cognitive changes occur because thyroid hormones are crucial for brain function and the maintenance of neural connections. An underactive thyroid can slow down brain metabolism, affecting memory formation, information processing, and overall mental acuity. The severity of cognitive symptoms often correlates with the degree of thyroid hormone deficiency, and these symptoms typically improve once thyroid hormone levels are restored to normal.

8. Constipation and Digestive Issues

Digestive problems, particularly constipation, are common in people with hypothyroidism. The slowed metabolism that characterizes an underactive thyroid also affects your digestive system, causing food to move more slowly through your intestinal tract.

You may experience:

• Chronic constipation that doesn’t respond well to dietary changes
• Infrequent bowel movements
• Hard, difficult-to-pass stools
• Bloating and abdominal discomfort
• Reduced appetite despite weight gain

The constipation associated with hypothyroidism occurs because thyroid hormones help regulate the contraction of the muscles in your intestinal walls. When hormone levels are low, these contractions slow down, and the normal movement of digestive contents through the intestines becomes sluggish. This can lead to increased water absorption from the stool, making it harder and more difficult to pass.

9. Menstrual Irregularities in Women

Hypothyroidism symptoms in females often include significant changes to the menstrual cycle. Thyroid hormones play an important role in regulating reproductive hormones, so an underactive thyroid can cause various menstrual disturbances.

Women with hypothyroidism may experience:

• Heavier than normal menstrual bleeding (menorrhagia)
• More frequent periods
• Longer menstrual periods
• More severe menstrual cramps
• Irregular cycle lengths
• In some cases, absent or very light periods

These menstrual changes can also be accompanied by worsening premenstrual syndrome (PMS) symptoms. Additionally, hypothyroidism can affect fertility, making it more difficult to conceive. Women who are trying to become pregnant or who have experienced recurrent miscarriages should have their thyroid function evaluated, as untreated hypothyroidism can complicate pregnancy.

10. Slowed Heart Rate

Cardiovascular symptoms are important signs of hypothyroidism that shouldn’t be ignored. A slower than normal heart rate, known as bradycardia, is common in people with underactive thyroid. While a normal resting heart rate typically ranges from 60 to 100 beats per minute, people with hypothyroidism may have rates below 60.

Other cardiovascular symptoms may include:

• Feeling like your heart is beating weakly or slowly
• Reduced exercise tolerance
• Shortness of breath with minimal exertion
• Dizziness or lightheadedness
• Elevated cholesterol levels

Thyroid hormones directly affect heart function, influencing heart rate, cardiac output, and blood vessel relaxation. When thyroid hormone levels are insufficient, the heart may beat more slowly and less forcefully. Over time, untreated hypothyroidism can contribute to elevated cholesterol levels and increased risk of heart disease, making it important to address this symptom promptly.

11. Hoarse Voice and Throat Discomfort

Changes in your voice and sensations in your throat can be indicators of hypothyroidism. Many people develop a hoarse, husky, or deeper voice than usual. This occurs because the thyroid gland itself may become enlarged (a condition called goiter), or because of swelling in the vocal cords and surrounding tissues.

Throat-related symptoms include:

• Persistent hoarseness without other signs of illness
• A feeling of fullness or pressure in the throat
• Difficulty swallowing (dysphagia)
• Visible swelling at the base of the neck
• Changes in voice quality or pitch

The voice changes occur due to fluid retention in the tissues around the larynx and vocal cords. In cases where the thyroid gland is significantly enlarged, it may physically press on the throat structures, causing discomfort and affecting voice production. If you notice persistent hoarseness or throat swelling, it’s important to have your thyroid evaluated.

12. Puffy Face and Swelling

Fluid retention is a characteristic feature of hypothyroidism, often manifesting as facial puffiness and swelling in various parts of the body. The puffiness is particularly noticeable around the eyes, giving a swollen or bloated appearance that’s especially prominent in the morning.

Common areas affected by swelling include:

• Around the eyes, particularly the lower eyelids
• Cheeks and face, creating a rounded appearance
• Hands, making rings feel tight
• Feet and ankles
• The tongue, which may appear enlarged with indentations from teeth

This type of swelling, called myxedema, occurs because hypothyroidism causes a buildup of protein and other substances in the tissues, which attracts and retains water. Unlike the swelling from other causes, myxedema has a distinctive quality—when you press on the swollen area, it doesn’t leave an indentation (non-pitting edema). The facial puffiness combined with other symptoms like dry skin and hair loss can significantly affect a person’s appearance and self-esteem.

What Causes Hypothyroidism?

Understanding what causes hypothyroidism is important for recognizing risk factors and seeking appropriate care. Several conditions and factors can lead to an underactive thyroid:

Autoimmune Disease (Hashimoto’s Thyroiditis): This is the most common cause of hypothyroidism in developed countries. Hashimoto’s thyroiditis occurs when your immune system mistakenly attacks the thyroid gland, gradually destroying its ability to produce hormones. This autoimmune condition tends to run in families and is more common in women than men.

Thyroid Surgery: Surgical removal of all or part of the thyroid gland, whether for thyroid cancer, nodules, or hyperthyroidism, can result in reduced or absent thyroid hormone production. People who have had thyroid surgery typically require lifelong thyroid hormone management.

Radiation Therapy: Radiation treatment for head and neck cancers or radioactive iodine therapy used to treat hyperthyroidism can damage the thyroid gland, leading to hypothyroidism. The risk increases with the radiation dose and the extent of thyroid tissue exposed.

Medications: Several medications can interfere with thyroid hormone production. Lithium, used to treat certain psychiatric disorders, is well-known for potentially causing hypothyroidism. Other medications including amiodarone (for heart rhythm problems), interferon alpha (for certain cancers and hepatitis), and some immunotherapy drugs can also affect thyroid function.

Iodine Imbalance: Iodine is essential for thyroid hormone production. Both too little and too much iodine can cause hypothyroidism. While iodine deficiency is rare in countries where salt is iodized, it remains a significant cause of hypothyroidism worldwide. Excessive iodine intake from supplements or certain medications can also impair thyroid function.

Pituitary Disorders: The pituitary gland produces thyroid-stimulating hormone (TSH), which signals the thyroid to produce hormones. Damage to the pituitary gland from tumors, surgery, or radiation can reduce TSH production, leading to secondary hypothyroidism.

Congenital Hypothyroidism: Some babies are born with an absent or improperly developed thyroid gland, or with defects in thyroid hormone production. Newborn screening programs in many countries help identify these cases early to prevent developmental problems.

Pregnancy and Postpartum Period: Some women develop thyroid inflammation (thyroiditis) during or after pregnancy. Postpartum thyroiditis typically occurs within the first year after delivery and may cause temporary hypothyroidism that can become permanent in some cases.

Prevention Strategies

While not all cases of hypothyroidism can be prevented, especially those caused by autoimmune conditions or genetic factors, there are steps you can take to support thyroid health and reduce your risk:

Ensure Adequate Iodine Intake: Maintain appropriate iodine levels by using iodized salt and consuming iodine-rich foods like seafood, dairy products, and eggs. However, avoid excessive iodine supplementation unless recommended by a healthcare provider, as too much iodine can also cause thyroid problems.

Manage Stress: Chronic stress can affect thyroid function and overall hormonal balance. Practice stress-reduction techniques such as meditation, yoga, regular exercise, and adequate sleep to support your endocrine system.

Avoid Exposure to Toxins: Limit exposure to environmental toxins and chemicals that can disrupt thyroid function, including certain pesticides, heavy metals, and industrial chemicals. Choose organic produce when possible and use natural cleaning products.

Eat a Balanced Diet: Consume a nutrient-rich diet that includes selenium (found in Brazil nuts, fish, and eggs), zinc, and vitamins D and B12, all of which support thyroid health. Include plenty of fruits, vegetables, whole grains, and lean proteins.

Regular Health Screenings: If you have risk factors for hypothyroidism—such as a family history of thyroid disease, autoimmune conditions, or if you’re a woman over 60—discuss thyroid screening with your doctor. Early detection allows for prompt management before symptoms become severe.

Be Cautious with Goitrogenic Foods: While they shouldn’t be avoided entirely, be aware that certain raw foods like cruciferous vegetables (broccoli, cauliflower, cabbage) contain compounds that can interfere with thyroid hormone production when consumed in very large quantities. Cooking these vegetables reduces this effect.

Monitor Medication Effects: If you’re taking medications known to affect thyroid function, such as lithium or amiodarone, work with your healthcare provider to monitor your thyroid levels regularly.

Frequently Asked Questions

Can hypothyroidism symptoms differ between men and women?

Yes, while many symptoms are similar, women are more likely to experience menstrual irregularities, fertility issues, and complications during pregnancy. Men may more commonly notice decreased libido, erectile dysfunction, and muscle mass loss. However, fatigue, weight gain, and cold intolerance affect both sexes equally.

How long does it take for hypothyroidism symptoms to develop?

Hypothyroidism typically develops gradually over months or years. Symptoms may be so subtle initially that they’re easily dismissed or attributed to other causes like aging or stress. This slow progression is why many people don’t realize they have a thyroid problem until symptoms become more pronounced.

Can you have hypothyroidism with normal TSH levels?

While TSH (thyroid-stimulating hormone) is the primary screening test, some people have subclinical hypothyroidism with slightly elevated TSH but normal thyroid hormone levels. Others may have symptoms with TSH levels in the “normal” range but not optimal for their body. Comprehensive thyroid testing including free T4 and free T3 levels may be necessary for accurate diagnosis.

Is hypothyroidism more common in certain age groups?

Hypothyroidism can occur at any age, but it becomes more common as people get older, particularly in women over 60. However, it can also affect children, adolescents, and young adults. The risk increases with age, and women are 5 to 8 times more likely to develop hypothyroidism than men.

Can stress cause hypothyroidism?

While stress alone doesn’t directly cause hypothyroidism, chronic stress can affect thyroid function and may contribute to the development of autoimmune thyroid conditions. Stress impacts the hypothalamic-pituitary-thyroid axis and can exacerbate existing thyroid problems or unmask subclinical hypothyroidism.

Are hypothyroidism symptoms reversible?

Most symptoms of hypothyroidism are reversible with appropriate management. Once thyroid hormone levels are restored to normal ranges, many people experience significant improvement in their symptoms. However, the underlying cause typically remains, meaning long-term management is usually necessary to keep symptoms at bay.

Can diet alone manage hypothyroidism?

While a healthy diet supports overall thyroid function, diet alone cannot typically manage clinical hypothyroidism. Most people require thyroid hormone supplementation as directed by their healthcare provider. However, proper nutrition can help optimize thyroid function and improve how you respond to treatment.

When should I see a doctor about possible hypothyroidism symptoms?

You should consult a healthcare provider if you experience multiple symptoms of hypothyroidism, especially if they persist or worsen over time. It’s particularly important to seek medical attention if you have risk factors such as a family history of thyroid disease, previous thyroid problems, or other autoimmune conditions. A simple blood test can determine if hypothyroidism is causing your symptoms.

Can hypothyroidism go away on its own?

Most forms of hypothyroidism are permanent and require ongoing management. However, some cases of thyroiditis (thyroid inflammation) can cause temporary hypothyroidism that resolves on its own. Postpartum thyroiditis, for example, may cause temporary thyroid dysfunction that improves within a year, though some women develop permanent hypothyroidism.

Does hypothyroidism affect life expectancy?

When properly managed, hypothyroidism should not significantly affect life expectancy. However, untreated or poorly controlled hypothyroidism can lead to serious complications including heart disease, nerve damage, infertility, and in severe cases, a life-threatening condition called myxedema coma. This is why diagnosis and appropriate management are so important.

References:

• Mayo Clinic – Hypothyroidism (underactive thyroid)
• National Institute of Diabetes and Digestive and Kidney Diseases – Hypothyroidism
• American Thyroid Association – Hypothyroidism
• Endocrine Society – Hypothyroidism
• MedlinePlus – Hypothyroidism
• NHS – Underactive thyroid (hypothyroidism)