Top 10 Signs and Symptoms of Hypothyroidism: What to Watch For
Top 10 Signs and Symptoms of Hypothyroidism: What to Watch For
Hypothyroidism—also known as an underactive thyroid—occurs when the thyroid gland does not produce enough thyroid hormone. Because these hormones regulate metabolism, energy production, temperature, heart rate, digestion, and even mood, low thyroid levels can cause widespread symptoms that are often mistaken for normal aging.
Understanding the early signs is critical. Hypothyroidism is common, easy to miss, and highly treatable once diagnosed.
Below are the top 10 symptoms of hypothyroidism to watch for, based on established medical sources and current clinical understanding.
1. Persistent Fatigue and Low Energy
Fatigue is the most frequently reported symptom. Even with adequate sleep, individuals may feel drained or sluggish. With slowed metabolic activity, the body produces less cellular energy, leading to constant tiredness [1].
2. Unexplained Weight Gain or Difficulty Losing Weight
A reduced metabolic rate means the body burns fewer calories at rest. Many people with hypothyroidism experience gradual weight gain or find weight loss unusually difficult despite healthy habits [2].
3. Increased Sensitivity to Cold
Thyroid hormones help regulate body temperature. When levels drop, the body struggles to maintain warmth. Patients often notice cold hands and feet or feeling colder than those around them [3].
4. Dry Skin, Coarse Hair, and Hair Loss
Low thyroid function slows skin turnover and decreases natural oil production. This leads to dry, flaky skin, brittle hair, and sometimes noticeable hair thinning—especially along the outer eyebrows [4].
5. Puffiness and Swelling (Myxedema)
Advanced hypothyroidism can cause swelling in the face, hands, and feet. This puffiness, known as myxedema, results from changes in skin and tissue composition due to low thyroid hormone levels [1].
6. Constipation and Digestive Sluggishness
Thyroid hormones play a role in gut motility. When levels are low, digestion slows, leading to constipation, bloating, and abdominal discomfort [2].
7. Mood Changes, Depression, and Brain Fog
Declining thyroid function impacts neurotransmitters and cognitive performance. Patients may experience depression, slowed thinking, forgetfulness, or general mental cloudiness often referred to as “brain fog” [4].
8. Irregular or Heavy Menstrual Cycles (in Women)
Women with hypothyroidism may experience heavier periods, irregular cycles, or skipped menstruation. Hormonal imbalance can also contribute to fertility challenges [2].
9. Slow Heart Rate and Elevated Cholesterol
Thyroid hormones directly influence cardiovascular function. Low levels may result in a slower heart rate (bradycardia) and increased LDL (“bad”) cholesterol, raising long-term cardiovascular risk [4].
10. Muscle Aches, Pain, and Weakness
Many patients report general muscle stiffness, cramps, or weakness. Because metabolism slows, muscles receive less energy, making normal activities feel more strenuous [2].
When to See a Doctor
If you recognize several of these symptoms, it’s important to speak with a healthcare professional. A
simple blood test measuring TSH, Free T4, and sometimes Free T3 can confirm whether hypothyroidism is the cause.
The good news: Hypothyroidism is highly treatable. Most patients experience significant improvement once thyroid hormone levels are restored with medication.
Conclusion
Hypothyroidism can affect every system of the body, but the early signs are often subtle and easily overlooked. Recognizing the symptoms—fatigue, weight changes, cold sensitivity, mood shifts, digestive issues, and more—can lead to timely diagnosis and treatment. With proper care, individuals typically regain energy, metabolic balance, and improved quality of life.
Works Cited
American Thyroid Association. (n.d.). Hypothyroidism. Retrieved from https://www.thyroid.org/hypothyroidism/
Cleveland Clinic. (n.d.). Hypothyroidism (Underactive Thyroid): Symptoms & Treatment. Retrieved from https://my.clevelandclinic.org/health/diseases/12120-hypothyroidism
UCSF Health. (n.d.). Hypothyroidism. Retrieved from https://www.ucsfhealth.org/conditions/hypothyroidism
Medical News Today. (2025, May). 12 signs and symptoms of hypothyroidism (underactive thyroid). Retrieved from https://www.medicalnewstoday.com/articles/324535
Mayo Clinic. (n.d.). Hypothyroidism (Underactive Thyroid) Symptoms & Causes. Retrieved from https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284
