Thyroid disorders are among the most common health conditions in India — and they are also among the most confused. Patients often come to me saying "I have thyroid" without knowing which type they have. Understanding the difference between hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) is essential — because they are opposite conditions requiring opposite treatments.
The Thyroid Gland: What Does It Do?
The thyroid is a small butterfly-shaped gland in your neck. It produces thyroid hormones (T3 and T4) that regulate your metabolism — essentially the speed at which your body runs. When the thyroid produces too little hormone, everything slows down. When it produces too much, everything speeds up.
Symptoms: Spot the Difference
Hypothyroid Symptoms — "Everything Slowing Down"
- Persistent fatigue and sluggishness even after full night's sleep
- Unexplained weight gain despite normal diet
- Hair thinning, hair fall, dry skin
- Feeling cold all the time (cold intolerance)
- Constipation
- Low mood, depression, brain fog
- Puffiness in the face — especially around the eyes
- In women: irregular or heavy periods
Hyperthyroid Symptoms — "Everything Speeding Up"
- Unexplained weight loss despite eating normally or more
- Rapid heartbeat / palpitations
- Tremors (shaky hands)
- Feeling hot all the time (heat intolerance)
- Anxiety, restlessness, irritability
- Diarrhoea or very frequent bowel movements
- Bulging eyes (in Graves' disease — the most common cause)
- Difficulty sleeping
🩺 Which Is More Common?
In India, hypothyroidism is far more common — particularly in women, and particularly after pregnancy. Hyperthyroidism is less common but more dramatic in its symptoms. Both require proper diagnosis with blood tests — symptoms alone are not sufficient.
The Blood Test: TSH, T3, T4 — What Do They Mean?
The most important blood test for thyroid function is the TSH (Thyroid Stimulating Hormone):
- TSH HIGH → Hypothyroid (pituitary is working harder to stimulate an underactive thyroid)
- TSH LOW → Hyperthyroid (pituitary is suppressed because too much hormone is circulating)
- TSH NORMAL → Thyroid is likely functioning normally
Free T3 and Free T4 are measured when the TSH is abnormal to understand the severity. Anti-TPO antibodies are measured to detect autoimmune thyroid disease (Hashimoto's or Graves').
Treatment Differences
Hypothyroidism is treated with synthetic thyroxine (levothyroxine) — a daily tablet taken on an empty stomach. Most patients need this for life, and TSH is monitored every 6 months once stable.
Hyperthyroidism is treated with anti-thyroid medications, and in some cases with radioactive iodine or surgery — depending on the cause and severity. This requires specialist assessment.
⚠️ Do Not Self-Diagnose or Self-Medicate
The treatment for hypothyroid and hyperthyroid are opposite. If you take thyroxine when you actually have hyperthyroidism, it can cause a cardiac emergency. Always get a proper diagnosis with blood tests before starting any thyroid medication.
Get Your Thyroid Tested in Kolkata
A simple TSH blood test is all it takes to screen for thyroid disease. Book a consultation with Dr. Chaurasia to discuss your symptoms and results.