Thyroid in India: why most of it is no longer about iodine

Every Indian family has someone 'on thyroid.' Around one in nine adults has an underactive thyroid — roughly five times the UK rate — and the reflex explanation is always the same: 'iodine ki kami.' That answer is a generation out of date.

India ran one of its quietest public-health successes, universal salt iodisation, and most of the country now gets enough iodine. The real driver today, especially in cities and especially in women, is the immune system slowly attacking the thyroid gland — a condition called Hashimoto's. It builds for years before a single blood test looks abnormal, which is why so many people feel 'off' long before anyone names it.

This page is about what the thyroid actually does, why the disease is mostly autoimmune now, what a TSH number really means, and the one daily habit that decides whether the pill even works.

• Who should read thisanyone told their thyroid is 'borderline,' anyone on levothyroxine who still feels tired, women planning a pregnancy, families with a thyroid history.
• What you will learnwhat TSH, T4 and anti-TPO mean, why timing the pill matters, and when 'normal' isn't normal.
• What you will not getdose numbers or a promise of an Ayurvedic cure.
• Time to read11 minutes.

Read this once. Every term on your report — and on this page — starts here.

The thyroid gland

A butterfly-shaped gland in the front of the neck. It sets the body's tempo: energy, heat, heart rate, digestion speed, mood, hair and skin.

T4 and T3

The two thyroid hormones. T4 is the storage form the gland mostly releases; the body converts it into T3, the active form that does the work inside every cell.

TSH

Thyroid-stimulating hormone, made by the pituitary, not the thyroid. It is the body's thermostat signal: when thyroid hormone runs low, TSH rises to push the gland harder. So a high TSH usually means an underactive thyroid — the opposite of what people expect.

Hashimoto's thyroiditis

An autoimmune disease in which the immune system makes antibodies that slowly destroy the thyroid. It is the main cause of an underactive thyroid in urban India.

Anti-TPO antibodies

The blood marker of that attack. If anti-TPO is positive, Hashimoto's is the reason — not iodine.

Subclinical hypothyroidism

The in-between stage: TSH is mildly high but T4 is still in range. Symptoms are vague, and whether to treat is genuinely debated.

Levothyroxine

The standard medicine — a synthetic copy of T4. It replaces the missing hormone; it does not cure the gland, and food blocks its absorption.

Hashimoto's is not a sudden event. It is a slow siege the body hides from you until late. Here is the sequence.

The cruelty of the disease is its timing. The damage is done in silence, and the label arrives only after years of feeling slightly wrong while holding a 'normal' report.

Two sets of numbers matter: how common this is, and how to read your own TSH.

How common it is in India

• About 11% of adults have hypothyroidism — roughly five times the UK rate.
• It is about four times more common in women than in men.
• Around 8% more sit in the subclinical stage.
• In a 2024 Delhi study, 75–80% of overt hypothyroid patients tested positive for anti-TPO — meaning autoimmune Hashimoto's, not iodine.
• About 14% of Indian pregnancies involve hypothyroidism, mostly subclinical.

One number to hold ontoa TSH of 4 can be called 'normal' by one lab and 'treat' by another. The number alone is not the diagnosis — antibodies, free T4 and your symptoms complete it.

Myth 1 — Thyroid trouble means low iodine.

In urban India it usually means the opposite kind of problem — autoimmune Hashimoto's. Most patients have enough iodine; their anti-TPO antibodies are the real story.

Myth 2 — Thyroid medicine makes you gain weight.

It is the untreated underactive thyroid that adds weight, by slowing metabolism. Correct replacement restores the normal tempo. The pill is neither a weight-loss nor a weight-gain drug.

Myth 3 — TSH is 4, so don't worry.

Maybe. But with clear symptoms, many endocrinologists treat above 2.5, and checking anti-TPO and free T4 gives the number meaning. 'Normal range' is not the same as 'optimal for you.'

Myth 4 — You can take levothyroxine any time.

No. Food, tea, coffee, calcium and iron cut its absorption by about a third. Taken with breakfast it never works fully — and doses get raised chasing a problem that is really about timing.

Myth 5 — Hashimoto's can be cured by Ayurveda or yoga.

There is no replicated evidence of reversal. Some steps may slow it, but the gland's destruction continues if hormone is not replaced.

Myth 6 — Surgery ends the thyroid problem.

Removing the gland causes lifelong hypothyroidism — you still need the daily pill, permanently.

Myth 7 — A thyroid nodule means cancer.

Most nodules are harmless. Only a small share are cancerous, and most of those are highly treatable. A scan and, if needed, a biopsy sort it out.

Not panic, and not folklore. A short, ordered set of moves around the actual mechanism.

See a doctor properly ifyou notice a new neck swelling or lump, trouble swallowing, a racing heart with weight loss, or symptoms that persist despite rising doses — that last one usually points to timing, not a bigger dose.

Follow one believable arc — it explains the disease better than any table.

The dismissal. Meera, 36, a teacher in Pune, is tired in a way sleep doesn't fix. Her weight creeps up, her hair thins, she feels cold when no one else does. Her TSH comes back 4.2. 'Normal,' she's told. Twice.

The real test. A year later, still unwell, she sees an endocrinologist who adds two tests her earlier reports never had: free T4 and anti-TPO. The antibodies are high. The diagnosis is Hashimoto's — her own immune system, not iodine, slowly switching the gland off. That 'normal' TSH had been the early, subclinical edge of it all along.

The pill that didn't work. She starts levothyroxine — and takes it with her morning chai, like a vitamin. Three months later she feels no better. The dose is raised. Still nothing.

The fix that did. A pharmacist mentions the timing. She moves the pill to an empty stomach, water only, thirty minutes before anything else. Within weeks the fog lifts — on the very dose that 'wasn't working.'

That is the whole lesson in one life: the right diagnosis needs the right tests, and the right medicine needs the right timing. Miss either, and you can feel ill for years with a 'normal' report in your hand.

Step back and the Indian thyroid story flips. The old picture — iodine deficiency, a problem of poor diets — has largely been solved by one of the country's quietest public-health wins, universal salt iodisation. What replaced it is subtler: an autoimmune disease of relative plenty, rising in cities and falling hardest on women.

This matters because almost everything about it is manageable, and cheap — levothyroxine costs about ₹40–80 a month. The failures are rarely about the medicine itself. They are about a lone TSH number standing in for a real diagnosis, and a pill swallowed with chai so it never fully works. Both are fixable in an afternoon.

The lesson is the one that runs through modern Indian health: the folklore is a generation behind the biology. 'Thyroid means iodine' was true for our grandparents; for us it usually means antibodies. Treating the new disease with the old story is how people stay tired for years.

The long-term shift is cultural — from a vague 'thyroid hai' that explains every symptom, to a sharper question: which thyroid problem, shown by which test, treated in which way. Get specific, and a condition that quietly shapes millions of Indian lives becomes one of the most controllable there is.