Hypothyroidism is often managed at the level of making TSH normal rather than making the person feel well. Those two outcomes aren't always the same thing. Book a consultation with Dr. Chhavi Bansal today.
What the Thyroid Does and What Goes Wrong
The thyroid is a butterfly-shaped gland at the base of the neck. Its primary job is producing thyroid hormones, T4 (thyroxine) and T3 (triiodothyronine), which regulate how every cell in the body produces and uses energy. When the thyroid underproduces, metabolism slows across the board.
The pituitary gland monitors thyroid hormone levels and releases TSH (thyroid-stimulating hormone) to signal the thyroid to produce more. When thyroid output is low, TSH goes up. This is why elevated TSH is the standard diagnostic marker for hypothyroidism.
But here's the thing: TSH reflects the pituitary's signal, not the actual hormone reaching your tissues. A person can have normal TSH and still have poor T3 at the cellular level if conversion is impaired. That's one of the most commonly missed pieces of the picture.
Symptoms of Hypothyroidism
The symptom pattern is broad because thyroid hormone affects every system. That's also why it gets missed or attributed to other causes.
The Hashimoto's Connection
Most people diagnosed with hypothyroidism in India have Hashimoto's thyroiditis as the underlying cause, whether or not their doctor has tested for it. Hashimoto's is an autoimmune condition where the immune system produces antibodies that attack thyroid tissue. Over months and years, this gradually destroys the gland's ability to produce hormone.
The reason this matters: if you have Hashimoto's, treating only the thyroid hormone deficiency is addressing the consequence, not the cause. The autoimmune attack continues. Antibody levels and the inflammatory load need attention alongside hormone levels. This is what changes the long-term trajectory.
Testing for anti-TPO and anti-thyroglobulin antibodies is straightforward and inexpensive. But it's not always ordered in routine thyroid testing. If you've never had your antibodies tested, that gap in information is worth addressing.
Why T4 Alone Often Isn't Enough
Standard thyroxine (levothyroxine) is T4. Your body then converts T4 to the active form, T3, which is what cells actually use. The conversion happens primarily in the liver, gut, and peripheral tissues via an enzyme called deiodinase.
In a significant proportion of people (particularly those with chronic stress, gut issues, inflammation, or selenium deficiency) this conversion is impaired. Instead of T4 converting to active T3, more of it converts to reverse T3 (rT3), an inactive form that actually blocks T3 receptors.
The result: TSH normalises on T4 medication. Free T4 looks fine. But free T3 is still low and the person still feels hypothyroid. Their doctor says the numbers are good. The patient feels unheard. This is an extremely common clinical pattern.
- TSH: the standard first test; elevated in hypothyroidism
- Free T4: circulating thyroxine; low in overt hypothyroidism
- Free T3: the active hormone; may be low even when T4 is normal
- Anti-TPO antibodies: elevated in Hashimoto's; identifies the autoimmune cause
- Anti-thyroglobulin antibodies: secondary Hashimoto's marker
- Reverse T3: elevated when conversion to active T3 is impaired
Nutritional Factors That Matter
Thyroid function depends on specific nutrients that are surprisingly commonly deficient in the Indian diet or population. Selenium is required for the deiodinase enzyme that converts T4 to T3. Iodine deficiency impairs hormone production at source. Iron deficiency anaemia impairs thyroid peroxidase, the enzyme needed to make thyroid hormone. Vitamin D deficiency is strongly associated with Hashimoto's and autoimmune thyroid disease generally. Zinc supports T3 receptor function.
None of these replace treatment, but a person who is selenium or iodine deficient and on thyroxine without correcting those deficiencies is missing a meaningful part of the picture.