For the hypothyroidism Hashimoto's causes, the treatment is beautifully simple: replace the hormone your gland can no longer make. Levothyroxine — synthetic T4 — is cheap, once-daily, and lets most people feel completely normal. Getting the details right is what separates 'fine' from 'still struggling.'
Levothyroxine is synthetic T4, the exact hormone the thyroid makes; your body converts it to active T3 as needed. Full replacement is roughly 1.6 mcg per kg of body weight per day, but doctors start low in older or heart patients (25–50 mcg) and titrate up. A dose takes about 6–8 weeks to settle, so that's when TSH is rechecked. Most people do very well on T4 alone. Evidence ●●●●●
Levothyroxine is fussy about absorption: take it on an empty stomach 30–60 minutes before food (or at bedtime, 3+ hours after eating), and keep it well away from coffee, calcium, and iron — coffee within an hour can cut absorption by up to a third. Acid-reducing drugs (PPIs) and gut issues (celiac) also lower it. Stick to one brand; small differences matter. Evidence ●●●●○
The goal is to bring TSH into the normal range (many aim for the lower-middle, ~1–2.5, in younger adults; higher in the elderly). Crucially, over-treating — pushing TSH too low chasing symptoms — isn't harmless: it raises the risk of atrial fibrillation and bone loss. Optimise to feel well within a safe range, not below it. Evidence ●●●●○
Fix how you take the pill before changing the dose
The biggest fixable reason for a 'stubbornly high' TSH is how you take it: same brand, empty stomach, and separated from coffee, calcium, and iron. Nail that before anyone reaches for a higher dose.
The Hashimoto’s Guide