Thyroid inactive after T3

[Romany]

Does anyone know whether taking T3 makes your own thyroid totally inactive ? As I understand your own thyroid, even when under active still releases a little thyroid Hormone so I'm wondering if by taking T3 the thyroid will stop releasing any Hormone at all

[humanbean]

If you took enough thyroid hormone of any kind, not just T3, you could suppress all activity of the thyroid. If TSH was so low as to be practically non-existent then the only thyroid hormone you would have in your body would be what you were supplying artificially.

It is true that, for some people, taking T3 (or NDT which contains T3) reduces TSH quite dramatically, more so than T4 would.

I should add that the propensity of T3 to suppress TSH so much for some people is very annoying. People could end up still feeling under-dosed and yet TSH is rock bottom.

[greygoose]

As HB said, BUT... if you stopped your meds for some reason - ran out of them or something - eventually, your thyroid would go back to making as much hormone as it was capable of making - if that's what you're worried about.

As HB said, taking T3 can suppressed the TSH, which will mean that the thyroid won't get any stimulation to make hormone, but when you're on T3, you shouldn't dose by the TSH. The important number is the FT3.