Originally Posted by fatiguegalore
Cytomel is pure T3. I was once on cytomel, also to help with depression. It ended up having the effect of driving down my T4 levels and making me feel worse.
Does driving down T4 make one feel worse as a result of total thyroid activity being lower, or because T4 has activity independent of its conversion to T3? I could never quite understand that.
Also, one other question. If someone is hypo and takes a smaller than therapeutic dosage for a prolonged period, does supression of endogenous thyroid through feedback inhibition end lead to lower total levels of T3 and/or T4 than would occur without treatment at all? That is, does thyroid always suppress and replace, or sometimes just supplement, the body's own thyroid production?
I'll get my levels checked in any case. Thanks for the prompt replies.