One more question, if you get tired/lethargic on 12.5 mcg would that imply that you are still using too much for your body? I started this week at that dose and feel very, very lethargic/brainfog, etc. I was cutting for one more week and starting next week I shall resume a higher caloric intake so that may be the issue.
i doubt 12.5mcg of t3 will d anything at all. i think its possible that maybe your body realises that your ingesting t3, so it slowed down its own output, but you arent taking enough to compensate, so you actuyally have less t3.
t3 should not make you lethargic, normally the only thing you will "feel" is increased tolerance to the cold and alot of sweating when its hot.
how are you taking the t3?? t3 has a very unstable absorbtion %. it ranges from 30-60% if i recall correctly. and you cant take any calcium/magnesium within a few hours of dosing. in order to get the full absorbtion you need to take it by itself, first thing in the morning, with plain water only, and then wait at least 30 mins, preferably an hour, before eating anything.
you might be able to "feel" the t3 absorbing in your stomach/liver after about 45 mins after taking it. it may feel like a slight stomach pain, or similar to liver toxicity pains you might have felt during a long course of orals. if you feel that, then its ok for you to eat.
25mcg is the usual replacement doseage given to people. i wouldnt use less than that.