Isn't this flat look purely dose dependent? Someone like Smoof who just uses replacement dose at 12.5mcg because of all the gh/tren he is using is alot different than using 50+mcg. If you are on gear and not dieting/cutting carbs (in a caloric deficit) is 25mcg t3 going to leave you flat?
25mcg will do nothing but suppress your thyroid near fully as it's a replacement dosage, essentially the equivalent to an average person's thyroid output (caveat being people have different functioning thyroids and thyroid meds are all different potencies and bioavailability).
tren can, and does suppress the thyroid, likewise all stimulants do to some extent as well, so it's not entirely a waste for bodybuilders whom are running the cocktail of drugs they normally do. i'm not sure if a person's body signaling to lower TSH, for example decreasing thyroid output by half, and then running 12.5mcg t3 will further suppress the thyroid to zero output, but i assume it does and so i think for a person whose thyroid is being suppressed by drugs should probably just run replacement dosage or none at all.
also, t3 needs to be taken on an empty stomach in the morning, as it gets absorbed in the stomach and certain minerals will interfere with it's absorption, more so when you take research company levothyroxine (which is what they all buy from china). MP is legit and the only RC i'd use, but i get my t3 from ADC now, i prefer it since it's pharm grade, B+ pharmaceutical quality but still a step-up from RC.