T3, risky business?

[Drake Hotel]

Can you elaborate on this "lower serum level" from 25mcg t3 ED? I was under the understanding that 25mcg t3 ED will slightly elevate your BMR and also aid in protein synthesis with a lot less chance of burning muscle. I understand that the body naturally produces around 25mcg of endogenous t3 but have also heard that a exogenous 25mcg t3 amount will be more effective at increasing BMR which will increase protein synthesis. Am I wrong? How effective would a 37.5mcg dose of t3 be?

I will try to elaborate, but it's difficult for me. Really the problem is that I don't know the correct half-life for the liothyronine salt (i.e. the drug, not what's endogenously produced). I have seen figures ranging from 1hr to 24hrs, so it all becomes difficult. But let's consider the endogenous production first. A healthy male produces about 37.5mcg T3 daily, i.e. 1.5 pill of Cytomel. Assuming that Cytomel has the same active-life as endogenously produced T3, you can see that taking only 25mcg or two thirds of what you produce yourself, will only 1) depress your own production, and 2) establish a lower serum level. If the active-life of Cytomel is longer than that of endogenous T3, then of course there might not be a problem with using only 25mcg daily.

I should add also that, at first, basically any dose of Cytomel will increase BMR, as it takes some time for endogenous production to be suppressed. I've used 25mcg before powerlifting meets and achieved effect; it kinda becomes 37.5+25mcg in that case. Not exactly of course, but you understand the principle.

Excuse me for this poorly written wall of text, but I think you can gain something from it at least. If not, simply ask more questions and I'll try to answer better I think it's interesting what you mention about Cytomel potentially having greater effect on BMR than an equal dose of endogenous T3. I've never heard of it before but it's certainly interesting.

Oh btw, on wikipedia it says that the half-life of Cytomel is 2.5 days!

[M302_Imola]

I will try to elaborate, but it's difficult for me. Really the problem is that I don't know the correct half-life for the liothyronine salt (i.e. the drug, not what's endogenously produced). I have seen figures ranging from 1hr to 24hrs, so it all becomes difficult. But let's consider the endogenous production first. A healthy male produces about 37.5mcg T3 daily, i.e. 1.5 pill of Cytomel. Assuming that Cytomel has the same active-life as endogenously produced T3, you can see that taking only 25mcg or two thirds of what you produce yourself, will only 1) depress your own production, and 2) establish a lower serum level. If the active-life of Cytomel is longer than that of endogenous T3, then of course there might not be a problem with using only 25mcg daily.

I should add also that, at first, basically any dose of Cytomel will increase BMR, as it takes some time for endogenous production to be suppressed. I've used 25mcg before powerlifting meets and achieved effect; it kinda becomes 37.5+25mcg in that case. Not exactly of course, but you understand the principle.

Excuse me for this poorly written wall of text, but I think you can gain something from it at least. If not, simply ask more questions and I'll try to answer better I think it's interesting what you mention about Cytomel potentially having greater effect on BMR than an equal dose of endogenous T3. I've never heard of it before but it's certainly interesting.

Oh btw, on wikipedia it says that the half-life of Cytomel is 2.5 days!

Thanks for the reply, I did shed some light from it. As far as 25mcg exogenous being greater than 25mcg endogenous (what the body naturally makes) is due to all the different coversions that t3 goes through (t4->t3 and vice versa) when made naturally (endogenously). I have heard that it looses some of its' potency due to these conversions. Plus the replace therapy dose of t3 I believe is 25mcg. I was under the impression that the half-life of t3 is somewhere between 8-12 hours.