Rapamycin induced insulin resistance and drop in testosterone

The study that I linked is very favorable towards rapamycin effects in mice re insulin. Short term usage is bad but longer-term usage turns favorable.


The day after I read this I got my labs for a PE. Been on on Rapa about three months (2.5mg MWF initially , then 7.5mg once weekly more recently. Lo and behold, both Total and Free T 2/3 lower than six months ago. I have been on HRT for a several years (72yo, male) and have had levels consistently in high normal range for the lab).
My skeletal muscle mass has also declined. I train cardio and strength regularly. My trainer has noted that since taking rapa, I have plateaued in my lifting where I had been hitting PR’s on a fairly regular basis.
Going off rapa, and will retest in three months to rule out that variable (the other variable being the compounding pharmacy that makes up the cream for topical application; cannot do injections as on anti-coaguant).

PS My doc was blown away by significant improvement in my lipids. WBC/neutrophils down a bit.


Thank you for sharing this important info dogdoc!

Please let us know if your testosterone levels return to your normal baseline after going off rapamycin for 3 months. Hopefully the apparent detrimental effect of rapamycin on testosterone levels is reversible.

That’s just weird because if you are on Trt your endogenous testosterone production stops which means that if you didn’t change your Trt dosing schedule your testosterone gets used up or broken down quicker…

Testosterone levels drop quickly at the end of the weekly dosing interval. So, day of testing relative to the date of administration can make a big difference.