ive been taking metformin for around two decades to treat prediabetes. I have experienced none of the side effects discussed above. Im taking extended release.
Until I hurt my knee running up some stairs about 2 years ago, my working weight on squats was at 350 (5 x10's) So, no noticeable impact on exercise. I am able to get strong and maintain strength. Im 47.
When I first started taking it there was a rocky period that lasted about 2 weeks, after that no intestinal issues at all.
Metformin did not help me lose weight, but I believe that it has helped me keep weight off. For me this is huge, at one point I weighed well over 141 kg. My blood glucose on metformin seems to be locked at about 85.
Every time I go into my doctors, they always seem excited to tell me that there are prospects that I could get off of metformin. They don't get it, I never want to get off metformin. It has been a miracle for me.
as for rapamycin
If I knew how to get my hands on some quality rapamycin, I would take it as well. My doctor wont prescribe it for off label use though, and I don't know any other way.
they both appear to be pretty amazing molecules