The effect of rapamycin on muscle growth and strength

Although it’s well known that mTORC1 activation stimulates protein synthesis and is necessary for muscle growth, too much mTORC1 for too long may have opposite effects.

The study below shows that mutant mice with chronically activated mTORC1 have skeletal muscle atrophy and reduced muscle strength. Administration of rapamycin to such mutant mice in old age results in increased autophagy and partial reversal of the skeletal muscle atrophy and strength, as seen in the following study:

Older animals may also suffer from chronically elevated mTORC1 similar to the mutant mice, although to a smaller extent. When atrophy due to muscle disuse is induced in old rats, they were found to have limited recovery of muscle mass in response to reuse, despite having higher myofibrillar protein synthesis than young adult rats. They also had higher rates of protein degradation. The authors speculated that the higher rate of protein synthesis in the older rats contributed to increased rates of protein misfolding and aggregation and that this was a result of chronically elevated mTORC1. See the study below:

I think this may be one of the reasons why rapamycin use does not appear to make it harder for people to gain or maintain muscle mass even in those taking pretty high doses.


This is interesting… genetic predisposition for strength. Counties for long-lived populations.


Of course you like this Olafur Pall Olafsson, it’s about your people. Iceland, Sweden, Finland. Hahaha.


Apparently I have those strength genes turned on - upside
I also have 12 of the key 13 fat genes turned on - downside

Interestingly genetic predispositions are just that and don’t always manifest but if you don’t know, then you might not be doing the things that can “defeat” or support a genetic predisposition.

For me, GLP-1R + GIP fixes the fat gene thing :slight_smile:

So I think that the GLP1 family of drugs are very potent longevity drugs. There are some interesting studies going on regarding the other benefits thse drugs provide beside glucose control.


Yes there are definitely some strength genes running in my family line. My younger brother competed in the strongest man in the world in the under 90 kg category last year. Those vikinig genes :wink: