Oh, I see potential utility of Metformin for “chemically assisted” lifters, maybe, I just don’t buy into the hype that you see on a lot of longevity forums and groups recommending everyone and their mother use Metformin, saying that it’s the best thing there is for longevity and anti-aging for everyone. For your normal natty gym rat, or even your normal person who exercises regularly but not terribly intensely, I still don’t think I’d recommend Metformin. Berberine though does seem to have utility for these normal people, as Shawn said, and the research seems to suggest too.
Edit: but please also note that Metformin blunted more beneficial adaptations to exercise than simply muscle growth, so I’m not sure how the addition of anabolics would impact these other parameters when paired with exercise. Things like cardiorespiratory fitness and insulin sensitivity; Metformin blunted the positive effects exercise had on these things too.