Weight-loss drug found to shrink muscle in mice, human cells

There are a lot of people here citing loss of muscle mass as a side effect of GLP-1s, when the reality is that weight loss almost always comes with muscle loss.

For me, that hasn't even been the case. I'm down 40lbs on a relatively low dose of Semaglutide and my muscle mass has moderately increased over the last 6 months. The hysteria over this is totally unfounded.

Yep. I started resistance training 5x a week about a month in on tirzepatide and even with a severely restricted caloric intake (I just can't eat enough), I've gained LBM.

How did you measure the increase in LBM? This requires very advanced technical equipment. My suspicion is that you have noticed an increase in muscle volume and assumed it to be an increase in muscle mass. Those are largely due to water retention and increased blood flow. They revert quite quickly after you stop exercising for about a week.

Does ability to lift weight also decrease in about a week? I was recently out of town for over two weeks and came back with the ability to lift roughly the same amount I was able to prior to leaving.

My DEXA scans seem roughly correlated with the amount of weight I can do in my regular sets, which has increased about 50-70% depending on which muscle group you are talking about.

This is with heavy resistance training 3 times a week and Pilates once a week.

A good portion of the strength related to any specific lift is CNS adaptation up until a certain point (and most new lifters won't hit that threshold for quite some time), so strength on a lift you've been doing regularly isn't necessarily a good indicator. Building muscle will of course increase your strength too, but I've doubled my squat since getting back into lifting while certainly not doubling the muscle mass of the respective muscles.