Welcome to issue one. Quick deal before we start: I read the studies, I grade every claim by how strong the evidence actually is, and I tell you what I'm doing with my own body. You make your own calls with your own doctor. That's the whole newsletter.
This week: the "GLP-1s melt your muscle" panic, examined properly.
🔴 BOSS FIGHT: Does weight-loss-in-a-pen cost you your muscle?
If you lift, you've heard it. Somebody at the gym says Ozempic guys lose half their weight as muscle. Scary line. Mostly wrong, partly worth taking seriously. Here's what the data actually says.
The new head-to-head. A comparison of the two big players found that people on tirzepatide (Mounjaro/Zepbound) lost about 1.1% more lean body mass than semaglutide (Ozempic/Wegovy) users at 3 months, widening to about 2% by 12 months. 🟡 MODERATE. Before you crown a winner, note the likely reason: tirzepatide simply causes more total weight loss. Lose more weight, lose more of everything.
The pushback on the panic. A March 2026 paper in Cell Reports Medicine looked at muscle specifically and found GLP-1 weight loss did not cause disproportionate muscle loss in either mice or humans. 🟡 MODERATE. "Disproportionate" is the key word. You lose some lean mass with ANY major weight loss, drug or no drug. The question was never whether you lose lean mass, it's whether these drugs make it worse than dieting the old way. So far the answer looks like no.
What "lean mass" hides. One thing the headlines skip: lean mass on a DEXA scan isn't just muscle. It includes water and organ tissue, and rapid weight loss shifts those too. A drop in "lean mass" does not automatically mean your quads vanished. 🟢 STRONG on the measurement point, it's just how body composition works.
What actually protects muscle. The boring answer that survives every study: resistance training and adequate protein while losing weight. 🟢 STRONG. That was true before these drugs existed and the early GLP-1 plus lifting data says it's still true.
My read: for a guy over 40 considering a GLP-1, muscle loss isn't a reason to avoid them. Going on one WITHOUT a lifting program and a protein target is the actual mistake. The drug empties the tank; what you keep depends on what you're doing while it happens.
Not medical advice. Whether any of this fits your situation is a conversation for you and your doctor.
📋 PATCH NOTES
FDA might unlock the peptide vault. An FDA advisory committee meets July 23-24 to consider returning seven restricted peptides (including BPC-157 and TB-500) to legal compounding status. If that happens, the gray market gets a lot less gray. Mark the date. ⚪ REGULATORY
TRT safety, the honest version. The 5,200-man TRAVERSE trial cleared testosterone therapy of heart attack and stroke risk, but found real signals on atrial fibrillation and pulmonary embolism. Anyone telling you TRT is risk-free hasn't read the trial. 🟢 STRONG
Creatine might be brain fuel too. A 2026 systematic review found early signal that creatine helps cognition in healthy older adults. Catch: your brain holds about 5% of body creatine, so brain effects may need more than the gym-standard dose. Watch this space. 🟠 PRELIMINARY
Oral TRT is getting real. New-generation oral testosterone (Kyzatrex) restores levels in most men without the liver problems of the old pills. Changes the math for the needle-averse. 🟡 MODERATE
That "sleep crushes testosterone" stat is shakier than you think. The famous 10-15% drop from short sleep comes from a small study; a newer RCT found no significant effect. Sleep still matters for a dozen other reasons. The hormone story is just messier than the meme. 🟡 MODERATE
🎮 THE QUEST LOG
Since the deep dive is about GLP-1s and muscle, fair's fair: here's my own run.
I spent about three months on one of the newer triple-agonists in the GLP-1 family (not naming it, it's still investigational, and this isn't a recommendation). The weight came off, about 20 pounds. But I didn't feel good. The appetite suppression meant I just didn't want to eat, so my energy dropped, and my sleep got worse. I was still lifting heavy and still hitting my protein target, same as always. The training and the food didn't change. I just felt flat, and I looked smaller rather than leaner.
Then I ran tesamorelin, a synthetic growth hormone releasing hormone (a prescription peptide that signals your body to make more of its own growth hormone). Low dose, everything else identical. Same protein, same heavy lifting 3 to 4 times a week, same hour walk after. Completely different experience. My sleep was amazing. Energy was up. I was actually hungry, so I ate more, and most of it just burned off. The visceral fat dropped, I went from a size 32 to a size 28, the muscle stayed, and I saw a four-pack for the first time in years.
Same protein, same training, two very different results. For me the difference came down to how each one made me feel day to day: one shut my appetite and my sleep down, the other switched them on. If I had to choose again I'd skip the GLP entirely and go straight to tesamorelin. Lesson learned: GLPs just aren't for me.
My protocol, my body, my doctors. Not a template.
The 40+ Protocol is educational content, not medical advice. I'm a game designer reporting studies and my own n=1 experiments, not a doctor. Talk to yours before changing anything. No affiliate links in this issue.Then I ran tesamorelin, a synthetic growth hormone releasing hormone (a prescription peptide that signals your body to make more of its own growth hormone). Low dose, everything else identical. Same protein, same heavy lifting 3 to 4 times a week, same hour walk after. Completely different experience. My sleep was amazing. Energy was up. I was actually hungry, so I ate more, and most of it just burned off. The visceral fat dropped, I went from a size 32 to a size 28, the muscle stayed, and I saw a four-pack for the first time in years.