Monkeys Got Shredded On Peptides?!!

Weight loss is not the same thing as fat loss. A 2025 monkey study combining semaglutide with experimental myostatin and activin A antibodies raised the possibility of protecting lean mass while losing fat. Now COURAGE phase 2 data provide a human lean-mass preservation signal — alongside serious safety and tolerability concerns with the triple combination. John Garrett, RN, separates animal results, company-reported human data, body-composition measurements, and clinical outcomes. Trevogrumab and garetosmab are investigational monoclonal antibodies, not approved muscle-preserving peptides. Educational content only. Research links: https://doi.org/10.1038/s41467-025-59485-9 ; https://clinicaltrials.gov/study/NCT06299098 ; https://newsroom.regeneron.com/news-releases/news-release-details/phase-2-courage-trial-confirms-trevogrumab-prevents-lean-mass