Does retatrutide cause muscle loss?
Some lean mass is lost along with fat, but in the one body-composition analysis the share of weight lost as lean mass was similar to other obesity treatments.
Short answer
Some lean mass is lost along with fat, but in the one body-composition analysis the share of weight lost as lean mass was similar to other obesity treatments.[1]
The authors wrote that the result could reassure that retatrutide does not take a greater proportion of lean mass despite producing larger overall weight loss.[1]
What limits that answer
The data come from a diabetes-only substudy of an earlier trial, and only 103 participants had both a baseline and a week 36 body scan.[1]
The company that makes the drug paid for that substudy.[1]
A review of incretin-type weight-loss drugs, retatrutide among them, says the class causes rapid lean-mass loss of roughly 10% or 6 kg; this is a class-level figure, not a retatrutide measurement.[2]
A dermatology review cites early trial data as showing a body-composition profile that favours fat over lean mass loss.[3]
More questions on Retatrutide
More on Retatrutide
Sources
- 1Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial.The lancet. Diabetes & endocrinology · 2025PMID 40609566Accessed 2 Oct 2026
- 2Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition?Diabetes care · 2024PMID 38687506Accessed 2 Oct 2026
- 3Integrating glucagon-like peptide-1 receptor agonists into dermatology practice: Safety and monitoring strategies.Clinics in dermatology · 2026PMID 42562129Accessed 29 Oct 2026
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