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GLP-1 muscle loss by the numbers

The key statistics on muscle loss with GLP-1 medications, each cited to published research and free to reference. If you write about this, link the number and it links back to its source.

Updated July 14, 2026 Every figure cited
15–40% of the weight lost on a GLP-1 is lean mass, not fat, across reviews of the trial data.1
~26% of tirzepatide weight loss was lean mass in the SURMOUNT-1 DXA body-composition data.1
1.6–2.2 grams of protein per kg of body weight per day is the range that protects lean mass during weight loss, roughly double the 0.8 g/kg RDA.2
1.2–1.6 grams per kg per day is the more conservative protein range in a GLP-1-specific nutrition advisory from four medical societies.3
~93.5% of the lean mass that caloric restriction alone would cost was offset by resistance training in a meta-analysis of older adults.4
~43% of GLP-1 users met even a modest daily protein minimum in a cross-sectional study, a sign of how hard intake is on a suppressed appetite.5
~25% reduction in overall energy intake on semaglutide in controlled data, which is why protein is the first thing to fall.6
0.4 g/kg of protein per meal, across roughly four meals, is the distribution that best supports muscle protein synthesis.7

What the numbers add up to

Read together, these figures tell one story. A large share of GLP-1 weight loss is muscle rather than fat, the medication makes hitting a protective protein target harder by cutting intake, and the two levers that reverse it are a higher protein target from complete sources and resistance training. None of these numbers is a verdict on any individual; they are population findings, and body composition, kidney health, and clinician judgment all shape what is right for a given person.

Want the number scaled to your own weight? The free calculator applies the protein range and projects muscle retention with versus without training. For the full protocol behind these figures, the protein guide and the exercise guide walk through the how.

Go deeper

Preserving Lean Mass on GLP-1 Therapy

The complete, fully-cited handbook turns these numbers into a protocol: the protein system, two gym routines plus a bodyweight-only program, side-effect and maintenance strategy.

See the handbook — $5 →

References

  1. Neeland IJ, et al. Changes in lean body mass with established and emerging GLP-1-based therapies and mitigation strategies. Diabetes, Obesity & Metabolism. 2024. doi.org/10.1111/dom.15728
  2. Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance-training-induced gains. British Journal of Sports Medicine. 2018. pmc.ncbi.nlm.nih.gov/articles/PMC5867436
  3. Mozaffarian D, Agarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory. 2025. pmc.ncbi.nlm.nih.gov/articles/PMC12304835
  4. Sardeli AV, et al. Resistance training prevents muscle loss induced by caloric restriction in obese elderly: a systematic review and meta-analysis. Nutrients. 2018;10(4):423. mdpi.com/2072-6643/10/4/423
  5. Investigating nutrient intake during use of GLP-1 receptor agonist: a cross-sectional study. Frontiers in Nutrition. 2025. frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1566498/full
  6. Wharton S, et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg (STEP 1–3 pooled analysis). Diabetes, Obesity & Metabolism. 2022. pmc.ncbi.nlm.nih.gov/articles/PMC9293236
  7. Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Journal of the International Society of Sports Nutrition. 2018. pmc.ncbi.nlm.nih.gov/articles/PMC5828430

Citing these figures? A link to this page or the underlying study is appreciated. This page is educational and not medical advice.