# How to keep muscle while losing weight on Ozempic or Mounjaro

Roughly 25 to 40% of the weight you lose on a GLP-1 like Ozempic or Mounjaro is lean mass, not fat, but two habits protect your strength: lift weights two to three times a week and eat about 1.2 to 1.5 g of protein per kg per day. The numbers are less alarming than the headlines, because DXA "lean mass" also counts water, glycogen and organ tissue, and in trials body composition and even grip strength often improved. What matters is tracking strength and function, not just the scale.

A big slice of GLP-1 weight loss is lean mass, not just fat. Good news: two simple habits protect your strength, and the trial numbers are far less scary than the headlines.

## On this page

- How much muscle do you actually lose on Ozempic or Mounjaro?
- Is losing muscle on a GLP-1 actually a problem?
- What kind of exercise keeps muscle while losing weight?
- How much protein should you eat on a GLP-1, and why is it so hard?
- How do you track whether you are keeping muscle, not just losing weight?
- Are there muscle-sparing weight-loss drugs yet, and what do they cost in Germany?

## FAQ

- How much of the weight you lose on Ozempic is muscle?
- Will I get sarcopenia from taking a GLP-1?
- Do I need to lift weights on Mounjaro or Wegovy?
- How much protein should I eat while on a GLP-1?
- Is there a weight-loss drug that doesn't cause muscle loss?
- Does losing muscle on semaglutide make me weaker?
- How can I check if I'm losing muscle instead of fat?

## Sources

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- Look M, Dunn JP, Kushner RF, Cao D, Harris C, Hunter Gibble T, Stefanski A, Griffin R. (2025). Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes, Obesity and Metabolism. https://doi.org/10.1111/dom.16275
- Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, Kiyosue A, Zhang S, Liu B, Bunck MC, Stefanski A; SURMOUNT-1 Investigators. (2022). Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine. https://doi.org/10.1056/NEJMoa2206038
- Binmahfoz A, Dighriri A, Gray C, Gray SR. (2025). Effect of resistance exercise on body composition, muscle strength and cardiometabolic health during dietary weight loss in people living with overweight or obesity: a systematic review and meta-analysis. BMJ Open Sport & Exercise Medicine. https://doi.org/10.1136/bmjsem-2024-002363
- Bauer J, Biolo G, Cederholm T, Cesari M, Cruz-Jentoft AJ, Morley JE, Phillips S, Sieber C, Stehle P, Teta D, Visvanathan R, Volpi E, Boirie Y. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association (JAMDA). https://doi.org/10.1016/j.jamda.2013.05.021
- Deutz NEP, Bauer JM, Barazzoni R, Biolo G, Boirie Y, Bosy-Westphal A, Cederholm T, Cruz-Jentoft A, Krznaric Z, Nair KS, Singer P, Teta D, Tipton K, Calder PC. (2014). Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Clinical Nutrition. https://doi.org/10.1016/j.clnu.2014.04.007
- Heymsfield SB, Aronne LJ, et al.. (2026). Bimagrumab plus semaglutide alone or in combination for the treatment of obesity: a randomized phase 2 trial (BELIEVE). Nature Medicine. https://doi.org/10.1038/s41591-026-04204-0
- Alissou M, Demangeat T, Folope V, et al.. (2025). Impact of Semaglutide on fat mass, lean mass and muscle function in patients with obesity: The SEMALEAN study. Diabetes, Obesity and Metabolism. https://doi.org/10.1111/dom.70141
- Prokopidis K, et al.. (2026). Glucagon-like peptide-1 receptor agonists and muscle strength changes in older adults: Risks beyond muscle mass reductions. British Journal of Pharmacology. https://doi.org/10.1111/bph.70355
- Sardeli AV, Komatsu TR, Mori MA, Gáspari AF, Chacon-Mikahil MPT. (2018). Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis. Nutrients. https://doi.org/10.3390/nu10040423
- Mechanick JI, Butsch WS, Christensen SM, et al.. (2025). Strategies for minimizing muscle loss during use of incretin-mimetic drugs for treatment of obesity. Obesity Reviews. https://doi.org/10.1111/obr.13841
- Tinsley GM, Nadolsky S. (2025). Preservation of lean soft tissue during weight loss induced by GLP-1 and GLP-1/GIP receptor agonists: A case series. SAGE Open Medical Case Reports. https://doi.org/10.1177/2050313X251388724
- Villareal DT, Aguirre L, Gurney AB, et al.. (2017). Aerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa1616338
- Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. (2012). Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition. https://doi.org/10.3945/ajcn.112.044321
- Prado CM, Phillips SM, Gonzalez MC, Heymsfield SB. (2024). Muscle matters: the effects of medically induced weight loss on skeletal muscle. The Lancet Diabetes & Endocrinology. https://doi.org/10.1016/S2213-8587(24)00272-9

_Full guide: https://longevity-switzerland.com/en/guide/glp1-muskelerhalt_

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_Canonical: https://longevity-switzerland.com/en/guide/glp1-muskelerhalt · Part of Longevity Cities · Updated 2026-06-22_