GLP-1 weight loss drugs like Ozempic and Wegovy are making headlines, but are they stripping away muscle and fat? That question was recently posed to Dr. Layne Norton, PhD in Nutritional Sciences. While there’s some truth to the concern, Dr. Norton pointed out that these medications remain the most effective weight loss treatment available.
With GLP-1 mimetics we have, on average, people lose about 15-20% of their body weight and keep it off.
—Dr. Layne Norton
Yes, Dr. Norton says these drugs can lead to a reduction in lean muscle mass, but the same can happen with diet and exercise. Fat loss isn’t localized, and any weight loss method typically involves some degree of muscle loss. The key is minimizing this muscle reduction through quality nutrition and strength training.
[Related: Fat Burn Isn’t Fat Loss. Here’s Why]
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How GLP-1 Medications Work; Influence on Lean Mass
GLP-1 drugs mimic a hormone (glucagon-like peptide-1) that regulates blood sugar and suppresses appetite, making them powerful tools for weight loss. They were originally developed for type 2 diabetes. They can help users shed a significant percentage of their body weight, an option that, for some, is more appealing than traditional dieting and exercise.
They are simply the most powerful appetite suppressants we have ever encountered.
—Dr. Layne Norton
While these medications can be life-changing for weight loss, not all lost weight is pure fat. DEXA scans show that lean mass is measured as a whole, which includes muscle, water, food in the gut, organs, bones, and even some fat tissue (about 13% of fat is lean).
Key Takeaways
GLP-1 meds don’t magically burn belly fat, and they don’t boost metabolism. They simply curb hunger, making adhering to a calorie deficit easier. (1) While muscle loss is part of any weight loss journey, resistance training, and protein intake can help minimize it.
Ultimately, these drugs are a tool, not a shortcut. Long-term success still requires healthy nutrition, strength training, and consistency with both.
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Reference
- Moiz A, Filion KB, Tsoukas MA, Yu OH, Peters TM, Eisenberg MJ. Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation. Am J Med. 2025 Jan 31:S0002-9343(25)00059-2. doi: 10.1016/j.amjmed.2025.01.021. Epub ahead of print. PMID: 39892489. https://pubmed.ncbi.nlm.nih.gov/39892489/
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