GLP-1 Medications and Athletes: What You Need to Know About Muscle and Performance

Written by: Mara Vazquez

Revised by: Rocío Rivera-Ortega, MS, RD, LND & Tatiana Velez, MS, RD, CSSD, LND

GLP-1 drugs remain a major topic across all wellness social media. For many type 2 diabetes patients, GLP-1 medications have been life-changing. In recent years, however, these medications have gained a lot of attention for another reason: their ability to reduce appetite and support weight loss. GLP-1 medications have revolutionized weight loss by mimicking the effects of a natural hormone called glucagon-like peptide-1 (GLP-1), which helps regulate appetite and feelings of fullness. By making people feel fuller and less hungry, these medications can make it easier to eat less and lose weight. But losing weight is not only about the number on the scale. Weight loss can include both fat and lean mass, which is everything in the body that is not fat, including muscle. This is especially important for athletes, since muscle helps support strength, movement, and performance. (1)

So what does weight loss mean for athletes?

For most people using GLP-1 medications, losing weight may be the main goal. For athletes, it is a little more complex than just weight loss. Athletes need enough energy and nutrients to train, recover, maintain muscle, and perform. When appetite is reduced, it may become harder to meet these needs. This is especially true for athletes with high energy and training demands, in which if these needs aren't met, their performance can be negatively impacted.

Weight loss can come from both fat and lean mass, and one of the major concerns with weight loss from GLP-1 medications is the reduction in lean mass. Approximately 25% of the weight loss from these medications was attributed to lean body mass. However, even though lean mass doesn’t represent just muscle; it includes water, organs, and tissues in the body, it is often used as an estimate of muscle mass. Therefore, maintaining lean mass during weight loss is important because muscles and internal organs use more energy at rest than the same amount of fat, so preserving lean mass can support your metabolism and make it easier to manage weight loss over time. Exercise can also help protect lean mass during weight loss. In particular, resistance training, such as lifting weights or using resistance bands, can help reduce the amount of lean mass lost during weight loss. (2,3,4)

For athletes, the goal should never be to just reach a lower body weight. Body dissatisfaction, the belief that a lower body weight will improve performance, and social pressure to look a certain way can all influence athletes to change their dietary behaviors and pursue weight loss. This pressure can come from coaches, teammates, and social media, particularly in sports where body weight or leanness is emphasized. These behaviors can increase the risk of low energy availability, which occurs when the body does not have enough energy left to support all of its physiological functions, potentially affecting both health and performance. Focusing on maintaining and/or building muscle while lowering fat, when appropriate, with adequate nutrition can help support strength, recovery, and performance. (5)

how Can Athletes Maintain Muscle?

Nutrition and exercise go hand in hand when trying to maintain muscle, especially during weight loss. For most active individuals, consuming around 1.2- 2.0 g of protein per kg of body weight per day is recommended to support muscle maintenance and recovery, but individual needs can vary depending on training, sport, and calorie intake. (6) Especially, for athletes needs may be higher.

Because one side effect of GLP-1 is reduced appetite, athletes might find it harder to meet their energy needs throughout the day. Therefore, making sure to reach an adequate calorie intake that meets total energy needs is important to support muscle maintenance. Planning regular meals and snacks and monitoring overall macro intake, such as consuming enough protein, carbohydrates, and fats, can help athletes meet their nutritional needs, even when appetite is reduced. (7)

Resistance training is also essential for maintaining muscle during weight loss. Strength exercises provide a stimulus that helps maintain and increase muscle mass, especially when combined with adequate protein and energy intake. (8)

Can GLP-1 Medications Affect Athletic Performance?

Although research on the direct effects of GLP-1 medications on athletic performance is still limited, since most studies have focused on people with type 2 diabetes or obesity, the medication can indirectly influence an athlete's ability to train and recover. Side effects, which include nausea and vomiting, diarrhea, constipation, and a significant reduction in appetite, can make it harder to eat enough, stay hydrated, and show up to training feeling ready to perform.

These side effects can be more noticeable during the first weeks after starting the medication or increasing the dose. Lower calorie intake combined with GI discomfort can negatively affect performance, making training sessions feel harder than usual. These medications can also reduce the perception of thirst. When combined with side effects such as vomiting or diarrhea, this can increase the risk of dehydration, which is an important concern for athletes. (9)

GLP- 1 Medications and Athletes: What Should You Consider?

If you’re an athlete considering or currently taking one of these medications, working with a sports dietitian can help you meet your nutritional needs while focusing on maintaining muscle mass and supporting your performance. Including protein at every meal, along with strength training two to three times a week, can help maintain muscle and minimize muscle loss. Staying hydrated is also important, since these medications may reduce thirst as well as hunger. If you experience side effects such as vomiting or diarrhea, replacing fluids and electrolytes can be especially important to help prevent dehydration. Most importantly, pay attention to how you’re feeling, performing, and recovering rather than focusing only on the number on the scale. These can give you a better idea of how your body is responding to the medication and help you recognize any side effects that may be affecting your performance.

Are GLP-1 Medications allowed in Sports?

Competitive athletes should always be aware of anti-doping regulations. Although GLP-1s are currently permitted in sport, it is important for athletes to know that the World Anti-Doping Agency, or WADA, is monitoring the use of GLP-1’s by athletes to determine if they should be prohibited in the future and is currently in its Monitoring Program. Therefore, athletes should always verify the most current WADA Prohibited List and consult their team’s medical staff or anti-doping organization before starting any medication. (10)

Conclusion

GLP-1 medications can be very helpful for managing certain health conditions and support weight loss, but for athletes, there is much more to consider. Maintaining adequate energy and protein intake, continuing resistance training, staying hydrated, and paying attention to recovery can help support muscle and performance while on these medications. Since every athlete has different nutrition and training needs, working with a healthcare professional and sports dietitian can help create an individualized, tailored plan that supports both health and athletic performance.

References

Reiss, A. B., Gulkarov, S., Lau, R., Klek, S. P., Srivastava, A., Renna, H. A., & De Leon, J. (2025). Weight reduction with GLP-1 agonists and paths for discontinuation while maintaining weight loss. Biomolecules, 15(3), Article 408. https://doi.org/10.3390/biom15030408
Karakasis, P., Patoulias, D., Fragakis, N., & Mantzoros, C. S. (2025). Effect of glucagon-like peptide-1 receptor agonists and co-agonists on body composition: Systematic review and network meta-analysis. Metabolism, 164, Article 156113. https://doi.org/10.1016/j.metabol.2024.156113
Codella, R., Senesi, P., & Luzi, L. (2025). GLP-1 agonists and exercise: The future of lifestyle prioritization. Frontiers in Clinical Diabetes and Healthcare, 6, Article 1720794. https://doi.org/10.3389/fcdhc.2025.1720794
Neeland, I. J., Linge, J., & Birkenfeld, A. L. (2024). Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. https://doi.org/10.3390/biom15030408Diabetes, Obesity and Metabolism, 26(Suppl. 4), 16–27. https://doi.org/10.1111/dom.15728
Wasserfurth, P., Palmowski, J., Hahn, A., & Krüger, K. (2020). Reasons for and consequences of low energy availability in female and male athletes: Social environment, adaptations, and prevention. Sports Medicine - Open, 6, Article 44. https://pmc.ncbi.nlm.nih.gov/articles/PMC7483688/
Egan, B. (2016). Protein intake for athletes and active adults: Current concepts and controversies. Nutrition Bulletin, 41(3), 202–213. https://doi.org/10.1111/nbu.12215
Mozaffarian, D., Agarwal, M., Aggarwal, M., Alexander, L., Apovian, C. M., Bindlish, S., Bonnet, J., Butsch, W. S., Christensen, S., Gianos, E., Gulati, M., Gupta, A., Horn, D., Kane, R. M., Saluja, J., Sannidhi, D., Stanford, F. C., & Callahan, E. A. (2025). Nutritional priorities to support GLP-1 therapy for obesity: A joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and the Obesity Society. Obesity Pillars, 15, Article 100181. https://doi.org/10.1016/j.obpill.2025.100181
Cava, E., Yeat, N. C., & Mittendorfer, B. (2017). Preserving healthy muscle during weight loss. Advances in Nutrition, 8(3), 511–519. https://doi.org/10.3945/an.116.014506
Kim, J. A., & Yoo, H.-J. (2025). Exploring the side effects of GLP-1 receptor agonist: To ensure its optimal positioning. Diabetes & Metabolism Journal, 49(4), 525–541. https://doi.org/10.4093/dmj.2025.0242
U.S. Anti-Doping Agency. (2026, April 15). Weight loss drugs: What athletes need to know about GLP-1s. https://www.usada.org/spirit-of-sport/weight-loss-drugs-glp-1s/