GLP-1 medications, also known as GLP-1 receptor agonists (like Ozempic, Wegovy, or Mounjaro) have become popular tools to support weight loss and help manage Type 2 Diabetes and other Metabolic conditions.

These medications work by reducing appetite, slowing digestion, and helping people feel fuller for longer. While they can be very effective for weight management, one important thing to be aware of is how they can affect your muscle mass.

How GLP-1s Affect Muscle Mass

Studies have shown that whilst the use of GLP1s does result in overall weight loss, some of that loss comes from our muscles, not just fat. This is especially the case when we lose weight quickly, over a short period of time which is often the case when using GLP1s.

Additionally, due to appetite suppression, GLP-1 medications can lead to reduced calorie intake, which may increase the risk of losing lean muscle tissue as we no longer consume as much protein to maintain muscle.

Why Muscle Loss Is a Concern

Muscle plays a key role in keeping our metabolism healthy, supporting joint function, and allowing us to move and complete tasks of daily living with ease. Significant or ongoing loss of muscle mass and strength is known as sarcopenia, a condition which often happens as we age and is exacerbated by chronic health conditions including Diabetes, Chronic Kidney Disease and Cardiovascular disease. Sarcopenia can lead to fatigue, weakness, frailty, poor balance and a higher risk of injuries or falls, reducing overall independence and quality of life.

Because GLP-1 medications can suppress appetite and lead to rapid weight and muscle loss, they may exacerbate the risk of sarcopenia, especially if exercise and adequate protein intake aren’t maintained.

Additionally, this muscle loss can also contribute to reduced bone density, increasing the risk of osteoporosis and fractures, particularly in older adults. Protecting muscle through the right exercise and nutrition strategies is therefore vital when using GLP-1 medications.

How Exercise Protects Your Muscle

The good news? Exercise, especially resistance training, is one of the most powerful tools to protect and build muscle while using GLP-1 medications. Completing weight bearing exercise using dumbbells, machines, resistance bands and your own body weight can help to maintain muscle mass, even during weight loss.

Regular resistance training also improves overall strength, bone density, body composition, and overall fitness. Resistance training needs to be completed regularly and progressively to ensure the benefits of muscle mass maintenance are achieved.

Why Work With an Exercise Physiologist

Everyone’s body responds differently to weight loss and exercise. An Accredited Exercise Physiologist (AEP) can design a safe, individualised program that fits your current fitness level, exercise history, medication use, and goals.

Your Exercise Physiologist will help you build strength, maintain muscle mass, and safely progress your exercise routine while ensuring your training complements the effects of your GLP-1 medication and taking into account any other health considerations.

Don’t Forget About Nutrition

Exercise and nutrition go hand in hand. Getting enough protein is especially important to help your muscles recover and grow when undergoing resistance training. Because GLP-1s can reduce appetite, it’s easy to under-eat protein without realising it.

Working with an Accredited Practising Dietitian alongside your Exercise Physiologist, ensures you’re getting the right balance of nutrients to support muscle health and overall wellbeing, whilst also providing you with tips on how to prioritise protein intake with a reduced appetite.

In Summary

GLP-1 medications can be an effective part of a weight management plan, but protecting your muscle mass is essential for long-term health. Combining regular resistance training with the guidance of an Accredited Exercise Physiologist and a balanced, protein-rich diet supported by a Dietitian is the best way to stay strong, functional, and healthy while on your GLP-1 journey.

References:
Linge, J., Birkenfeld, A.L. and Neeland, I.J., 2024. Muscle mass and glucagon-like peptide-1 receptor agonists: adaptive or maladaptive response to weight loss?. Circulation, 150(16), pp.1288-1298.
Memel, Z., Gold, S.L., Pearlman, M. et al. Impact of GLP- 1 Receptor Agonist Therapy in Patients High Risk for Sarcopenia. Curr Nutr Rep 14, 63 (2025). https://doi.org/10.1007/s13668-025-00649-w

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