A new study presented at the Endocrine Society’s ENDO 2025 conference suggests that these groups are more vulnerable to muscle mass loss while using semaglutide. While this doesn’t have to be catastrophic, it does have consequences. Researchers suspect that extra dietary protein may help slow this effect.
Muscle loss — also called loss of lean mass — is common in people with obesity who lose weight. According to Dr. Melanie Haines of Massachusetts General Hospital and Harvard Medical School, this can affect metabolism and bone health. Muscles play an active role in regulating blood sugar and contribute to structural stability.
Semaglutide, a GLP-1 receptor agonist, is increasingly used for overweight and obesity. However, earlier research shows that approximately 40% of weight loss from this medication comes from muscle tissue and other lean mass. It’s still unclear who is most susceptible to this and how strongly it affects blood sugar control.
To gain more insight, researchers followed forty people with obesity over three months. Twenty-three of them received semaglutide. The remaining seventeen participated in a lifestyle program with nutrition and exercise — Healthy Habits for Life (HHL). Muscle mass was measured in both groups throughout the study.
Muscle Loss in Both Groups, But Protein and Age Make a Difference
Participants taking semaglutide lost more weight on average than the group that only focused on lifestyle changes. However, the proportion of muscle mass in the weight loss was comparable between the two groups.
Yet researchers noticed something striking: within the semaglutide group, women, older adults, and people with low protein intake experienced relatively more muscle loss. And those who lost more muscle mass made less progress in blood sugar levels (HbA1c).
“Women and older adults appear more sensitive to muscle loss when using semaglutide. However, higher protein intake during weight loss may offer protection,” Haines said. “Excessive muscle loss can negate the positive effects on blood sugar. That’s why muscle preservation is essential — not just for strength, but also for metabolic health.”
According to Haines, more research is needed to determine how to combine fat loss with semaglutide while preserving muscle mass. High-protein nutrition and strength training may play a key role in this.
Conclusion
A recent study shows that older adults and women taking semaglutide may lose more muscle mass, which can limit the medication’s effect on blood sugar levels. Higher protein intake appears to partially offset this risk.
Verified Sources
- Consuming more protein may protect patients taking anti-obesity drug from muscle loss
- With thanks to SciTechDaily
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Frequently Asked Questions
What exactly does semaglutide do in the body?
Semaglutide is a GLP-1 receptor agonist. It slows stomach emptying, reduces appetite, and helps with weight loss. It’s often prescribed for overweight, obesity, and type 2 diabetes.
Why is muscle preservation so important when losing weight?
Muscles support blood sugar regulation and contribute to strength, mobility, and bone health. Those who lose too much muscle mass during weight loss risk weakness, slowed metabolism, and insulin resistance.
How much protein should you eat if you’re taking semaglutide?
This varies by person, but a guideline for people with overweight is between 1.2 and 1.6 grams of protein per kilogram of body weight per day — especially if strength training is involved. Consult a dietitian for a personalized plan.
Is strength training recommended while taking semaglutide?
Yes. Strength training helps preserve or even build muscle mass during weight loss. It can compensate for the negative effects of semaglutide on muscle mass.
Can you completely prevent muscle loss when taking semaglutide?
Complete prevention is difficult, but with adequate protein, regular strength training, and a gradual approach, it’s possible to significantly limit muscle loss.
