Semaglutide: Weight Loss’s Hidden Cost on Muscle Mass

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New Study Suggests Higher Protein Intake May Mitigate Muscle Loss on Semaglutide for Women and Older Adults

Women and older adults taking the popular anti-obesity drug semaglutide may face a higher risk of muscle loss, but a new study suggests that boosting protein intake coudl help prevent this. The findings were presented at ENDO 2025, the Endocrine Society’s annual meeting in San Francisco, California.

Muscle, or lean mass, plays a crucial role in metabolism and bone health. It also helps control blood sugar after meals. Losing muscle during weight loss can negatively impact these functions.

Semaglutide, a type of drug known as a GLP-1 agonist, is well-known for its effectiveness in weight loss. However, approximately 40% of the weight lost on these medications can be lean mass, including muscle. The exact individuals most at risk for this loss and its impact on blood sugar levels are still being investigated.

Researchers conducted a three-month study involving 40 adults with obesity. Twenty-three participants were prescribed semaglutide, while 17 followed a diet and lifestyle program called Healthy Habits for Life (HHL). Researchers monitored changes in their muscle mass.

while the semaglutide group achieved greater weight loss, the proportion of that weight loss coming from lean mass was similar between both groups. This indicates the drug’s primary effect is overall weight reduction.

However,when researchers adjusted for overall weight loss,they found a notable correlation. Within the semaglutide group, being older, female, or consuming less protein was associated with greater muscle loss. Furthermore, increased muscle loss in these patients was linked to less improvement in their blood sugar levels, as measured by HbA1c.

“Older adults and women may be more likely to lose muscle on semaglutide, but eating more protein may help protect against this,” said Dr. Melanie Haines, the study’s lead researcher from Massachusetts General Hospital and Harvard Medical School in Boston, Massachusetts. Preserving muscle mass during weight loss is critical.

Haines emphasized that losing too much muscle could diminish semaglutide’s benefits for blood sugar control. Therefore, maintaining muscle mass is likely important for reducing insulin resistance and preventing frailty in individuals with obesity. More research is needed to determine the optimal strategies for fat loss while preserving muscle when using GLP-1 medications.

Frequently Asked Questions

Q: What is semaglutide?

A: Semaglutide is a medication often prescribed for weight loss, belonging to a class of drugs known as GLP-1 agonists.

Q: What is lean mass?

A: Lean mass refers to all the non-fat components of the body, including muscle, bone, organs, and water.

Q: who is at higher risk for muscle loss on semaglutide?

A: According to this study, older adults and women taking semaglutide may be at a higher risk for muscle loss.

Q: How can muscle loss be mitigated?

A: The study suggests that higher protein intake may help prevent muscle loss in individuals taking semaglutide.

What are your thoughts on these findings? Have you or someone you know experienced muscle loss on weight-loss medications? Share your experiences and insights in the comments below.

Could the appetite-suppressing effects of semaglutide inadvertently lead to insufficient protein intake, hindering muscle preservation?

Understanding Semaglutide and its Mechanism

Semaglutide, marketed under names like Ozempic and Wegovy, has become a popular medication for both type 2 diabetes management and weight loss. It belongs to a class of drugs called GLP-1 receptor agonists. these medications mimic the effects of the naturally occurring GLP-1 hormone, which:

Slows gastric emptying, making you feel fuller for longer.

Increases insulin secretion when blood sugar is high.

Suppresses glucagon secretion, preventing the liver from releasing stored sugar.

Potentially impacts appetite regulation in the brain.

While highly effective for weight management, a growing body of evidence suggests a meaningful, frequently enough overlooked side effect: muscle loss. This isn’t just about aesthetics; preserving lean muscle mass is crucial for overall health, metabolism, and long-term weight maintenance.

Why Semaglutide Can Lead to Muscle Loss

The primary mechanism behind semaglutide-induced muscle wasting isn’t directly through muscle tissue itself, but rather through a combination of factors:

1. Calorie Restriction: Semaglutide’s appetite-suppressing effects often lead to substantial calorie deficits. While necessary for weight loss, extreme or prolonged deficits can signal the body to break down both fat and muscle for energy.
2. Reduced Protein Intake: Decreased appetite can also result in lower protein consumption. Protein is the building block of muscle, and insufficient intake exacerbates muscle breakdown.
3. Decreased physical Activity: Some individuals experience fatigue or reduced energy levels while on semaglutide, leading to decreased exercise and further contributing to muscle atrophy.
4. hormonal Changes: GLP-1 receptor agonists can influence other hormones involved in muscle metabolism, potentially promoting catabolism (muscle breakdown). Research is ongoing to fully understand these complex interactions.

The Importance of Muscle Mass

Losing muscle isn’t simply a cosmetic concern. Lean body mass plays a vital role in:

Metabolic Rate: Muscle tissue burns more calories at rest than fat tissue. Losing muscle slows down your metabolism, making it harder to maintain weight loss long-term.

Strength and Function: Muscle is essential for physical function, mobility, and independence.

Insulin Sensitivity: Muscle helps regulate blood sugar levels. muscle loss can worsen insulin resistance.

Bone Density: Muscle supports bone health.

Overall Health & Longevity: Maintaining muscle mass is linked to better overall health and a longer lifespan.

Identifying Muscle Loss While on Semaglutide

It’s crucial to monitor for signs of muscle loss while taking semaglutide. These include:

Decreased Strength: Difficulty performing everyday tasks or noticing a decline in your ability to lift weights.

Reduced Endurance: Feeling more fatigued during physical activity.

Changes in Body Composition: A disproportionate loss of muscle compared to fat. This can be assessed through methods like:

Bioelectrical Impedance Analysis (BIA): A common method to estimate body composition.

DEXA Scan (Dual-Energy X-ray Absorptiometry): A more accurate, but also more expensive, method.

Regular Weigh-ins & Measurements: Tracking weight, waist circumference, and potentially using a measuring tape to assess muscle size.

Loose Skin: While some skin laxity is expected with weight loss, excessive looseness can indicate significant muscle loss.

strategies to Preserve Muscle Mass on Semaglutide

Fortunately, muscle loss isn’t certain. Here’s how to mitigate the risk:

1. Prioritize Protein Intake: Aim for at least 1.0-1.2 grams of protein per kilogram of body weight (or 0.45-0.55 grams per pound). Good sources include lean meats, poultry, fish, eggs, dairy, legumes, and protein supplements.
2. Strength Training: Engage in resistance exercise at least 2-3 times per week. Focus on compound movements (squats,deadlifts,bench press,rows) that work multiple muscle groups.
3. Moderate Calorie Deficit: work with a healthcare professional to establish a sustainable calorie deficit that promotes weight loss without excessive muscle breakdown. Avoid crash dieting.
4. Stay Hydrated: Drinking enough water is crucial for overall health and muscle function.
5. Monitor and Adjust: Regularly assess your body composition and adjust your diet and exercise plan as needed.
6. Consider Creatine Supplementation: Creatine can help preserve muscle mass and strength, particularly during calorie restriction. Consult with your doctor before starting any new supplement.
7. Vitamin D Optimization: Adequate Vitamin D levels are linked to muscle function. Have your levels checked and supplement if necessary.

Real-World Considerations & Case Studies

Many patients starting semaglutide report initial enthusiasm with rapid weight loss. However, without proactive measures, this can be followed by concerns about muscle weakness and a plateau in their progress.

A recent case study (details available through