GLP-1 and the Potential for Massive Muscle Loss: What You Need to Know

Obesity is one of the biggest health challenges of our time, with 42% of Americans classified as obese. Certain groups—such as adolescents and specific racial demographics—face even higher obesity rates. But change is on the horizon. GLP-1 receptor agonists, a class of drugs originally developed for diabetes management, are now being widely used to promote weight loss. With their increasing popularity and effectiveness, it’s possible that obesity rates could decline significantly in the coming years—provided these medications remain accessible and safe.

However, while GLP-1 drugs offer a promising solution for weight loss, they come with a major concern: the risk of significant muscle loss.

Do GLP-1 drugs come with trade-offs?

The Connection Between GLP-1 Drugs and Muscle Loss

Sarcopenia—the age-related loss of muscle mass and strength—is already a critical issue, particularly for people in their 60s and beyond. On average, adults lose 8% to 17% of their muscle mass per decade, and women tend to lose muscle at a faster rate than men. That means if you’re in your 40s or 50s, you’re already experiencing some degree of muscle decline, even if you don’t notice it yet.

GLP-1 medications may accelerate this loss. Studies suggest that when people lose 20% to 30% of their body weight using these drugs, a significant portion of that weight loss comes from muscle. But how much muscle is being lost, and how does it impact overall strength and function? That’s where things get complicated.

Why Lean Body Mass is a Poor Measure of Muscle Loss

Many studies use lean body mass (LBM) as a proxy for muscle mass, but this metric includes more than just muscle—it also accounts for water, organs, and other non-fat tissues. This makes it an imprecise way to track muscle loss. The gold standard for accurately measuring muscle mass is MRI or advanced imaging, but these tests aren’t commonly performed in weight loss studies.

MRI scan showing muscle vs. fat composition

If someone loses 30% of their body weight and 75% of that loss comes from muscle, that’s a serious problem. However, the actual breakdown of fat loss vs. muscle loss remains unclear because most studies don’t use precise muscle measurement techniques.

Do GLP-1 Recipients Lose Strength?

That’s the big unknown. While losing weight can make movement and exercise easier, it doesn’t necessarily mean you maintain—or improve—your strength. There is no standardized testing for key strength indicators such as:

• Squats

• Bench press

• Shoulder press

If muscle mass is declining significantly, it’s possible that strength is decreasing too. Without proper assessment, people using GLP-1 drugs may feel lighter but weaker—putting them at risk for frailty, injury, and reduced mobility over time.

FutureFitYou: Take the Guesswork Out of Your Fitness

This is where FutureFitYou comes in. Our Fitness Checkpoint provides a science-backed assessment of your Strength, Stability, and Cardio fitness. Instead of relying on assumptions, you can track real data on your body’s capabilities and ensure you’re preserving muscle and strength as you lose weight.

A Fitness Checkpoint involves performing exercises in each category and benchmarking your results against age- and gender-specific standards. Whether you are a Pure Beginner, Advanced Beginner, or Advanced, the Checkpoint meets you where you are and helps you improve from there.

Person performing a squat with overlayed benchmarking stats to illustrate fitness assessment.

The Bottom Line

GLP-1 drugs offer a powerful tool for weight loss, but they come with the risk of unintended muscle loss—which could have serious long-term consequences. If you’re using or considering GLP-1s, you need a plan to preserve muscle mass and maintain strength. A FutureFitYou Fitness Checkpoint can help you understand where you stand and what to work on, ensuring your weight loss is both effective and sustainable.

Are you losing fat or muscle? The only way to know is to measure. Take control of your health today with a FutureFitYou Checkpoint.