Why Muscle Loss During Weight Loss Matters
Millions of people are using semaglutide-based medications like Ozempic or Wegovy to lose weight. But what many don’t realize is this: up to 35% of the weight lost may come from muscle, not just fat.
Muscle is critical for everyday strength, bone health, metabolism, and energy. When you lose too much muscle, you may feel weaker, get tired faster, and even slow down your metabolism — making it harder to keep the weight off long term.
That’s why scientists at Regeneron launched the COURAGE trial — to test if combining semaglutide with another medication could help people keep their strength while losing weight.
What Is Semaglutide and How Does It Work?
Semaglutide is part of a group of medicines called GLP-1 receptor agonists. Here’s what that means in plain English:
When you eat, your body releases a hormone called GLP-1. It tells your brain: “You’re full!” Semaglutide mimics that hormone. It helps people:
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Feel full faster
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Eat less
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Lose weight more easily
It’s like having a louder voice inside your brain saying, “I’m satisfied, no need for more.”
While powerful for fat loss, semaglutide isn’t picky. It causes the body to lose both fat and muscle. That’s where this new study comes in.
Introducing Trevogrumab: The Muscle Guardian
Trevogrumab is a special kind of medicine that blocks myostatin, a protein that slows down muscle growth. Think of myostatin like a “muscle brake” — it tells your body to stop building muscle.
When trevogrumab blocks that brake, your body is allowed to:
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Keep more muscle during weight loss
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Possibly rebuild strength even while slimming down
In the COURAGE trial, researchers combined semaglutide + trevogrumab, and in some cases added a third drug called garetosmab (which blocks another growth-limiting protein called activin A).
Inside the COURAGE Trial: What Did the Scientists Do?
Here’s what the study involved:
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People with obesity joined the trial and received semaglutide.
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Some also got trevogrumab, with or without garetosmab.
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Scientists measured what type of weight was lost — fat or muscle — over time.
The goal? See if trevogrumab could protect lean muscle mass while semaglutide helped people lose fat.
And the early results? Promising.
What They Found: Less Muscle Loss, More Fat Loss
Participants who received just semaglutide lost weight — but around 35% of that was muscle.
However, when semaglutide was paired with trevogrumab, researchers saw:
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More fat loss
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Much less muscle loss
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50% to 80% of the usual lean mass loss was prevented
In simple terms: the medicine combo allowed people to lose the weight they wanted, but keep more of their strength and energy.
Why This Could Be a Game Changer
Losing weight is hard. Keeping it off is harder. And if you lose too much muscle along the way, it can hurt your body instead of helping it.
This study shows a possible new path:
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A treatment that targets fat loss
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While preserving muscle strength
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With the potential to improve long-term health outcomes
This could be especially useful for older adults, athletes recovering from weight gain, or anyone wanting to avoid weakness or fatigue during weight loss.
Is This Available Now? What You Need to Know
Not yet.
This was an interim result from a Phase 2 trial — meaning it's halfway through a multi-stage study. The drugs (trevogrumab and garetosmab) are not approved for public use yet.
Here’s what we still don’t know:
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Will this combo work long-term?
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Is it safe for all types of people?
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Will it be affordable or covered by insurance?
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Are there side effects we haven’t seen yet?
That’s why scientists are continuing the trial — to answer these important questions.
What You Can Do Today to Protect Your Muscle
Even without new medications, there are simple ways to keep your muscle while losing fat:
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Lift weights or do bodyweight exercises
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Eat enough protein (like eggs, chicken, beans, and nuts)
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Get plenty of rest and sleep
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Stay active with daily walking or movement
These strategies help signal to your body: “Keep the muscle, just burn the fat.”
What’s Next for This Research?
The COURAGE trial will continue collecting data. Scientists will be looking at:
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More people with different backgrounds
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Long-term effects of the drug combo
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Safety, muscle performance, and weight maintenance
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Potential for FDA review and approval
If the results keep trending upward, this could become the future of obesity treatment — helping people lose weight without feeling weak or tired.
Final Thoughts: A Hopeful Path Ahead
Losing weight is about more than just the number on the scale. It’s about staying strong, feeling good, and protecting your health.
This study offers a new option — a possible future where you don’t have to trade strength for slimness.
Semaglutide has already changed the way we approach obesity. With new support from drugs like trevogrumab, we might be looking at a new chapter in medicine — one where your body can hold on to what matters most while shedding the rest.
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