Slimming jabs like Wegovy and Mounjaro have been hailed as game-changers for weight loss.
But here’s the catch — what if you’re losing more than just fat?
Researchers say that while GLP-1 drugs are highly effective for shedding weight.
Around 25–40% of that loss can come from lean body mass — meaning muscle. And that matters.
Why? Because muscle isn’t just about strength. It helps burn calories and supports overall metabolic health.
Now, a new early-stage study suggests there may be a way to fix that trade-off.
Scientists tested a drug called apitegromab, a monoclonal antibody that blocks myostatin — a protein that normally slows muscle growth.
In a trial of 102 people using tirzepatide (the active drug in Mounjaro), participants were split into two groups.
One received apitegromab, the other a placebo.
What Were The Results?
Both groups lost similar overall weight. But the difference was in what they lost.
Those taking apitegromab lost significantly less muscle — about 1.6kg compared to 3.5kg in the placebo group.
That’s a 55% improvement in muscle retention.
Professor Alexander Miras called the findings “very important,” noting that preserving muscle could mean better strength and daily function for patients.
But experts also caution it’s early days. As Prof Naveed Sattar put it, “It’s too early to say whether this translates into better health outcomes.”
So what’s the real takeaway? Weight loss might be getting smarter — but the real goal isn’t just losing kilos… it’s keeping what keeps you strong.
