GLP-1 agonist drugs have forever changed the weight-loss landscape. Ordinary people and celebrities alike have undergone dramatic and rapid transformations while taking them.

While GLP-1 users often see remarkable fat loss, many also lose significant quantities of lean mass. BioLongevity Labs is hoping to change that.

Studies have indicated muscle loss accounts for 25%–39% of total weight lost in patients taking GLP-1 medications. For the sake of comparison, muscle loss accounts for 10%–30% of weight loss in patients who lose weight through calorie restriction alone. Most experts believe that the large amount of muscle lost is due to the magnitude and speed of GLP-1-driven weight loss.

When the body loses weight rapidly, it burns muscle tissue in addition to fat. GLP-1 patients often have greatly reduced appetites, so they may not eat enough to sustain existing muscle mass.

For most people prescribed GLP-1s, weight loss is essential for optimal health. However, loss of muscle can lead to a slowed metabolism, reduced strength, and even chronic pain.

What if there were a way to safely support muscle mass in GLP-1 users? According to BioLongevity Labs co-founder Jay Campbell, there’s a method already in the works. The company has developed FLGR242, an analog of the natural glycoprotein follistatin.

Follistatin inhibits the function of myostatin, one of the main proteins that limit muscle growth. In other words, it supports increased muscle growth without supporting an increase in fat mass.

To date, several variants of natural follistatin, including Follistatin 314, 344, and 347, have been used in medical research. FLGR242 is designed to amplify the benefits of follistatin supplementation to support muscle preservation in people taking GLP-1s.

“Our product is unlike Follistatin 314, 344, or 347, as it’s a recombinant form with an albumin binder that extends the half-life to 19 days,” Campbell explains. “This product will be essential for people using GLP-1 peptides for fat loss, as it helps prevent muscle degradation, or catabolism, due to its unique ability to increase skeletal muscle protein.”

Older forms of follistatin have very short half-lives by comparison. For example, the half-life of Follistatin 344 is around two hours. This means that to see any meaningful impact, a patient would have to administer very frequent doses.

For many patients taking GLP-1s, treatment is long-term or even indefinite. Thanks to FLGR242’s much longer half-life, patients will be able to achieve a steady concentration without having to dose at intervals that are unsustainable. That’s not the only benefit of FLGR242. Campbell says it may help patients avoid some of the less desirable side effects that come with older forms of follistatin.

“Most myostatin inhibitors don’t just touch myostatin itself,” he says. “They also interact with GDF11, activins, and bone morphogenic proteins (BMPs). This can lead to bone weakness and unwanted vascular effects. This is why we created FLGR242, a fragmented and modified version of Follistatin 344.”

BioLongevity Labs’ FLGR242 is still being used for research purposes, so it’s not yet available for therapeutic use. Thus far, it seems to be showing superior results with fewer side effects.

“Our follistatin doesn’t break down in the body as easily as the previous version and has an even more pronounced effect on myostatin,” Campbell says. “It’s an incredible compound which stimulates muscle growth without affecting other cellular systems or organs.”

So will patients taking GLP-1s one day be prescribed FLGR242? Maybe. If all goes as planned, a currently vulnerable subset of the population may be headed for a stronger, healthier future.