The US Food and Drug Administration has questioned the evidence as demand surges for the compounds promoted for sleep, muscle growth, and anti-ageing.

Peptides, a class of compounds increasingly marketed as wellness treatments, have exploded in popularity in recent years, moving from niche bodybuilding and biohacking circles to now being promoted for everything from weight loss to longevity.

But as questions grow over whether many of them are safe or work as advertised, regulators in the United States are set to decide whether some of them should become available through licensed pharmacies.

The Pharmacy Compounding Advisory Committee of the US Food and Drug Administration (FDA) will meet on Thursday and Friday to decide whether the seven peptides can be made by licensed compounding pharmacies for patients with prescriptions.

Peptides are short chains of amino acids that occur naturally in the body and help regulate a wide range of biological processes. Some peptide-based medicines, including GLP-1 weight-loss drugs such as Ozempic and Wegovy, have become household names in recent years. But the seven peptides under review this week are a different group of compounds marketed for a broad range of conditions.

They include BPC-157, TB-500 and KPV, which are promoted for uses including ulcerative colitis, wound healing and inflammatory conditions, as well as others that are sold as solutions for obesity, migraines, chronic pain, insomnia and opioid withdrawal.

The review comes as peptides have been propelled into the mainstream by social media influencers, the rise of the online beauty trend known as “looksmaxxing”, and repeated endorsements from Health Secretary Robert F Kennedy Jr, who has said he has used them with “really good effect” and argued that restrictions have pushed consumers into an unregulated grey market.

The trend has concerned scientists at the FDA, who have repeatedly questioned the evidence behind many peptides. In documents ahead of this week’s meeting, the agency said there is little evidence supporting the safety or effectiveness of the seven compounds under review, citing inadequate human clinical trials and concerns about their quality, stability and consistency.

But despite those concerns, demand has continued to soar. The compounds are marketed through wellness clinics and influencers for everything from building muscle and losing weight to slowing the ageing process. Reddit forums dedicated to peptide use have become hubs where thousands of users compare suppliers, discuss dosing and share personal experiences.

Industry groups argue that demand is why the FDA should make it easier for licensed pharmacies to compound peptides, thereby enabling greater oversight of prescriptions and quality standards.

But even the makeup of the advisory committee itself is controversial.

According to AP, seven of the panel’s 14 members have ties to businesses or clinics involved in peptide therapies. They include doctors who run clinics selling peptide injections and promote them on social media, and pharmacist and Tennessee State Senator Bobby Harshbarger, whose family owns a pharmacy that sells compounded medications. His mother, Republican US Congressional Representative Diana Harshbarger, urged Kennedy last year to loosen FDA restrictions on peptides.

The Department of Health and Human Services has defended the panel, saying every member underwent the same ethics review required for FDA advisory committees and that anyone who failed to meet federal ethics requirements was removed from consideration.

While the panel’s recommendations aren’t binding, they are expected to help shape the FDA’s final decision.