Despite FDA crackdown, unapproved GLP-1s still threaten the industry

The FDA is putting its foot down on compounded GLP-1 drugs—well, kind of.

The agency has sent “thousands” of letters warning telehealth and pharmaceutical companies about misleading advertising since September, per a March 3 release.

This “crackdown” includes two rounds of warning letters to telehealth firms that sell compounded GLP-1s. The letters warn that advertisements can’t compare a compounded drug to an FDA-approved drug or say a compound has the same active ingredient as an FDA-approved drug. Telehealth companies also can’t imply they are the ones compounding the drug when they’re buying it from another compounder.

More than misleading advertising, though, there’s a potentially bigger concern at hand: Some online sellers might not be legal compounders at all but counterfeit producers using manufacturers that aren’t making them in a sterile manner.

This threatens the reputation of compounding that is done safely and by the book, Todd Harrison, partner and co-chair of the FDA Group at law firm Venable, told us.

“By not paying attention to who these compounding pharmacies are, we run a greater risk of a real safety issue happening,” he said. “That could have an impact on the compounding pharmacy [business] in the long run because all it [takes is] one death and all the cards fall.”

What is compounding? Compounding is when a doctor, pharmacist, or someone supervised by a pharmacist “combines, mixes, or alters ingredients of a drug,” per the FDA. States, not the federal government, lead oversight and regulation of most compounders instead of making these drugs go through the FDA approval process.

Compounds are allowed only under certain conditions, like if a patient is allergic to an ingredient in a branded drug or if a drug is experiencing a shortage. Semaglutide compounds took off during a nationwide shortage that ended Feb. 21, 2025, for instance. They’re technically not allowed to be “essentially copies” of FDA-approved drugs, though the FDA didn’t enforce that restriction during the shortage.

After the shortage ended, companies were supposed to wind down the manufacturing and prescribing of compound semaglutide. Instead, prescriptions increased, research firm IQVIA found in an October 2025 report.

Manufacturers and pharmacies seem to be trying to justify their continued compounding by adding in extra ingredients like B vitamins so the drugs aren’t exact copies (In a note, Eli Lilly recently warned about potential impurity risks of compounds that do this). About 80% of compound semaglutide and tirzepatide (the active ingredient in Lilly’s Zepbound and Mounjaro) prescriptions now have supplemental ingredients, according to the report.

Compounding, at its core, is intended to be “specialized” to the needs of an individual patient, Claudia Lewis, another Venable partner and co-chair of the FDA Group with Harrison, told us.

“It becomes a gray area when it’s mass-produced and mass distributed,” she said.

Safety concerns. It can be dangerous if compounders don’t do things by the book, experts say.

Legit compounding companies buy active pharmaceutical ingredients for their drugs from FDA-registered manufacturers. But some companies are selling “compound” drugs with imported active pharmaceutical ingredients from plants that aren’t inspected or assessed by the FDA, per a page on the agency’s website that was last updated Feb. 4.

Some illegitimate GLP-1 copycats may also contain salt forms of semaglutide with active ingredients that are different from those in the drugs approved for compounding by the FDA, per the agency’s website.

“We don’t know whether these other salts or these alternative salts of the same ingredient have the same benefit,” Harrison said. “In essence, these are unapproved new drugs. And [being a] compounding pharmacy is not a license to create unapproved new drugs.”

Nonprofit research and education organization the Center for Medicine in the Public Interest recommended in a July 2025 report that the FDA increase enforcement against companies doing this. The FDA has sent several warning letters to GLP-1 compounders using salts, as well as companies selling drugs with non-FDA-approved peptide therapies retatrutide and cagrilintide for weight loss, over the last few years.

Lewis predicts the biggest crackdown against illegal compounding will come from the pharmaceutical industry, not the federal government.

Wegovy and Ozempic-maker Novo Nordisk has been particularly aggressive in suing compounders, though it recently made nice and teamed up with one of its biggest telehealth competitors, Hims & Hers. Eli Lilly has been partnering with telehealth provider Ro since 2024.

If and when more companies pursue lawsuits, though, “there’s a million compounders out there,” Lewis said. “So how do you choose which target to pick?”