Trying to get a bargain on your GLP-1 medication might come with some added danger. Compounded copycats of the blockbuster drug tirzepatide, the active ingredient in Mounjaro and Zepbound, could possibly contain concerning byproducts.
On Thursday, Eli Lilly, the maker of tirzepatide, issued a warning to the public. The company claims to have identified “significant levels of an impurity” in compounded drugs that combine tirzepatide with vitamin B12. Health authorities have previously advised people to stay away from these customized versions of GLP-1s.
“People receiving tirzepatide-B12 products from compounders, telehealth companies, medspas, or anyone else should be aware that they may be using a potentially dangerous product with unknown risks,” the company stated.
Compounded risks
Compounded drugs are custom-made formulations of existing medications that can be produced by pharmacies under certain circumstances.
For a time, pharmacies were given wider latitude to make GLP-1 drugs like semaglutide (Ozempic and Wegovy) and tirzepatide that were in shortage. People haven’t flocked to compounded GLP-1s just because they’re available. They’ve also been substantially cheaper out of pocket than the official versions, which often aren’t covered by private or public insurance carriers (Wegovy’s list price was initially around $1,400 a month). These shortages have long since ended, however.
Some compounding pharmacies and distributors claim they can still sell these products if they’re customized to customers’ specific health needs (this is actually the usual function of compounding pharmacies). Often, these outlets will claim to produce personalized GLP-1s combined with vitamins like B12 or other ingredients, some even marketing them as improved versions.
The FDA isn’t buying that justification, though, and it’s tried to clamp down on the continued and likely illegal mass marketing and distribution of compounded GLP-1s. Both Eli Lilly and Novo Nordisk (the makers of semaglutide) have also pursued legal action against several compounded distributors, with many lawsuits still winding through the courts.
As part of Eli Lilly’s campaign against compounded GLP-1s, the company conducted testing of products marketed to contain tirzepatide and B12. In these products, it reportedly identified impurities that may have resulted from a chemical reaction between the two ingredients. The company added that it has sent its results to the FDA.
While B12 is a common addition to compounded GLP-1s, it’s far from the only one.
“Mass compounders and supposed ‘personalizers’ seeking to circumvent the law are also mixing tirzepatide with glycine, pyridoxine, niacinamide, carnitine, or other chemicals, creating a range of new and untested combination drugs,” the company stated in its warning Thursday.
What to make of compounded GLP-1s
Obviously, Eli Lilly has a vested interest in putting down any unauthorized copycats of its hugely popular weight loss drugs. But that doesn’t mean the company is wrong to do so.
While compounding pharmacies do have their place in medicine, they certainly weren’t intended to serve as a gray market offshoot for FDA-approved drugs—drugs that have to undergo a lengthy process to vet their safety and effectiveness. This process isn’t necessarily perfect, but there are a lot more safeguards in place than there are for compounded drugs.
The FDA notes it has collected reports of compounded GLP-1s not being refrigerated adequately or being made with poor-quality ingredients. In some cases, people have received compounded GLP-1s labeled to come from pharmacies that didn’t actually compound the drug or seemingly don’t even exist. Adverse events linked to compounded GLP-1s include redness, site swelling, pain, and a red lump at the injection site, according to the FDA.
Earlier this week, the company Hims, arguably the best-known source of compounded GLP-1s, announced that it would stop marketing these drugs as part of a truce formed with Novo Nordisk. This new agreement might signal the beginning of the end for compounded GLP-1s, both due to legal pressure from the FDA and GLP-1 makers as well as the steady drop in list prices for authorized products, which are now finally close to the prices for compounded versions.
It’s always more of a gamble to take these drugs over the real thing. Soon enough, it may be a lot harder to even procure them in the first place.
