The FDA says off-brand versions may not contain the same ingredients.
Federal regulators are warning about safety concerns amid the rising popularity of drugs like Ozempic and Wegovy for weight loss.
The U.S. Food and Drug Administration is warning consumers that off-brand forms of the medications could be unsafe.
The warning comes as many people have reported turning to compounding pharmacies to get cheaper doses of semaglutide, the active ingredient in both Ozempic and Wegovy.
Without insurance coverage, the cost of medications like Ozempic and Wegovy can run more than $1,000 a month.
The FDA said it's received reports of adverse events after people took semaglutide that came from a compounding pharmacy. It did not specify the number of reports or what the adverse events were.
"Patients should not use a compounded drug if an approved drug is available to treat a patient. Patients and health care professionals should understand that the agency does not review compounded versions of these drugs for safety, effectiveness, or quality," the FDA said in a new safety warning this week.
The FDA also said that some compounding pharmacies claiming to sell semaglutide might instead be selling other formulations of the chemical, like semaglutide sodium and semaglutide acetate. Those haven't been shown to be safe or effective, according to the FDA.
Compound versions of drugs are made for individual patients using raw ingredients.
They are not the same as generic drugs, which are FDA-approved and monitored for safety and effectiveness.
There are currently no generic versions of semaglutide medications, including Ozempic and Wegovy.
Insurance coverage for Ozempic and Wegovy varies, depending on everything from a person's medical diagnosis to where they live and their insurance plan.