The Food and Drug Administration is warning patients about drug compounding in medications marketed for weight loss.
Ozempic, Rybelsus and Wegovy are currently the only three FDA-approved semaglutide products.
However, the agency said it's aware of cases in which patients have received compounded versions of semaglutide. Compounding is the process of combining, mixing or altering ingredients in a drug.
Federal health officials say some medications being sold may not contain the same active ingredient as FDA-approved semaglutide products. Instead, they may have been created with salt substitutes.
"Products containing these salts, such as semaglutide sodium and semaglutide acetate, have not been shown to be safe and effective," the FDA warns.
The FDA said it has received "adverse event reports" after patients used compounded semaglutide. The agency did not detail what adverse reactions the patients reported.
How to know if your product is FDA-approved
Ozempic, Rybelsus and Wegovy require a prescription. Websites that offer the drugs without a prescription should be a cause for concern.
The FDA says patients should also make sure their prescriptions are filled at "state-licensed pharmacies or outsourcing facilities registered with FDA." While online pharmacies may cause some concern, there are many legitimate providers. Consumers can look up which online pharmacies are licensed by going to the FDA's website.
