The U.S. Food and Drug Administration said it has seized “thousands of units” of counterfeit Ozempic, the diabetes drug widely used for weight loss, that had been distributed through legitimate drug supply sources.

The FDA and the drug’s maker, Novo Nordisk, are testing the shots. They do not yet have information about the drugs' identity, quality or safety, according to a statement. Five illnesses have been linked to the fake shots, but none have been serious, the FDA said Thursday.

Some of the fake 1 milligram semaglutide shots may still be for sale, FDA said. In addition to the drug itself, the needles, pen labels, carton and accompanying health care information are also counterfeit, the agency said.

It said the counterfeits were labeled with the lot number NAR0074 and serial number 430834149057.

FDA advised retail pharmacies to buy authentic Ozempic only through authorized distributors and for patients to get it only through state-licensed pharmacies.

Consumers can report suspect Ozempic packages by calling 800-332-1088 or by contacting a state complaint coordinator.