The U.S. Food and Drug Administration said on Tuesday it has sent warning letters to four companies for selling unapproved versions of GLP-1 drugs including semaglutide and tirzepatide, the active ingredients in popular diabetes and weight-loss drugs.
The letters were issued to Xcel Peptides, Swisschems, Summit Research, and Prime Peptides last week after the U.S. health regulator conducted a review of their respective websites in October.
