The USA Food and Drug Administration stated on Tuesday that warning letters have been sent to four companies for selling unapproved GLP-1 drugs, including semaglutide and tirzepatide, which are active ingredients in popular diabetes and weight loss medications. After a review of the websites of Xcel Peptides, Swisschems, Summit Research, and Prime Peptides by the USA health regulatory agency in October, warning letters were issued last week to these companies. The websites indicated that their products were labeled as "for research use only" or "not for human Consumer or clinical use." However, evidence collected by the USA Food and Drug Administration suggests that these products are actually intended for use as human drugs.