FDA warning letters target marketers of unapproved weight loss drugs RAPS FDA to weigh easing limits on unproven peptides FDA's Overreach on Compounded Peptides The FDA just put peptides like BPC 157, TB 500, and KPV on the clock. , As a compounding pharmacist, this is literally my world and most people dont understand the regulatory nuance behind what The FDA has issued warning letters to multiple companies marketing compounded Retatrutide, an investigational drug from Eli Lilly still in Phase II trials. While early studies have shown promising weight loss results, Retatrutide