FDA Compliance for Peptide Therapy and BPC 157 Holt Law Beyond the Headlines: FDA Warning Letters to GLP 1 Compounders Spencer Fane 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 FDA to weigh easing limits on unproven peptides favored by RFK Jr. and MAHA supporters PBS News