Injectable Peptides: Out of the Back Alley and Into the Light? Berkley Lifesciences 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 Compounded "semaglutide" is not FDA approved semaglutide.com Compounded "semaglutide" is not FDA approved semaglutide.com FDA takes first step in possible reversal of ban on some peptides The Washington Post