niacinamide in semaglutide and Semaglutide for Weight Loss — Dr. Timothy R. Morris, Functional Naturopathic Doctor Why Semaglutide Makes You Tired:

However, the FDA has been cautious with weight loss drugs historically

This GLP-1-mediated delivery of oestrogen to specific tissues enhanced body weight loss and improved glycaemic control and insulin sensitivity relative to either of the hormones alone in DIO mice [96]

GHK-Cu exists as a 1:1 copper(II):peptide complex in which the Cu(II) ion is coordinated by the glycine terminal amino group, the amide nitrogen between glycine and histidine, the histidine imidazole nitrogen, and the lysine side chain amino group in a square planar arrangement

This lends credence to a causal interpretation of the associations discussed above