Histamine H2 receptor antagonists, such as cimetidine ( Tagamet ), famotidine ( Pepcid ), and ranitidine ( Zantac ), that are used to treat peptic ulcer disease
Insufficient human clinical data Most research on AOD-9604 has been conducted in animals or short-term human trials, making it difficult to determine its full long-term effects
Excess copper contributes to oxidative stress, inflammation, and potential toxicity, the opposite of what GHK-Cu is supposed to do. Researchers have generally found that GHK-Cu helps regulate copper rather than overload it, but the line between beneficial and harmful copper exposure depends on dose, tissue type, and individual biology
Regulation versus restriction The FDA's 2023 crackdown on compounded peptides curtailed access through licensed pharmacies but did little to dampen demand