Retatrutide
Retatrutide is a triple agonist of the GLP-1, GIP and glucagon receptors, developed and studied in clinical trials by Eli Lilly. Published phase 2 trials reported notable reductions in body weight over several months of treatment in participants with obesity, with a side-effect profile that was mainly gastrointestinal, consistent with other molecules in this class.
Tirzepatide
Tirzepatide, a dual GIP/GLP-1 agonist, has a more advanced body of phase 3 clinical trials than retatrutide, which has led to marketing authorizations in several countries for specific metabolic indications. Published data document its effect on body weight and glycemic control.
BPC-157
BPC-157 has a substantial body of preclinical studies (animal models) documenting effects on tissue healing, gastrointestinal protection and angiogenesis. Published, controlled human data remain, to date, markedly more limited than preclinical data — the reference scientific literature clearly distinguishes between these two levels of evidence.
GHK-Cu
GHK-Cu is one of the longest-studied peptides in the field, with publications dating back to the 1970s. The literature covers both cellular model studies and certain human studies involving topical application, in the context of dermatological research on tissue regeneration and collagen synthesis.
Key takeaways
The level of scientific evidence varies greatly from one compound to another — some have advanced-phase clinical trials, while others rely mainly on preclinical data or older literature. We encourage you to consult the source publications directly (PubMed, ClinicalTrials.gov) to form your own opinion on the state of research for a given compound.