Tirzepatide
Approved pharmaceutical dual GIP/GLP-1 therapy
Tirzepatide is a dual GIP and GLP-1 receptor agonist approved for type 2 diabetes and chronic weight management, with additional label expansion depending on current product status. It is a prescription drug, not a research peptide.
The evidence base is strong and comes from large SURPASS and SURMOUNT programs. Its long half-life means side effects, dose escalation, missed doses, and washout periods unfold more slowly than people may expect.
Retatrutide
Late-stage investigational triple agonist
Retatrutide activates GLP-1, GIP, and glucagon receptors. The glucagon component is the key differentiator from tirzepatide and may contribute to greater energy-expenditure and liver-fat effects, but it may also change tolerability.
The evidence is strong for an investigational compound but not the same as an approved product. Phase 2 results are impressive, while Phase 3 and final labeling determine the real risk-benefit profile. Don't treat gray-market retatrutide as equivalent to clinical-trial retatrutide.