Peptides Studied for Weight Loss

Weight loss is the area where peptide research has produced the clearest clinical wins — and the starkest evidence gaps. Semaglutide, tirzepatide, and liraglutide are FDA-approved, backed by large clinical programs, and represent genuine breakthroughs in obesity medicine.

Retatrutide, Eli Lilly's investigational triple agonist (GIP/GLP-1/glucagon), is the most advanced next-generation candidate, with Phase 2 data showing up to 24.2% body weight loss and a large Phase 3 program (TRIUMPH) underway. It is not yet approved.

The amylin wave is the next major branch. CagriSema combines cagrilintide with semaglutide, cagrilintide is a standalone long-acting amylin analogue, and amycretin is a single-molecule GLP-1 + amylin candidate. These are not approved yet, but they belong in the same obesity evidence map.

AOD-9604 tells a very different story. Designed as a fat-metabolism fragment of human growth hormone, it showed promise in early studies but failed its pivotal Phase IIb trial. It remains widely sold as a research compound despite that failure.

This page exists to make those differences visible. The evidence bars below each profile tell the story at a glance — but the full profiles are worth reading to understand the spectrum from FDA-approved drugs to investigational candidates to failed research compounds.