Weight Loss Peptides Compared: AOD-9604, Semaglutide, Tirzepatide Research
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# Weight Loss Peptides Compared: AOD-9604, Semaglutide, Tirzepatide Research
For Research Purposes Only -- Not Intended for Human or Animal Consumption
Multiple peptide compounds have been studied for their effects on weight and metabolic function, from FDA-approved medications to research compounds.
Semaglutide: The Established Standard
Semaglutide (Ozempic/Wegovy) is a GLP-1 receptor agonist with FDA approval for both type 2 diabetes and obesity. Mechanism: GLP-1 receptor agonism reduces appetite, stimulates glucose-dependent insulin secretion, and slows gastric emptying. Evidence: STEP-1 trial: 14.9% mean weight loss over 68 weeks. SELECT trial: 20% reduction in major adverse cardiovascular events -- the first weight loss drug to show cardiovascular benefit.
Tirzepatide: The New Leader in Efficacy
Tirzepatide (Mounjaro/Zepbound) is a dual GIP/GLP-1 receptor agonist with FDA approval for both type 2 diabetes and obesity. Evidence: SURMOUNT-1: 20.9% mean weight loss at 15 mg/week over 72 weeks -- superior to Semaglutide. SURPASS-2 demonstrated superior outcomes vs Semaglutide 1 mg head-to-head.
AOD-9604: The Research Compound with Failed Phase III
AOD-9604 is the C-terminal fragment of human growth hormone (amino acids 177-191). Mechanism: Proposed lipolytic effects via beta-3 adrenergic receptor activation and cAMP-dependent hormone-sensitive lipase activation. Evidence: Robust lipolytic effects in obese mice; Phase III trial in humans FAILED to demonstrate significant weight loss at 1 mg/day. Received FDA GRAS status (safety, not efficacy). The translational failure illustrates the challenge of translating preclinical findings to clinical outcomes.
Comparative Summary
| Compound | Mechanism | Human Evidence | Regulatory Status | |----------|-----------|----------------|-------------------| | Semaglutide | GLP-1 agonist | Phase III (14.9% WL) | FDA approved | | Tirzepatide | GLP-1/GIP dual agonist | Phase III (20.9% WL) | FDA approved | | AOD-9604 | GH fragment/lipolytic | Phase III (failed) | GRAS (food ingredient) |
References
- Wilding, J.P.H., et al. (2021). Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine, 384(11), 989-1002.
- Jastreboff, A.M., et al. (2022). Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine, 387(3), 205-216.
- Ng, F.M., et al. (2000). Metabolic studies of a synthetic lipolytic domain (AOD9604). Hormone Research, 53(6), 274-278.
See Also: This comparison was last updated in 2024. For 2026 data including [retatrutide's TRIUMPH Phase 3 results](/research/retatrutide-triple-agonist-research) (28.7% weight loss) and [CagriSema's REDEFINE-1 findings](/research/cagrisema-cagrilintide-semaglutide-research) (22.7% weight loss), see our dedicated overviews.