What Is AOD-9604?
AOD-9604 (Anti-Obesity Drug 9604) is a synthetic peptide consisting of a fragment of the human growth hormone molecule — specifically the C-terminal end of the HGH amino acid sequence (residues 177–191). This fragment was identified as the portion of HGH responsible for its fat-metabolizing effects, while being separated from the portions responsible for muscle building, insulin resistance, and other anabolic effects of full HGH.
The Key Distinction from HGH
Full human growth hormone has broad effects: it builds muscle, promotes fat breakdown, raises blood sugar through insulin resistance, and elevates IGF-1. AOD-9604 is designed to isolate only the fat-metabolizing effects. It does not raise IGF-1, does not appear to cause insulin resistance, and does not carry the muscle-building (and potential cancer-promoting) effects associated with IGF-1 elevation from full HGH administration.
Mechanism of Action
AOD-9604 appears to stimulate lipolysis (fat breakdown) and inhibit lipogenesis (new fat formation) through mechanisms that mimic the fat-specific actions of HGH. Animal studies have shown meaningful reductions in body fat with AOD-9604 administration without corresponding effects on blood sugar or muscle tissue.
Relevance to GLP-1 Users
AOD-9604 is sometimes used by people on GLP-1 therapy who want to specifically accelerate fat loss without the potential downsides of growth hormone-related peptides. Because GLP-1 creates a calorie deficit through appetite suppression, pairing it with a compound that promotes fat mobilization is theoretically appealing for people who want to ensure weight loss is predominantly fat rather than mixed tissue.
Development History
AOD-9604 was originally developed as a pharmaceutical anti-obesity drug and reached Phase 2 clinical trials in the early 2000s. The trials showed safety but mixed efficacy results at the doses studied, and pharmaceutical development was discontinued. It has since migrated into the research peptide market.