AOD-9604

Overview

AOD-9604 is a 16-amino-acid synthetic peptide corresponding to the C-terminal fragment of human growth hormone (residues 177-191) with an additional N-terminal tyrosine. Developed by Metabolic Pharmaceuticals (Australia) to isolate a purported 'lipolytic' activity of GH without GH-receptor-mediated growth or diabetogenic effects. AOD-9604 is NOT FDA-approved for any indication; controlled human trials for obesity did not demonstrate clinically meaningful weight loss, and obesity development was terminated in 2007.

Mechanism of Action

The original preclinical hypothesis was that hGH(177-191) retains a lipolytic activity via a non-GH-receptor pathway, with some rodent data implicating β3-adrenoceptor expression and cAMP signaling in adipocytes. This mechanism is disputed and has not been robustly reproduced in controlled human studies — Phase 2 trials showed no significant effect on body weight versus placebo. AOD-9604 does not measurably raise serum IGF-1 and does not impair glucose tolerance in human safety studies, which is consistent with lack of GH-receptor agonism but does not establish clinical lipolytic efficacy.

Research Summary

Preclinical: Ng et al. (Horm Res 2000) and Heffernan et al. (Int J Obes 2001; Endocrinology 2001) reported reduced body weight gain and increased fat oxidation in rodent models. Clinical: Six randomized, double-blind, placebo-controlled Phase 1/2 trials across ~900 subjects established a safety profile indistinguishable from placebo (Stier et al., J Endocrinol Metab 2013) but did NOT demonstrate clinically meaningful weight loss; a 24-week Phase 2b trial (~536 subjects) failed its primary efficacy endpoint and obesity development was terminated in 2007. Later preclinical work explored intra-articular use in a rabbit osteoarthritis model (Kwon & Park 2015); no adequately powered human OA trial has been published. Regulatory: AOD-9604 is NOT FDA-approved. It was placed on the FDA interim 503A Category 2 list (may present significant safety risk) in 2023, removed from Category 2 in September 2024 after the nominator withdrew, and at the December 4, 2024 PCAC meeting the committee voted AGAINST inclusion on the 503A Bulks List. Widely sold for 'weight loss' and osteoarthritis via grey-market and compounding channels without adequate human efficacy data.

Dosing Information

Reported Side Effects

• Injection site reactions — redness, soreness
• Headache
• Overall adverse-event rate in Phase 1/2 trials was indistinguishable from placebo
• Long-term safety in chronic non-clinical use is unknown

Research References

• The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and β(3)-AR knock-out mice (Heffernan et al., Endocrinology) (2001)
• Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone (Ng et al., Hormone Research) (2000)
• Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment (Heffernan et al., Int J Obes Relat Metab Disord) (2001)
• Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model (Kwon & Park, Ann Clin Lab Sci) (2015)
• AOD9604 — Wikipedia (development history, terminated Phase 2b obesity program, and regulatory background) (2024)