What the Research Found
Research on AOD-9604 falls into three phases: laboratory and animal work in the 1990s and early 2000s, human trials sponsored by the developer, and later studies on joints and on detection in sport.
Fat Metabolism in Animals
- Rat fat tissue (Biochem Mol Biol Int, 1993): the hGH 177-191 fragment reduced the making of new fat but did not directly break down existing fat in isolated fat pads.
- Obese mice (Biochem Mol Biol Int, 1994): in genetically obese mice the fragment lowered weight gain and fat mass.
- Obese rats, by mouth (Horm Res, 2000): after 19 days of oral treatment, obese Zucker rats gained less than half as much weight as untreated rats, 15.8 g against 35.6 g. Fat breakdown rose and insulin sensitivity did not change.
- Obese mice, two weeks (Int J Obes, 2001): continuous delivery reduced weight gain, raised fat burning and blood glycerol, and did not cause high blood sugar. The peptide did not bind the growth hormone receptor or make cells multiply.
Looking for the Mechanism
A 2001 study in Endocrinology found that AOD-9604 increased beta-3 adrenergic receptor levels in fat tissue and that its long-term effect on body weight disappeared in mice without this receptor. In the same knockout mice, a single dose still boosted fat burning, which suggests the fragment works through more than one route.
Human Trials
- Six trials, 2001 to 2007: randomised, double-blind and placebo-controlled, with about 900 adults in total. They ranged from single doses to 24 weeks of daily tablets.
- Efficacy: a 12-week trial reported modest weight loss in the 1 mg group. The 24-week OPTIONS trial with 536 participants found no significant difference from placebo.
- Safety (J Endocrinol Metab, 2013): across the trials, side effects were similar to placebo, IGF-1 did not rise, glucose tolerance was unaffected and no antibodies against the peptide were detected. No serious adverse events were linked to the drug.
Cartilage Research
In a 2015 study of 32 rabbits with damaged knee joints, injections of AOD-9604 into the joint improved cartilage scores, and the combination with hyaluronic acid worked best. This remains a single small animal study and has not been tested in people.
Detection in Sport
A 2013 study showed that AOD-9604 does not interfere with the standard blood test for growth hormone doping. Belgian authorities reported seized preparations in 2014. In 2015 a U.S. laboratory published a urine test able to detect very small amounts, identified six breakdown products and confirmed the peptide in confiscated vials.
Gaps in the Evidence
- The main human trial was negative for weight loss.
- The human safety data come from oral tablets, not from other forms sold today.
- Most studies were funded or run by the developers.
- Reviews published in 2026 in Sports Medicine and Frontiers in Endocrinology pointed out the lack of independent human data for growth hormone fragments sold as research chemicals.
Summary
AOD-9604 changed fat metabolism in rodents and looked safe in short human trials, but it did not produce meaningful weight loss in the decisive study. Beyond that, the evidence rests on a small number of animal experiments.
References
- Wu Z, Ng FM. Antilipogenic action of synthetic C-terminal sequence 177-191 of human growth hormone. Biochem Mol Biol Int. 1993;30:187-196. PMID 8358331
- Natera V, Jiang WJ, Ng FM. Effect of hGH 177-191 on lipid metabolism in ob/ob mice. Biochem Mol Biol Int. 1994;33:1011-1021. PMID 7987248
- Ng FM, et al. Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Horm Res. 2000;53:274-278. PMID 11146367
- Heffernan MA, et al. Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. Int J Obes Relat Metab Disord. 2001;25:1442-1449. PMID 11673763
- Heffernan M, et al. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology. 2001;142:5182-5189. PMID 11713213
- Wilding J. AOD-9604. Curr Opin Investig Drugs. 2004;5:436-440. PMID 15134286
- Stier H, Vos E, Kenley D. Safety and tolerability of the hexadecapeptide AOD9604 in humans. J Endocrinol Metab. 2013;3:7-15. doi:10.4021/jem157w
- Orlovius AK, et al. Effects of the hGH fragment AOD9604 on the WADA hGH isoform immunoassays. Drug Test Anal. 2013;5:850-852. PMID 24124033
- Vanhee C, et al. Identification of AOD-9604 in seized preparations. Drug Test Anal. 2014;6:964-968. PMID 24976118
- Cox HD, et al. Detection and in vitro metabolism of AOD9604. Drug Test Anal. 2015;7:31-38. PMID 25208511
- Kwon DR, Park GY. Effect of intra-articular injection of AOD9604 with or without hyaluronic acid in rabbit osteoarthritis model. Ann Clin Lab Sci. 2015;45:426-432. PMID 26275694
- Thomas A, et al. Determination of growth hormone releasing peptides and related peptides in urine. J Sep Sci. 2016;39:333-341. PMID 26578461
- Mendias CL, Awan TM. Safety and efficacy of approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance. Sports Med. 2026;56:1921-1935. PMID 41966639
- Dominikowski A, Rękoś Z, Olejarz M, et al. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol (Lausanne). 2026;17:1822475. PMID 42395176