AOD-9604 (Anti-Obesity Drug 9604) is a synthetic peptide fragment derived from the C-terminal region of human growth hormone (amino acids 176 to 191), with a tyrosine substitution at the N-terminus. Developed in the 1990s by Australian researchers at Monash University, AOD-9604 was designed to isolate the fat-metabolizing properties of HGH without its growth-promoting, IGF-1-elevating, or diabetogenic side effects. Despite promising preclinical results, the peptide failed to demonstrate statistically significant weight loss in its largest clinical trial and was abandoned as a drug candidate in 2007. It remains available as a research compound and continues to attract interest in the peptide community, though its efficacy for fat loss is not supported by robust clinical evidence.
What Is AOD-9604?
AOD-9604 emerged from decades of research into the structure-function relationships of human growth hormone. In the 1990s, Professor Frank Ng and colleagues at Monash University in Melbourne, Australia, identified that the C-terminal fragment of HGH (residues 176 to 191) was responsible for the hormone's lipolytic activity, while the growth-promoting and insulin-antagonistic effects were mediated by different structural regions.
By synthesizing this 16-amino-acid fragment and substituting a tyrosine for the native phenylalanine at position 176, the team created AOD-9604, a peptide that could stimulate fat breakdown without the metabolic complications of full-length growth hormone. The amino acid sequence is Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe, with a disulfide bridge between the two cysteine residues at positions 7 and 14.
Metabolic Pharmaceuticals Ltd., an Australian biotechnology company, licensed the technology and advanced AOD-9604 through clinical development between 2001 and 2007. The peptide has a molecular formula of C₇₈H₁₂₃N₂₃O₂₃S₂, a molecular weight of approximately 1,815 g/mol, and CAS number 221231-10-3.
The proposed benefits of AOD-9604 include:
- Stimulation of lipolysis (fat breakdown) in adipose tissue
- Inhibition of lipogenesis (new fat formation)
- No elevation of IGF-1 levels or interference with glucose metabolism
- No growth-promoting or insulin-antagonistic effects
- Potential support for cartilage repair (emerging research)
It is important to emphasize that AOD-9604 is not approved as a drug by any major regulatory body. The proposed benefits listed above are based primarily on preclinical data and early-phase clinical trials that ultimately did not lead to regulatory approval.
How It Works
Lipolytic Mechanism
AOD-9604 stimulates lipolysis, the hydrolysis of stored triglycerides into free fatty acids and glycerol, in adipose tissue. The primary mechanism involves upregulation of beta-3 adrenergic receptors (beta-3 AR), the major lipolytic receptor in fat cells. In obese mice, both HGH and AOD-9604 increased the suppressed levels of beta-3 AR mRNA to levels comparable with those in lean animals, restoring normal lipolytic responsiveness.
The importance of this pathway was confirmed in knockout studies: beta-3 AR knockout mice were completely unresponsive to the lipolytic effects of both HGH and AOD-9604, demonstrating that the beta-3 adrenergic pathway is essential to the peptide's fat-metabolizing activity.Anti-Lipogenic Effects
In addition to promoting fat breakdown, AOD-9604 appears to inhibit lipogenesis, the de novo synthesis of fatty acids. In vitro studies using isolated adipocytes showed that AOD-9604 simultaneously increased fat oxidation rates while reducing new fat formation. This dual action, stimulating lipolysis while inhibiting lipogenesis, was considered a distinguishing feature of the peptide in early research.
Cartilage Regeneration
More recent preclinical research has explored AOD-9604's effects on cartilage and connective tissue. In vitro studies demonstrated that AOD-9604 promotes proteoglycan and collagen production in chondrocyte cultures and enhances the differentiation of adipose-derived mesenchymal stem cells into bone-forming cells.
A 2015 rabbit model of osteoarthritis found that intra-articular injection of AOD-9604, particularly when combined with hyaluronic acid, improved cartilage integrity and reduced joint degradation compared to controls. These findings are preliminary and have not been replicated in human clinical trials.
Distinction from Full Growth Hormone
The critical advantage of AOD-9604 over exogenous HGH was its selective activity profile. Across six clinical trials involving 893 participants, AOD-9604 did not increase serum IGF-1 levels, did not impair glucose tolerance or carbohydrate metabolism, and did not produce the fluid retention, joint pain, or insulin resistance associated with full-length growth hormone therapy. No anti-AOD-9604 antibodies were detected in any tested participants, indicating low immunogenicity.
Dosage Protocols
AOD-9604 dosing in clinical trials and community use differs substantially. All dosage information below describes unapproved, off-label use.
Clinical trial dosing:
- Phase IIa (METAOD005): 1, 5, 10, 20, or 30 mg/day oral administration for 12 weeks (n=300, 50 per dose group)
- Phase IIb (OPTIONS trial): 0.25, 0.5, or 1 mg/day oral administration for 24 weeks
Community subcutaneous protocols:
- Starting dose: 300 mcg once daily
- Standard range: 300 to 500 mcg per day
- Some protocols escalate to 500 mcg split into two doses (250 mcg AM and 250 mcg before bed) if results plateau after 4 or more weeks
Cycling:
- Standard cycle length: 12 weeks on, followed by 4 to 8 weeks off
- Some users run continuous protocols of up to 16 weeks before taking a break
AOD-9604 should be administered in a fasted state, with a minimum of 2 hours since the last meal. Morning dosing after an overnight fast is most common. Fasting is thought to maximize the lipolytic effect by avoiding insulin-mediated suppression of fat breakdown.
How to Use / Administration Methods
AOD-9604 is most commonly administered via subcutaneous injection, though clinical trials also explored oral dosing.
Subcutaneous injection procedure:
- Reconstitute the lyophilized powder with bacteriostatic water (see reconstitution section below)
- Draw the calculated dose using an insulin syringe
- Clean the injection site with an alcohol swab
- Pinch a skin fold at the abdomen (avoiding the 2-inch area around the navel), thigh, or upper arm
- Insert the needle at a 45 to 90 degree angle and inject slowly
- Withdraw the needle and do not rub the injection site
- Rotate injection sites to prevent localized tissue irritation
Timing: Administer first thing in the morning on an empty stomach. Wait at least 20 to 30 minutes before eating to avoid blunting the lipolytic response with an insulin spike.
Oral formulations: Clinical trials used oral dosing, and AOD-9604 has demonstrated approximately 40% oral bioavailability in animal studies. However, most community use involves subcutaneous injection, which delivers the peptide more reliably to systemic circulation. The peptide has a very short serum half-life commonly cited as approximately 4 minutes, though no peer-reviewed primary source has been identified for this figure and it may derive from marketing materials. Its downstream metabolic effects are thought to persist longer due to sustained activation of intracellular lipolytic pathways.
Results Timelines
AOD-9604 results are modest compared to approved anti-obesity medications. Timelines below are based on clinical trial data and community reports, not guaranteed outcomes.
Weeks 1 to 4: Minimal visible changes. Some users report subtle differences in how their body responds to exercise and diet. No significant weight loss is expected during this period based on available data.
Weeks 4 to 8: In the 12-week Phase IIa trial, treated subjects were on a trajectory that produced an average of 2.6 kg total weight loss by the end of the study. Any changes during this window are likely incremental and may be difficult to distinguish from normal fluctuations in body composition.
Weeks 8 to 12: The end of a standard cycle. The 12-week clinical trial showed an average difference of 1.8 kg between treatment and placebo groups. Users may notice modest reductions in abdominal adiposity if combined with consistent exercise and caloric control.
Beyond 12 weeks: The 24-week Phase IIb trial found no statistically significant difference between treatment and placebo groups, suggesting that any effects may plateau or diminish over longer durations. This is a significant limitation of the available evidence.
Research Evidence
The clinical development of AOD-9604 produced a mixed evidence base: strong preclinical results that did not translate into convincing human efficacy data.
Preclinical studies (late 1990s to early 2000s): Animal studies conducted at Monash University demonstrated that chronic administration of AOD-9604 to obese mice produced significant reductions in body weight gain, increased in vivo fat oxidation, and elevated plasma glycerol levels (a marker of lipolysis). These effects were mediated through the beta-3 adrenergic receptor pathway and were absent in beta-3 AR knockout animals.
Phase I/IIa trials (2001 to 2004): Early human studies established safety and tolerability. A 12-week randomized, double-blind, placebo-controlled trial of approximately 300 obese adults demonstrated that subjects receiving 1 mg/day oral AOD-9604 lost an average of 2.6 kg compared to 0.8 kg in the placebo group. These results were statistically significant and encouraged further development.
Phase IIb OPTIONS trial (2006 to 2007) — the definitive result: The larger and more rigorous 24-week Phase IIb trial enrolled 536 obese subjects randomized to receive 0.25, 0.5, or 1 mg/day oral AOD-9604 or placebo. The trial failed to meet its primary endpoint: none of the treatment arms demonstrated statistically significant weight loss compared to placebo. Metabolic Pharmaceuticals terminated development of AOD-9604 as an anti-obesity drug in March 2007. This Phase IIb failure is the most important clinical data point for AOD-9604 — a well-powered trial that directly contradicted the earlier, smaller Phase IIa result.
Safety review (2013): A comprehensive analysis published by Stier et al. pooled safety data from all six clinical trials (893 participants). AOD-9604 displayed a tolerability profile indistinguishable from placebo, with no serious adverse events attributed to the peptide, no impact on IGF-1 or glucose metabolism, and no detectable antibody formation.
Cartilage research (2015): A rabbit osteoarthritis model demonstrated that intra-articular AOD-9604, alone or combined with hyaluronic acid, improved cartilage regeneration and reduced joint degradation. These findings remain preclinical.
The honest assessment: AOD-9604's preclinical promise did not survive rigorous clinical testing. While the peptide appears safe, the evidence does not support it as an effective anti-obesity treatment at the doses studied.
Stacking
AOD-9604 is sometimes used alongside other peptides in body composition protocols. These combinations are experimental, off-label, and lack clinical validation.
With GH secretagogues (CJC-1295/Ipamorelin): The rationale is complementary mechanisms. AOD-9604 targets lipolysis directly via the beta-3 AR pathway, while GH secretagogues stimulate endogenous growth hormone release for broader metabolic effects. Users typically administer AOD-9604 in the morning fasted and GH secretagogues before bed to align with natural GH pulsatility.
With BPC-157: This combination targets both body composition and tissue repair. BPC-157's anti-inflammatory and healing properties may complement AOD-9604's emerging cartilage-supportive effects, particularly for individuals with joint issues alongside body composition goals.
With other fat-loss peptides (tesamorelin, 5-amino-1MQ): Some protocols layer multiple lipolytic agents. Tesamorelin, an FDA-approved GHRH analog for HIV-associated lipodystrophy, is sometimes combined with AOD-9604 for additive fat-reduction effects, though no clinical data supports this combination.
All stacking protocols carry unknown interaction risks and should only be considered under medical supervision.
Reconstitution, Storage & Prep
AOD-9604 is supplied as a lyophilized (freeze-dried) powder, typically in 2 mg or 5 mg vials. It must be reconstituted before use.
Reconstitution:
- Remove the plastic cap from the vial and wipe the rubber stopper with an alcohol swab
- Using a sterile syringe, draw the appropriate volume of bacteriostatic water (0.9% benzyl alcohol preserved)
- For a 5 mg vial, add 2.5 mL bacteriostatic water to achieve a concentration of 2 mg/mL (each 0.1 mL contains 200 mcg)
- For a 2 mg vial, add 1 mL bacteriostatic water to achieve a concentration of 2 mg/mL
- Inject the water slowly down the inside wall of the vial, not directly onto the powder
- Gently swirl or roll the vial until the powder is fully dissolved; do not shake
Storage:
- Unreconstituted powder: store at -20 degrees C (freezer) for long-term stability, or 2 to 8 degrees C (refrigerator) for shorter periods
- Reconstituted solution: refrigerate at 2 to 8 degrees C, protected from light, and use within 3 to 4 weeks
- Do not freeze reconstituted peptide solution
- Avoid repeated temperature fluctuations
Dosing calculation example: At a concentration of 2 mg/mL (2,000 mcg/mL), a 300 mcg dose requires 0.15 mL (15 units on a standard U-100 insulin syringe).
Side Effects
AOD-9604 demonstrated a favorable safety profile across six clinical trials, with adverse event rates that were not significantly different from placebo. The most commonly reported effects were mild and transient.
Commonly reported:
- Mild injection-site reactions (redness, swelling, or tenderness), typically resolving within 24 to 48 hours
- Occasional mild headaches
- Transient fatigue during the initial days of use
Not observed in clinical trials:
- No elevation of IGF-1 levels
- No impairment of glucose tolerance or carbohydrate metabolism
- No insulin resistance
- No anti-AOD-9604 antibody formation
- No fluid retention or joint pain
- No serious adverse events attributed to AOD-9604
Important limitations: The longest clinical trial duration was 24 weeks, and no data exist on effects beyond six months of use. The total clinical trial population was 893 participants, which is relatively small for detecting rare adverse events. Long-term safety data, particularly for subcutaneous injection routes not studied in the original trials, remain unavailable. The clinical trials used oral dosing; subcutaneous injection protocols common in community use have not undergone formal safety evaluation.
Legal Status / FDA
AOD-9604 occupies a complicated regulatory position across different jurisdictions.
United States: AOD-9604 is not FDA-approved as a drug for any indication. Its clinical development as an anti-obesity drug ended in 2007 after the Phase IIb trial failed. In December 2024, the FDA's Pharmacy Compounding Advisory Committee (PCAC) declined to include AOD-9604 on the Section 503A bulk drug substances list, effectively preventing compounding pharmacies from legally producing it for individual prescriptions. The FDA cited concerns about insufficient safety data for the injectable route and potential immunogenicity risks. AOD-9604 is currently available only as a research chemical labeled "not for human consumption."
Australia: AOD-9604 has a unique history in Australia as the country where it was developed. In the United States, it received GRAS (Generally Recognized As Safe) status from the FDA as a food ingredient, supported by safety data from the clinical trial program. A 2014 publication by Moré and Kenley characterized it as a "novel nutraceutical ingredient for improved metabolic health." It is not approved by the Therapeutic Goods Administration (TGA) as a therapeutic drug.
International: No regulatory agency worldwide has approved AOD-9604 as a drug for any therapeutic indication. Its availability varies by country, with most jurisdictions permitting sale for research purposes only.
Sports / WADA
AOD-9604 is prohibited in competitive sport. The World Anti-Doping Agency (WADA) classifies it under Section S.0 of the Prohibited List, which covers "any pharmacological substance with no current approval by any governmental regulatory health authority for human therapeutic use." As a growth hormone fragment, it also falls within the scope of Section S.2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics).
The substance is prohibited at all times, both in competition and out of competition. There was brief public confusion about AOD-9604's status in 2013 when an Australian Crime Commission report suggested the substance was not banned. WADA subsequently issued a formal statement clarifying that AOD-9604 was and remains prohibited.
Athletes in all WADA-compliant sports should assume AOD-9604 will result in an anti-doping rule violation. Even in sports not subject to WADA jurisdiction, athletes should verify the substance's status with their specific governing body before use.
Conclusion
AOD-9604 represents an intellectually compelling approach to obesity treatment, isolating the lipolytic domain of human growth hormone to target fat metabolism without the broader hormonal consequences. The preclinical science was sound, and the safety data from nearly 900 clinical trial participants were reassuring. However, the critical question for any therapeutic compound is efficacy, and AOD-9604 did not deliver. The Phase IIb trial's failure to demonstrate meaningful weight loss over 24 weeks ended its path to drug approval.
For individuals considering AOD-9604, the evidence should be weighed honestly. It appears to be well-tolerated with minimal side effects, but its fat-loss efficacy is unproven by the standards of modern clinical medicine. In an era where GLP-1 receptor agonists like semaglutide and tirzepatide deliver 15 to 25% body weight reductions in rigorous trials, AOD-9604's modest and inconsistent clinical results are difficult to justify as a primary weight-management strategy. See how AOD-9604 stacks up directly in the AOD-9604 vs semaglutide comparison. Those interested in peptide-based approaches to body composition should evaluate the full landscape of available options with a qualified healthcare provider.