AOD-9604

AOD-9604 (Anti-Obesity Drug 9604) is a synthetic peptide built from 16 amino acids: the tail end of human growth hormone (hGH, amino acids 177–191) with an extra tyrosine added at the front ¹. It was designed to keep growth hormone's fat-mobilizing (lipolytic) action while dropping the blood-sugar-raising effects that full hGH carries ¹. In lab tests, unlike intact hGH, it does not bind the GH receptor and does not drive GH-receptor-mediated cell proliferation ³.

The compound was developed by Metabolic Pharmaceuticals in Australia, and its obesity program reached Phase IIa human testing by February 2002 ⁹. A 2003 trial report described favorable safety and tolerability ¹⁰, and a 2005 report said the orally active peptide "may aid weight reduction in obese subjects" ¹¹. Development never led to an approval. Since the mid-2000s, AOD-9604 shows up mainly in anti-doping literature and in reports of seized or confiscated vials in the USA, Denmark, and Belgium ¹.

Research interest today centers on fat loss and body recomposition, with joint support as a secondary area built on a single rabbit study ⁵. Human evidence remains limited to early-phase safety signals plus animal efficacy data, and reviews through 2026 consistently note that gray-market use of GH-axis peptides runs ahead of clinical evidence ⁷.

AOD-9604 reproduces the fat-breakdown (lipolytic) behavior of growth hormone without engaging the GH receptor itself ¹. In cells engineered to carry the hGH receptor, the peptide fails to compete with real hGH for binding and does not trigger receptor-driven cell proliferation ³. That supports a "pro-hormone" model of hGH: the hormone's fat-mobilizing activity is encoded in its C-terminal tail and works through signaling routes separate from the full-length hormone ³.

Key research findings:

• Lipolysis and fat oxidation: In obese (ob/ob) mice, 14 days of treatment reduced body-weight gain, increased fat oxidation, and raised plasma glycerol, a direct marker of fat breakdown ³. Obese Zucker rats given 500 mcg/kg/day orally for 19 days gained less than half the weight of untreated controls and showed increased adipose-tissue lipolytic activity ².
• No insulin penalty: The same mouse work found no rise in blood glucose and no suppression of insulin secretion, both of which intact hGH causes ³. In rats, 19 days of oral treatment left insulin sensitivity intact on a euglycemic clamp ².
• β3-adrenergic (β3-AR) pathway: Chronic treatment in obese mice restores repressed β3-AR RNA in fat tissue toward lean-animal levels. Mice missing β3-AR lose the chronic weight and lipolysis response, although a single dose still raises energy expenditure and fat oxidation in those knockouts ⁴. The working model is an acute, receptor-independent lipolytic push plus β3-AR upregulation that keeps fat tissue sensitive to ongoing fat mobilization ².

Parameter	Intact hGH	AOD-9604
hGH receptor binding	Yes	None 3
Lipolysis / fat oxidation	Increases	Increases 2
Hyperglycemia	Induces	Does not 3
Insulin secretion	Reduced	Unaffected 3
Insulin sensitivity	Impaired	Unaffected (clamp) 2
Receptor-mediated cell proliferation	Yes	No 3

The exact molecular target of the lipolytic effect is still unidentified ³. Early development positioned AOD-9604 as a drug that improves adipose-tissue function and fatty-acid metabolism rather than a centrally acting appetite suppressant ¹⁸. Any tissue-repair mechanism is also unresolved: an orthopaedic review groups AOD-9604 with GH-axis peptides said to "activate IGF-1 signaling and satellite-cell repair", but because the peptide does not bind the GH receptor, that pathway should not be assumed ³.

Human efficacy for AOD-9604 is limited to early-phase reports. A 2003 Phase II report described favorable safety and tolerability ¹⁰, and a 2005 report said the orally active peptide "may aid weight reduction in obese subjects" ¹¹. No published peer-reviewed human efficacy trial exists, and reviews through 2026 place AOD-9604 among GH-IGF1-axis peptides without regulatory-grade human evidence ⁷.

Animal data are more consistent:

• Weight and fat: Obese Zucker rats on 500 mcg/kg/day orally for 19 days gained more than 50% less weight than controls (15.8 g vs 35.6 g) with increased adipose-tissue lipolytic activity ². Obese and lean mice on 14 days of continuous treatment showed reduced weight gain, increased fat oxidation, and higher plasma glycerol ³.
• Metabolic neutrality: In mice, AOD-9604 produces no hyperglycemia and no reduction in insulin secretion, unlike intact hGH ³. In rats, insulin sensitivity stayed normal on a euglycemic clamp ².
• Joint effects (animal): Weekly ultrasound-guided intra-articular injection of 0.25 mg into a rabbit knee osteoarthritis model improved cartilage morphology and histopathology scores and shortened lameness versus saline. Adding 6 mg hyaluronic acid outperformed either agent alone ⁵.
• Not documented: There are no human performance, recovery, or recomposition trials; clinical reviews frame those effects as unproven ⁷. Human joint data are absent ⁵.

Strength of evidence, stated plainly: the core lipolytic findings come largely from one collaborating group (Ng, Heffernan, and colleagues) across rat and mouse models, internally consistent but not widely replicated ². The joint indication rests on a single rabbit study ⁵. Human data are thin ⁹.

Published human trial abstracts for AOD-9604 do not report dose, route, or regimen ⁹, so any human dosing pattern combines animal data with community research practice.

Established research doses:

Setting	Route	Dose	Frequency	Duration
Obese Zucker rat	Oral	500 mcg/kg	Daily	19 days 2
ob/ob and lean mice	Osmotic pump (IP)	Not stated	Continuous	14 days 3
Rabbit knee osteoarthritis	Intra-articular	0.25 mg (± 6 mg HA)	Weekly	4–7 weeks 5

Community research protocols for fat loss typically use 250–300 mcg subcutaneously once daily, often as a single fasted-morning dose, for 8–12 weeks. Some protocols split a 500 mcg day into 250 mcg morning and evening, and others reserve titration toward 500 mcg/day for heavier individuals or late-cycle plateaus. Joint-support protocols modeled on the rabbit data use 0.25 mg intra-articularly once weekly for 4–6 weeks.

Dose scaling: the only mg/kg figure in the literature is the 500 mcg/kg/day oral rat dose ². Linear extrapolation to humans would reach 27–50 mg/day across 55–100 kg bodyweights, which is unsupported; cross-species peptide scaling is unreliable, and community practice uses flat subcutaneous doses roughly 100-fold lower.

On timing: community protocols dose in the morning fasted state, matching peak endogenous lipolytic tone, and practitioners commonly time the dose 30–60 minutes before fasted cardio. In mice, single doses acutely increase energy expenditure and fat oxidation, including in β3-AR knockout animals ⁴. No human circadian or meal-interaction data exist.

AOD-9604 (Tyr-hGH177–191) is a 16-amino-acid C-terminal growth hormone fragment with a mass under 2 kDa ¹. Standard handling in research contexts:

• Diluent: Bacteriostatic water (0.9% benzyl alcohol) is the standard diluent; sterile water is acceptable for single-use preparations.
• Mixing: Inject diluent slowly against the vial wall and swirl gently; do not shake.
• Before mixing: Lyophilized (freeze-dried) vials store best at -20 °C long-term, with 2–8 °C acceptable short-term. Stability data show AOD-9604 holds within 15% variation at -20 °C for at least 2 months in blood matrices, and dried samples stay detectable through the entire study even without refrigeration ¹².
• After mixing: Refrigerate at 2–8 °C and use within 14–28 days; avoid repeated freeze–thaw cycles.
• Stability note: AOD-9604 degrades extensively within one week in serum and plasma at 4 °C and 22 °C ¹². That instability reflects enzymes in biological fluids, not the peptide sitting in bacteriostatic water, but it makes gentle handling and refrigeration the norm.

Product integrity deserves attention in the research setting: AOD-9604 has been identified in confiscated gray-market vials in the USA ¹, Denmark ¹⁴, and Belgium ¹⁶, and unregulated supply composition and dose accuracy are unverified. Use the reconstitution calculator below to work out diluent volumes and dose concentrations for a given vial size.

No dedicated human drug-interaction studies exist for AOD-9604. The compound reached Phase II obesity testing ⁹, but interaction surveillance was not systematic, so guidance below rests on animal and in-vitro pharmacology plus mechanistic inference.

Agent	Risk	Notes
Exogenous hGH	Low–moderate, additive	AOD-9604 does not compete for GH-receptor binding 3; combined lipolysis may burden glucose control
Insulin, sulfonylureas	Low (animal)	No hyperglycemia or insulin suppression in mice 3; clamp insulin sensitivity preserved in rats 2
Corticosteroids	Theoretical	Glucocorticoids oppose lipolysis and may blunt effect
Non-selective beta-blockers	Theoretical	May reduce the fat-oxidation response given the β3-AR role 4
Beta-2/3 agonists	Theoretical, additive	Additive adrenergic lipolysis; watch heart rate and blood pressure
Thyroid hormone	Theoretical, additive	Combined metabolic-rate elevation
Hyaluronic acid (intra-articular)	Positive (animal)	AOD-9604 0.25 mg plus HA 6 mg outperformed either alone in a rabbit OA model 5
Anti-doping tests	Neutral	Does not influence the WADA hGH isoform immunoassay 15

Peptide combinations seen in the research community:

• GLP-1 peptides (semaglutide, tirzepatide): the most common community fat-loss stack. Independent mechanisms, satiety versus peripheral lipolysis, so hypoglycemia risk is low unless insulin or secretagogues are also involved. Additive nausea is possible when both are started at once, so community protocols overlap low-dose titration phases.
• Growth hormone secretagogues (ipamorelin, CJC-1295, sermorelin): biologically plausible for recomposition, since AOD-9604's effects do not require IGF-1 generation through the GH receptor ³. The secretagogue side carries class-level prolactin, cortisol, and dysglycemia risks ⁷, so protocols typically monitor fasting glucose and often alternate or stagger injection timing.
• hGH or IGF-1 LR3: additive load on the glucose and lipid axis; class-level dysglycemia concerns apply ⁷.
• Healing peptides (BPC-157, TB-500, GHK-Cu): no shared mechanism, and joint-rehab combinations are consistent with the animal AOD-9604 plus HA benefit ⁵.

Among supplements, caffeine combinations carry low-to-moderate theoretical additive risk, yohimbine moderate, and ephedra or synephrine high; the latter two are typically avoided in combination protocols. One storage rule repeats across practice: do not pre-mix AOD-9604 with other peptides in liquid for multi-day storage, given its week-long degradation in biological fluids at 4–22 °C ¹². Reconstitute separately and use promptly.

Human data on cycling AOD-9604 do not exist in randomized form. Community and practitioner protocols converge on 250–500 mcg/day subcutaneously, typically a single fasted-morning dose, with some protocols splitting 250 mcg morning and evening.

Common patterns:

• Standard: 8–12 weeks on, 4–6 weeks off.
• Extended: 12–20 weeks on, 6–8 weeks off, used by some practitioners given the peptide's clean metabolic profile in animals.
• Intermittent: a 5-days-on, 2-days-off variant with no separate washout; unvalidated.

Preclinical timing anchors the on-phase length: animal effects appear within 14–19 days of continuous dosing ², and the rabbit intra-articular benefit was read out at week 8 ⁵. Off-phases shorter than about 4 weeks leave little room for reassessment.

Does AOD-9604 actually need cycling? The usual secretagogue logic does not transfer cleanly: AOD-9604 does not bind the GH receptor ³, so there is no receptor "reset" problem of the kind that drives GHRP cycles with their prolactin, cortisol, and dysglycemia class effects ⁷. Cycling instead rests on three grounds: possible lipolytic pathway adaptation as chronic β3-AR upregulation plateaus ⁴; long-term human safety uncertainty ⁷; and practical factors like cost, supply consistency, and product degradation in liquid ¹². No tachyphylaxis, desensitization, or rebound signal appears anywhere in the literature.

Reasons protocols pause a cycle: fat loss stalling for 3 or more weeks at an unchanged dose, since animal responses appear within 14–19 days ²); accumulating side effects from the broader GH-axis class profile (fluid retention, myalgia, injection-site reactions) ⁷; product-integrity concerns from degraded or mishandled vials ¹²; and competition windows, because AOD-9604 is WADA-prohibited ¹.

Stacking design follows from one fact: AOD-9604 raises fat breakdown without touching the GH receptor ³, so it adds lipolysis without adding secretagogue-style endocrine load. Commonly discussed combinations:

• AOD-9604 + GLP-1 peptides (semaglutide, tirzepatide, liraglutide): the most common community fat-loss stack. Independent mechanisms, central satiety plus peripheral lipolysis, with no shared receptor. Low hypoglycemia risk unless insulin or secretagogues are in the regimen. Community protocols overlap low-dose titration phases to avoid additive nausea.
• AOD-9604 + GH secretagogues (ipamorelin, CJC-1295, sermorelin, tesamorelin): plausible for recomposition. AOD-9604's effects do not require IGF-1 generation through the GH receptor ³, while the secretagogue side carries prolactin, cortisol, and dysglycemia class risks ⁷. Protocols generally monitor fasting glucose and often alternate or stagger the two injections.
• AOD-9604 + hGH or IGF-1 LR3: an additive load on the glucose and lipid axis; class-level dysglycemia concern ⁷. Usually avoided where fasting glucose is already impaired.
• AOD-9604 + healing peptides (BPC-157, TB-500, GHK-Cu): no shared mechanism, and joint-rehab stacking is consistent with the rabbit data showing AOD-9604 plus hyaluronic acid beating either agent alone ⁵.
• AOD-9604 + hyaluronic acid (intra-articular): the one combination with direct animal evidence, outperforming either agent alone on cartilage scores and lameness in the rabbit knee model ⁵.

Handling rule from practitioner practice, grounded in stability data: AOD-9604 degrades within about a week in biological fluids at 4–22 °C ¹², so liquid multi-day premixes with other peptides are avoided; each peptide is reconstituted separately and used promptly.

AOD-9604 has no drug approval in any jurisdiction. The legitimate development program stalled after early-phase work: Phase IIa obesity testing was underway by February 2002 ⁹, a 2003 report described favorable safety and tolerability ¹⁰, and the compound still appeared among investigational anti-obesity agents in reviews up through 2012 ¹⁹. No FDA, EMA, MHRA, or TGA marketing authorization was ever documented ¹⁸. It is not a controlled substance and is absent from the FDA 503A bulk drug substances list, yet it circulates through unregulated gray-market channels as an injectable research peptide ⁷.

Enforcement history is real: AOD-9604 has been identified in confiscated vials in the USA ¹, among peptide and protein doping compounds confiscated in Denmark between 2007 and 2013 ¹⁴, and in seized pharmaceutical preparations characterized in Belgium ¹⁶. Unverified composition and dose accuracy are documented risks of that supply chain ¹⁶.

In sport, AOD-9604 sits on the WADA Prohibited List under S2 (peptide hormones, growth factors, related substances, and mimetics) as a growth hormone fragment, prohibited at all times, in and out of competition. Detection is mature, which limits practical use in tested sport:

• Urine solid-phase extraction with a limit of detection of 50 pg/mL ¹.
• Direct urine injection with ion-mobility mass spectrometry covering the peptide at 50–500 pg/mL ⁶.
• A stable serum/urine metabolite (CRSVEGSCG) that extends the detection window beyond the parent peptide ¹.
• Dried-blood-spot workflows that detect the peptide and stay stable long-term without refrigeration ¹².

AOD-9604 does not interfere with the WADA hGH isoform immunoassay, so it neither masks nor confounds growth hormone testing ¹⁵.

Human safety data for AOD-9604 are early-phase. A 2003 Phase II report described favorable safety and tolerability ¹⁰, but no published human trial gives quantitative adverse-event rates. Reviews through 2026 repeatedly stress that rigorous long-term safety data for unapproved GH-axis peptides are scarce ⁷.

The preclinical metabolic profile is the main safety argument:

• No hyperglycemia and no suppression of insulin secretion in obese mice, unlike intact hGH ³.
• Preserved insulin sensitivity on euglycemic clamp in Zucker rats ².
• No competition for the GH receptor and no GH-receptor-mediated cell proliferation in vitro ³.

That said, GH-IGF1-axis peptides as a class carry documented effects: injection-site reactions, fluid retention, muscle and joint aches, appetite changes, dysglycemia, and prolactin or cortisol elevations ⁷. These reports derive largely from secretagogue-class compounds, and AOD-9604's lack of GH-receptor binding makes several of them mechanistically less likely, though not excluded ³. Community research reports at 250–500 mcg/day are modest: transient redness or bruising at the injection site is most common, with occasional mild headache or nausea in the first days that usually resolves.

Open questions worth weighing:

• Long-term and cumulative safety is unknown; human exposure in clinical development was short-duration only ⁹.
• Mitogenic risk: class-level concerns that GH-axis peptides might promote cell growth are biologically plausible but unproven ⁸. AOD-9604 shows no direct proliferative signaling in vitro ³, but that does not substitute for long-term data.
• Product risk: the peptide degrades extensively within a week in biological fluids at 4–22 °C ¹², and confiscated-vial analyses confirm gray-market quality failures ¹⁴. Reactions observed in the field may reflect excipients or mislabeled compounds rather than AOD-9604 itself.

In research practice, contraindications follow the class profile: active malignancy or a cancer history within 5 years, known hypersensitivity, and pregnancy or breastfeeding, for which no data exist ⁷. Diabetes and impaired glucose tolerance are handled with monitoring rather than outright avoidance, since the animal signal favors preserved insulin sensitivity ². Practitioners generally check fasting glucose and HbA1c at baseline and roughly every 3 months; IGF-1 monitoring is low-yield because AOD-9604 does not signal through the GH receptor ³.