Summary

AOD-9604 is a synthetic 15-amino-acid peptide based on the C-terminal fragment (residues 177–191) of human growth hormone. Developed in the late 1990s by Metabolic Pharmaceuticals, it was designed to replicate the fat-burning (lipolytic) effects of hGH without its effects on blood glucose, tissue growth, or IGF-1. It reached Phase II human clinical trials, making it one of the more clinically researched peptides in the fat-loss category.

Overview

AOD-9604 is a synthetic peptide analogue of the C-terminal fragment of human growth hormone (hGH), specifically amino acids 177–191. It was developed by Metabolic Pharmaceuticals (Australia) in the late 1990s as a targeted approach to fat metabolism without the broader systemic effects of full-length growth hormone. The peptide mimics the lipolytic (fat-releasing) action of hGH while apparently avoiding its effects on blood glucose, tissue growth, and IGF-1 production.

The rationale is elegant: the fat-burning properties of hGH appear to be localised to a specific region of the hormone. By isolating and modifying that fragment, researchers aimed to achieve fat loss without the side effects associated with full hGH administration (such as insulin resistance, tissue growth, or organomegaly).

Research Summary

Human Clinical Trials

AOD-9604 is unusual among research peptides in that it has progressed through multiple phases of human clinical trials.

  • Phase II trials: A series of randomised, double-blind, placebo-controlled trials were conducted in the 2000s. The largest reported trial involved approximately 500 obese subjects over 12 weeks, showing statistically significant weight loss compared to placebo at daily doses of 1 mg and 5 mg, though the magnitude of weight loss was modest (Stier et al., 2006).

  • Lipolysis mechanism: In vitro and animal studies confirmed that AOD-9604 stimulates lipolysis (fat breakdown) and inhibits lipogenesis (fat formation) in adipose tissue. A 2001 study by Ng et al. demonstrated that the hGH 177–191 fragment stimulated lipolysis in isolated adipocytes without affecting glucose metabolism (Ng et al., 2001).

  • Safety profile: The clinical trial programme reported that AOD-9604 was generally well-tolerated, with no significant effects on glucose tolerance, insulin sensitivity, or IGF-1 levels — a notable contrast with full-length growth hormone. However, the magnitude of weight loss achieved did not meet the efficacy thresholds required for regulatory approval as an anti-obesity drug, and development was discontinued.

Regulatory History

AOD-9604 received Investigational New Drug (IND) status from the US FDA but was not ultimately approved as a medicine. It was never submitted to or approved by the MHRA or EMA as a licensed pharmaceutical.

Limitations

While the human trial data is more extensive than for many research peptides, the trials were conducted over a decade ago and results have not been replicated in more recent studies. The modest effect size means its practical utility as a fat-loss agent remains debated.

Commonly Discussed Protocols

Note: The following describes protocols commonly discussed in research communities. This is not medical advice. AOD-9604 is sold for research use only.

  • Subcutaneous injection: Commonly discussed doses range from 250–500 micrograms (mcg) per day, typically administered once daily.
  • Cycle length: Protocols of 4–12 weeks are frequently mentioned, with a minimum 4-week break between cycles.
  • Timing: Some researchers prefer morning administration to align with natural circadian hormone patterns.
  • Route: Subcutaneous injection into abdominal fat is the most commonly discussed method.

Stacking

AOD-9604 is sometimes discussed in combination with other compounds:

  • CJC-1295 / Ipamorelin: Some researchers combine AOD-9604 with growth hormone secretagogues, theorising that increased endogenous GH may complement AOD-9604's lipolytic action. No published studies validate this combination.
  • Fragment 176-191 (hGH fragment): This is a closely related peptide; some protocols discuss alternating between the two, though there is no clinical evidence supporting this approach.

Storage & Reconstitution

  • Lyophilised powder: Store at -20°C for long-term storage, or 2–8°C for short-term use. Protect from light.
  • Reconstitution: Reconstitute with bacteriostatic water. Gently swirl — do not shake.
  • Reconstituted solution: Store at 2–8°C and use within 28–30 days.

Blood Work

While AOD-9604 was designed to avoid the metabolic effects of full hGH, researchers monitoring its use may consider:

  • Lipid panel — total cholesterol, LDL, HDL, triglycerides to monitor fat metabolism effects
  • Fasting glucose and HbA1c — to monitor glucose metabolism, even though trials suggested minimal impact
  • Insulin levels — to verify the peptide is not affecting insulin sensitivity
  • IGF-1 — to confirm the peptide is not stimulating GH-pathway growth markers (trials suggested it should not)

UK Legal Status

AOD-9604 is not a licensed medicine in the UK. It is legal to purchase and possess for research purposes. It is not listed under the Misuse of Drugs Act and is not a controlled substance. The MHRA has not approved AOD-9604 as a medicinal product. Though it previously held IND status in the US (FDA), this was for clinical investigation only and does not constitute approval for human use.

References

  1. Stier H, Vos W, Van Oudtshoorn-Tomlinson E. "AOD9604: An Anti-Obesity Drug Candidate." Drug Development Research. 2006; 67(8): 734-744. DOI: 10.1002/ddr.20135
  2. Ng FM, et al. "Growth Hormone Fragment (hGH 177-191) Enhances Lipolysis and Inhibits Lipogenesis." Endocrinology. 2001. DOI: 10.1210/endo.142.1.7927
  3. Metabolic Pharmaceuticals Limited. "AOD9604 Clinical Development Summary." Company announcement, 2007.
  4. Cox HD, et al. "Detection of AOD-9604 and its metabolites in plasma by liquid chromatography-mass spectrometry." Drug Testing and Analysis. 2015.

References

  1. Stier H, Vos W, Van Oudtshoorn-Tomlinson E. "AOD9604: An Anti-Obesity Drug Candidate." Drug Development Research. 2006; 67(8): 734-744. DOI: 10.1002/ddr.20135
  2. Ng FM, et al. "Growth Hormone Fragment (hGH 177-191) Enhances Lipolysis and Inhibits Lipogenesis." Endocrinology. 2001. DOI: 10.1210/endo.142.1.7927
  3. Metabolic Pharmaceuticals Limited. "AOD9604 Clinical Development Summary." Company announcement, 2007.
  4. Cox HD, et al. "Detection of AOD-9604 and its metabolites in plasma by liquid chromatography-mass spectrometry." Drug Testing and Analysis. 2015.