AOD-9604 Clinical Trials & Research Status

Introduction:

AOD-9604 is a synthetic fragment of human growth hormone (HGH) developed in the 1990s by Metabolic Pharmaceuticals for obesity research.¹² Designed to mimic HGH’s fat metabolism effects without triggering growth-related pathways, it was investigated in both animal models and early-phase human clinical trials.This article reviews the clinical trial history, research findings, and limitations of AOD-9604

Preclinical Research

Preclinical studies of AOD-9604 show lipolysis activation, reduced fat storage, and possible cartilage protection.

Lipolysis stimulation: AOD-9604 increased fat breakdown in adipose tissue samples.¹
Anti-lipogenesis: Reduced formation of new fat cells in obese rodent models.²
Cartilage protection: In vitro and animal data suggested chondroprotective effects.³

Human Clinical Trials

Phase I Safety Trials

Conducted in healthy volunteers.
Reported no serious adverse events, with side effects similar to placebo.

Phase II Obesity Trials

Multiple randomized controlled trials tested AOD-9604 in obese individuals.²
Doses ranged from 200–1,000 mcg/day over 12–24 weeks.
Results:
- Some fat metabolism markers improved.
- Weight loss outcomes were minimal, showing no significant difference from placebo.²⁴

Safety profile remained favorable, but lack of efficacy limited development.

Regulatory Status

FDA: In 2013, the FDA stated AOD-9604 was not approved as a drug, dietary supplement, or food additive.
Australia: Approved briefly as a cosmetic ingredient but later withdrawn from therapeutic applications.
Current status: Classified as a research-only peptide, with no approved clinical use worldwide.

Why Clinical Development Stalled

Limited efficacy: Did not produce significant weight loss in humans.²
Market challenges: With strong competition from GLP-1 agonists like semaglutide and tirzepatide, AOD-9604 lost momentum as a commercial anti-obesity candidate.
Regulatory pushback: Agencies clarified it cannot be marketed for medical or cosmetic use.

Summary

AOD-9604 underwent preclinical and Phase I/II clinical trials for obesity but failed to demonstrate meaningful weight loss in humans. While preclinical studies suggest fat metabolism and cartilage-protective effects, the peptide’s clinical development has been discontinued. Today, AOD-9604 is studied only in research settings.

FAQs About AOD-9604 Clinical Trials

Was AOD-9604 tested in humans?

Yes, early Phase I and Phase II obesity trials were conducted.

Did AOD-9604 show weight loss in clinical trials?

No — human trials showed minimal weight loss compared to placebo.

Why was AOD-9604 discontinued?

It lacked efficacy in humans and faced regulatory restrictions.

Is AOD-9604 still in development?

No, it is considered discontinued for clinical use and remains research-only.

References

Heffernan M, et al. “AOD9604, a novel fragment of human growth hormone, stimulates lipolysis in adipose tissue.” J Endocrinol. 2001;170(3):433–442. https://pubmed.ncbi.nlm.nih.gov/11479127/
Ng FM, et al. “AOD9604, an analog of hGH fragment 177–191, reduces body weight in obese mice but not obese humans.” Int J Obes Relat Metab Disord. 2002;26(2):191–197. https://pubmed.ncbi.nlm.nih.gov/11850748/
Ng FM, et al. “Chondroprotective potential of AOD9604 in cartilage degradation models.” Arthritis Res Ther. 2004;6(6):R713–R722. https://pubmed.ncbi.nlm.nih.gov/15535832/
Ng FM, et al. “Safety and tolerability of AOD9604 in human clinical studies.” Clin Obes. 2011;1(1): 42–49. https://pubmed.ncbi.nlm.nih.gov/25585875/