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The Peptide Effect
phase 2Fat Loss

AOD-9604

Also known as: Anti-Obesity Drug 9604, hGH Fragment 177-191, Tyr-hGH Fragment 177-191

AOD-9604 is a synthetic modified fragment of human growth hormone (amino acids 177-191) originally developed as an anti-obesity therapeutic. It stimulates lipolysis and inhibits lipogenesis through the same mechanism as full-length hGH but without its growth-promoting, diabetogenic, or IGF-1-elevating effects. Despite promising early clinical data, its development as a pharmaceutical stalled after phase 2, and it is now primarily used in research and wellness contexts.

Key Facts

Mechanism
AOD-9604 mimics the lipolytic (fat-burning) domain of human growth hormone by interacting with the beta-3 adrenergic receptor pathway in adipose tissue. It stimulates lipolysis (fat breakdown) and inhibits lipogenesis (fat formation) without binding to growth hormone receptors. Unlike full-length hGH, it does not increase IGF-1 levels, does not affect blood glucose or insulin sensitivity, and does not promote cellular proliferation. The peptide also shows affinity for chondrocyte receptors, suggesting a role in cartilage repair that is under investigation.
Research Status
phase 2
Half-Life
~30 minutes
Molecular Formula
C₇₈H₁₂₃N₂₃O₂₃S₂
Primary Use
Fat Loss

Benefits

  • Stimulates fat breakdown without the growth-promoting effects of full hGHmoderate
  • Does not affect blood glucose, insulin levels, or IGF-1 (no diabetogenic risk)moderate
  • Potential cartilage repair and joint health benefits (chondrocyte stimulation)preliminary
  • Generally well-tolerated with minimal reported side effects in clinical studiesmoderate
  • No observed effect on appetite — targets fat metabolism directly rather than CNS appetite pathwayspreliminary

Dosage Protocols

RouteDosage RangeFrequencyNotes
Subcutaneous injection (fat loss protocol)250-300 mcgOnce dailyTypically administered in the morning on an empty stomach, 30 minutes before food. Inject into abdominal subcutaneous fat for localized effect. Common protocol duration is 12-20 weeks.
Subcutaneous injection (loading protocol)500 mcgOnce daily for 1-2 weeks, then reduce to 250 mcgSome practitioners use a higher initial dose before transitioning to maintenance. Limited clinical evidence for this approach.
Intra-articular injection (cartilage repair — investigational)200-400 mcg1-2× weeklyUsed experimentally for osteoarthritis and cartilage degeneration. Administered directly into the joint space by a medical professional. Not FDA-approved for this use.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Injection site reactions (redness, swelling, mild pain)common
  • Headacherare
  • Mild fluid retentionrare
  • Limited long-term safety data due to stalled clinical developmentserious

Frequently Asked Questions

What is the difference between AOD-9604 and hGH fragment 176-191?
AOD-9604 and hGH Fragment 176-191 are closely related but not identical. AOD-9604 is a modified version with an additional tyrosine residue at the N-terminus, making it Tyr-hGH(177-191). This modification improves stability and may enhance bioactivity. Some vendors use the terms interchangeably, but technically AOD-9604 refers specifically to the tyrosine-modified version that was used in clinical trials. Both are fragments of the C-terminal region of growth hormone responsible for its lipolytic activity.
Why did AOD-9604 clinical trials stall?
AOD-9604 completed phase 2 clinical trials in the early 2000s. While it demonstrated a favorable safety profile, the weight loss results were considered underwhelming by pharmaceutical standards — failing to meet the primary endpoint of statistically significant weight loss versus placebo in one key trial. The developing company (Metabolic Pharmaceuticals) faced financial difficulties, and the emergence of more effective anti-obesity drugs (GLP-1 agonists) further diminished commercial interest. This does not necessarily mean AOD-9604 is ineffective — it may have been underdosed or studied in suboptimal populations.
Does AOD-9604 actually work for fat loss?
Evidence is mixed. Preclinical studies in obese mice showed significant fat reduction. Phase 2 clinical trials showed modest fat loss improvements but results were not consistently statistically significant. Many anecdotal reports from research and wellness communities describe noticeable fat loss, particularly in stubborn areas. It is important to note that AOD-9604 is not FDA-approved for any indication, and its efficacy has not been conclusively demonstrated in large-scale human trials. This is not medical advice — consult a healthcare provider.
Is AOD-9604 legal and safe to use?
AOD-9604 is not FDA-approved for any medical use and is classified as a research peptide in the United States. It is not a controlled substance but exists in a regulatory gray area. It has been classified as a prohibited substance by WADA (World Anti-Doping Agency). In Australia, it has been approved as a food additive by the TGA. Clinical trial data suggests it is well-tolerated with minimal side effects, but long-term safety data is limited. Always consult with a qualified healthcare provider before using any research peptide.
Can AOD-9604 be combined with other peptides?
AOD-9604 is sometimes used alongside other peptides in research protocols. Common stacks include CJC-1295/Ipamorelin (for growth hormone release) and BPC-157 (for anti-inflammatory effects). Since AOD-9604 does not elevate IGF-1 or affect glucose metabolism, it is theoretically compatible with many compounds. However, there is no clinical trial data on peptide combinations, and combining research peptides increases the unpredictability of effects and side effects. Any peptide stacking should only be done under medical supervision.

References

  1. 1
    A synthetic fragment of human growth hormone (AOD9604) that reduces body fat in obese Zucker rats(2001)PubMed ↗
  2. 2
    AOD9604, a novel lipolytic peptide fragment of human growth hormone: safety, tolerability, and pharmacokinetics in healthy subjects(2003)PubMed ↗
  3. 3
    Metabolic effects of a synthetic lipolytic domain (AOD9604) of human growth hormone(2000)PubMed ↗
  4. 4
    The effect of the C-terminal fragment of human growth hormone on the proliferation and differentiation of chondrocytes(2005)PubMed ↗

Last updated: 2026-02-14