PeptidePeptideHGH fragmentAnti-obesity (failed)

AOD-9604

Also known as AOD9604 · HGH fragment analogue · Tyr-hGH 177-191

Written by enwyReviewed 15 Jul 20261 sources0 comments

AOD-9604 is a synthetic fragment of the C-terminus of human growth hormone (residues 176-191 plus a tyrosine) developed as an anti-obesity agent. It reached human clinical trials, which found it was well tolerated but produced no meaningful weight loss versus placebo. It is now marketed as a peptide for fat loss and joint repair despite the negative efficacy data.

01 Overview

AOD-9604 was engineered on the hypothesis that the fat-metabolising activity of growth hormone could be isolated in a short C-terminal fragment, giving lipolysis without GH's effects on IGF-1 or blood glucose. Metabolic Pharmaceuticals advanced it through Phase II obesity trials in the 2000s.

The pivotal human trials showed it was safe and did not raise IGF-1 or impair glucose tolerance, but it failed to beat placebo on weight loss at the tested doses, and development for obesity was discontinued. It later appeared as a compounded and research-chemical product for fat loss and, separately, is studied for cartilage/tendon applications. The FDA has declined to recognise it as a legitimate compounding ingredient.

02 Mechanism

Proposed to stimulate lipolysis and inhibit lipogenesis via a mechanism mimicking growth hormone's C-terminal fragment, reportedly without binding the GH receptor or raising IGF-1; the human relevance of this mechanism is unconfirmed by efficacy data.

03 Dosing

Tier	Dose	Route	Notes
Anecdotal	250–500 mcg/day	SubQ	Marketed dosing; trial doses were oral/higher. No dosing produces validated weight loss.

04 Effects

Effect	Magnitude	Evidence
Weight lossPhase II obesity trials did not show clinically meaningful weight loss over placebo.	No significant difference vs placebo in trials	Disputed
Claimed lipolysis / fat metabolismLipolytic activity demonstrated in preclinical models but not translated to human fat loss.	Seen in animal/adipocyte models	Preclinical

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Injection-site reactionsLocal irritation reported; overall the peptide was well tolerated in trials.	Mild	Common	Clinical
HeadacheMild headache reported during clinical testing.	Mild	Occasional in trials	Clinical

06 Legal status

United States

Not FDA-approved; rejected for compounding

FDA declined to list AOD-9604 as a bulk compounding substance; not approved as a drug. · as of Jan 2026

07 References

The effect of the AOD9604 peptide on weight loss in obese subjectsPhase II obesity trial report

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.