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GH Fragment / Lipolytic Peptide

AOD-9604

Also known as: Anti-Obesity Drug 9604, hGH Fragment 176-191 analog

A modified 16-amino-acid fragment of human growth hormone's C-terminus, engineered to isolate its fat-metabolizing (lipolytic) activity from its growth-promoting effects. The most clinically developed 'GH fragment' compound, though it did not reach approval.

Educational content, not advice. Compiled from information publicly available on the internet; it may contain inaccuracies and was not written or reviewed by medical professionals. Use it as a starting point for your own research, verify against primary sources, and see our full disclaimer.

Overview

AOD-9604 is a synthetic, modified version of amino acids 176-191 at the C-terminus of human growth hormone (hGH) — the region researchers identified as responsible for hGH's fat-metabolizing effects, separate from the growth-promoting effects mediated by other parts of the hormone. It was developed by Metabolic Pharmaceuticals (Australia) specifically to isolate that lipolytic activity as a standalone, orally available compound.

Proposed Mechanism of Action

AOD-9604 is believed to activate beta-3 adrenergic receptors concentrated in adipose tissue, upregulating hormone-sensitive lipase and promoting breakdown of stored triglycerides — without activating the growth hormone receptor pathway responsible for hGH's other systemic effects.

Research Context

The cited study is a preclinical animal model (obese Zucker rats), showing reduced weight gain and increased lipolytic activity with oral dosing, and — notably — no negative effect on insulin sensitivity, in contrast to what's seen with full-length hGH. Beyond this animal data, AOD-9604 is one of the few compounds discussed on this site to have gone through actual human Phase II clinical trials (multiple published reports describe placebo-controlled trials with hundreds of obese adult subjects). However, according to multiple industry and news sources, later Phase IIb trials failed to meet their primary efficacy endpoint for weight loss, and pharmaceutical development was discontinued around 2007. We were not able to independently verify a PubMed-indexed citation for the specific human trial results at the time of writing — treat human-efficacy claims about AOD-9604 with particular caution until you can trace them to a peer-reviewed publication rather than a company press release.

Limitations of the Current Evidence

  • The only citation we've independently verified here is an animal (rat) study; human trial data exists in the public record (industry reports, conference abstracts) but we could not confirm it via a peer-reviewed, PubMed-indexed publication.
  • The compound's own development history — advancing to Phase IIb before failing its primary endpoint — is itself relevant context: this is not simply an untested compound, it's one that was tested at scale and didn't clear the bar for approval.

Research-Setting Dosing (as reported in literature)

RouteRange (as reported)FrequencyNotes
Oral0.5–0.5 mg/kgDaily for 19 daysObese Zucker rat model (Ng et al., 2000); reduced weight gain by over 50% versus control, with increased adipose lipolytic activity and no adverse effect on insulin sensitivity in this model.

Figures above are extracted directly from the cited preclinical/research literature. They describe what researchers administered to study subjects (frequently animal models) — they are not human dosing recommendations and are not medical advice.

Cited Studies

  • Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone

    Ng FM, Sun J, Sharma L, Libinaka R, Jiang WJ, Gianello R · Hormone Research · 2000

    Animal study (obese Zucker rat)View source →

Last updated August 1, 2026