AOD-9604: What the Research Shows

AOD-9604 began as one of the neater ideas in obesity research: isolate the small piece of growth hormone that seemed to burn fat, and leave the rest of the hormone behind. It made it all the way to a large phase 2b trial, and it failed. What remains is an unusually well-documented research peptide, and a clear lesson in why animal results don’t guarantee human ones.

This guide covers what AOD-9604 is, what the trials found, how it relates to HGH Fragment 176–191, and what to check before ordering it in Canada.

The idea behind AOD-9604

Growth hormone does many things at once: it promotes growth through IGF-1, raises blood sugar and also breaks down stored fat. Researchers at Monash University in Melbourne, led by Frank Ng, wanted to separate the fat-burning effect from the rest. In 1993 they reported that a synthetic version of growth hormone’s C-terminal region, residues 177 to 191, reproduced the hormone’s anti-fat-storage activity in rat fat tissue.

AOD-9604 adds a tyrosine to the front of that fragment. In obese mice it reduced weight gain and fat mass. A 2001 study found it had no such effect in mice lacking beta-3 adrenergic receptors, pointing to that pathway as a key part of the mechanism.

What the human trials found

1. 2001–2006Metabolic Pharmaceuticals runs six clinical trials enrolling roughly 900 participants. Safety and tolerability look acceptable.
2. Mid-2000sA 12-week phase 2 study reports modest weight loss compared with placebo, and the company plans a pivotal trial.
3. 2007A 24-week phase 2b trial in 536 people fails to show significant weight loss versus placebo, and the obesity program is terminated.

That sequence is common in obesity research: a small, short study shows a signal, and a larger, longer one does not. AOD-9604 never reached phase 3 and has never been approved as a medicine anywhere.

Why promising animal data failed

Nobody can say for certain, but one explanation fits a broader pattern. Beta-3 adrenergic receptors play a much larger role in rodent fat tissue than in human fat, which is one reason many compounds that burn fat well in mice have disappointed in people. If AOD-9604’s effect depends heavily on that pathway, as the knockout-mouse study suggested, a strong mouse result could easily shrink to nothing in humans.

AOD-9604 vs HGH Fragment 176–191

HGH Fragment 176–191 is a closely related research peptide: the last 16 residues of growth hormone, starting at phenylalanine 176. AOD-9604 replaces that first phenylalanine with tyrosine. Naming varies between suppliers, so the safest check is the sequence and mass on the certificate of analysis rather than the name on the vial.

AOD-9604Tyr-hGH(177–191)View product and COA HGH Fragment 176–191The closely related fragmentView product and COA MOTS-cMitochondrial metabolic peptideView product and COA TesamorelinGHRH analogue with trial dataView product and COA

For a metabolic peptide with a very different research story, see MOTS-c, SS-31 and humanin. For a growth hormone-axis peptide with positive phase 3 data in a specific population, see tesamorelin.

Sourcing AOD-9604 in Canada

Before ordering AOD-9604 from any supplier, check that:

• The sequence starts with tyrosine. That is what separates AOD-9604 from HGH Fragment 176–191.
• The disulfide is accounted for. Forming the bridge between the two cysteines removes two hydrogen atoms, so the oxidized peptide is 2 g/mol lighter than the reduced form. A good mass result reflects the expected form. See HPLC vs mass spectrometry.
• The COA matches your lot. How to read a certificate of analysis explains what to look for.
• Storage is cold, dry and dark. See our peptide storage guide.

Frequently asked questions