Metabolic · Research compound

What is AOD-9604?

Q: What is AOD-9604?

AOD-9604 is a synthetic peptide based on the C-terminal lipolytic fragment of human growth hormone (residues 176-191). In animals it stimulated fat breakdown and weight loss without growth hormone's effects on growth or blood sugar. But that animal fat-loss result was not reproduced in human obesity development, and it never became an approved weight-loss drug.

A synthetic fragment of growth hormone — the 176-191 "lipolytic domain" — studied as a fat-burning peptide that works in animals but didn't reproduce that result in human trials.

Reviewed against primary literature Last updated Jun 2026 For research use only

tuned AOD-9604 research vial, ≥99% purity

Purity · UPLC≥99%

In short

AOD-9604 is a small synthetic peptide based on the C-terminal "lipolytic" fragment of human growth hormone (residues 176-191).[1] Its appeal is selectivity: in animals it stimulated fat breakdown and weight loss without growth hormone's effects on growth or blood sugar.[2][3] The honest catch is the part most pages skip: that striking animal fat-loss result was not reproduced in human obesity development, and AOD-9604 never became an approved weight-loss drug.[4]

01 — What it is

What is AOD-9604, exactly?

AOD-9604 is a synthetic peptide engineered from the last part of the growth-hormone molecule — amino acids 176-191, the region linked to GH's fat-metabolising activity — with a small modification (an added tyrosine) for stability.[1]

The idea behind it was elegant: growth hormone has many actions, only some of which involve burning fat. AOD-9604 (also called the hGH fragment 176-191) isolates the lipolytic domain in the hope of getting the fat effect on its own.[1] It was developed by Metabolic Pharmaceuticals as an investigational anti-obesity compound.[4]

Is AOD-9604 a peptide, and what is the hGH fragment 176-191?

Yes — AOD-9604 is a short peptide, and "hGH fragment 176-191" refers to the same molecule. It is supplied as a lyophilized powder and studied as an injectable. The "for men" framing that appears in searches reflects its popularity in male fat-loss circles, but the underlying pharmacology is not sex-specific and the human evidence is limited for anyone.

02 — How it works

What does AOD-9604 do, and how does it work?

In the laboratory, AOD-9604 does two complementary things to fat tissue: it stimulates lipolysis (the breakdown of stored fat) and inhibits lipogenesis (the formation of new fat), increasing fat oxidation.[2][3]

The lipolytic mechanism — fat effect without the GH effects

The distinctive claim, supported by the animal work, is selectivity: AOD-9604 reproduced growth hormone's fat-reducing action without raising IGF-1 or impairing insulin sensitivity the way full GH can, and the effect did not appear to depend on the classic GH receptor in the same way.[3] In obese mice, chronic treatment increased fat oxidation and reduced body weight.[2] That clean, fat-specific profile in animals is the entire basis of AOD-9604's reputation — and the reason the gap to human results matters so much.

03 — Benefits & the evidence gap

AOD-9604 benefits

The AOD-9604 benefits discussed in research all flow from that animal lipolytic profile — but they must be read against the animal-to-human gap, which is the defining feature of this compound:

Fat breakdown & oxidation — demonstrated in cells and animals.[2][3]
Weight loss — shown in obese mice with chronic treatment.[2]
No GH/IGF-1 or blood-sugar penalty — the selectivity claim, from the animal work.[3]
Later non-obesity interest — AOD-9604 has been explored in connective-tissue/musculoskeletal contexts, separate from the obesity story.

Why the human results matter most

Here is the honesty other pages skip: AOD-9604 was taken into human obesity development, but the dramatic fat-loss seen in animals was not reproduced as an approved human therapy, and the obesity program did not yield a marketed drug.[4] So the benefits are best described as strong in animals, unproven in humans. The popular "fat-loss peptide" framing rests on the animal data and anecdote, not on controlled human efficacy, and AOD-9604 is not an approved treatment for obesity or weight loss.

This animal-to-human gap is worth dwelling on, because it is the single most useful fact about AOD-9604 and the one most often left out. Promising rodent metabolic results frequently fail to scale to humans — differences in dose, metabolism and the complexity of human body-weight regulation all intervene — and AOD-9604 is a textbook example: a clean, selective fat effect in mice that did not translate into an approved human weight-loss therapy.[2][4] Reading the compound honestly means holding both halves at once — the genuine, well-characterised mechanism, and the absence of human efficacy behind the marketing.

04 — Results

AOD-9604 before and after

"AOD-9604 before and after" reports shared online are anecdotal — self-reported changes in body fat, usually alongside diet and training, with unverified material. They are not controlled data and cannot establish that the peptide caused the change.

What documented results actually exist

The documented "before and after" for AOD-9604 is the animal result: increased fat oxidation and reduced body weight in obese mice over chronic treatment.[2] No controlled human trial established a comparable body-composition outcome, which is exactly why human "results" should be read cautiously. The mechanism is real in the lab; the human transformation claims run ahead of the evidence.

05 — Side effects & safety

AOD-9604 side effects

Because AOD-9604 lacks the broad growth-hormone actions, its theoretical side-effect profile is comparatively narrow — the animal and early human work did not show the IGF-1 elevation or insulin-sensitivity penalty associated with full GH.[3] Reported considerations are mostly the practical ones for any injectable peptide (injection-site reactions) plus the general uncertainty of a compound without long-term human safety data.

What "favourable in animals" does and doesn't mean

A clean profile in animal studies is encouraging but is not the same as established human safety. AOD-9604 has not completed the long-term human safety evaluation an approved medicine carries, and the research-chemical material is not a pharmaceutical product. As with any research peptide, the most controllable real-world risk is material quality — a batch-specific Certificate of Analysis (UPLC purity, identity, endotoxin) does more for safety than any dosing convention.

Type

hGH fragment

Region

176-191

Action

Lipolytic

Approved?

06 — Dosage

AOD-9604 dosage

There is no established human dose for AOD-9604. It is not an approved medicine, so there is no regulated dosage, and the per-day figures, charts and reconstitution conventions circulated in fat-loss communities are unverified.[4] The dosing used in the animal research was specific to those experimental models.[2]

This page does not provide dosing amounts, syringe measurements, reconstitution instructions, or administration guidance — including "maximum daily" figures or subcutaneous-shot schedules. Any AOD-9604 dosage figure or calculator found online should be treated as an unverified community convention rather than clinical guidance.

07 — Stacks

AOD-9604 vs and with tesamorelin

A common comparison is "AOD-9604 vs tesamorelin," since both are growth-hormone-related and discussed for fat. They are quite different: tesamorelin is a GHRH analog that raises the whole GH/IGF-1 axis and has randomized-trial evidence for reducing visceral fat in a specific approved indication, whereas AOD-9604 is a GH fragment aiming for a direct lipolytic effect without raising GH/IGF-1, whose human efficacy was not established.[3]

Combining the two

Community "stacking" discussion pairs them on the theory of hitting fat metabolism by two routes, but there is no controlled trial of an AOD-9604/tesamorelin combination, and this page does not provide combination protocols or dosing. For the trial-backed compound, see the tesamorelin guide. (Searches pairing AOD-9604 with restricted weight-loss compounds are not covered here.)