What Is AOD-9604?

What AOD-9604 is

AOD-9604 is a synthetic peptide — a short, lab-made chain of amino acids — copied from one specific region of human growth hormone (hGH). It is not the whole hormone. It is a small fragment, less than a tenth of the full growth-hormone molecule, taken from the tail end (the “C-terminal” region) of the protein.

The most useful thing to know about AOD-9604 is hidden in its name. AOD stands for Anti-Obesity Drug, and 9604 is an internal development code. This was never meant to be a “wellness peptide.” It was a deliberate pharmaceutical project: an attempt to build a prescription obesity drug out of the one part of growth hormone that mobilizes fat. Researchers at Monash University in Australia identified that fat-burning region in the 1990s, and a company called Metabolic Pharmaceuticals (a subsidiary of Calzada Ltd.) spent years and a series of human trials trying to develop it into an approved medicine.

That origin story is the throughline of this whole page. AOD-9604 behaves the way it does, is regulated the way it is, and gets discussed the way it does precisely because it is a drug candidate that ran the obesity gauntlet and didn’t make it through — not a supplement, not an approved medicine, and not a freshly discovered compound. Where we touch on whether it actually works, how much it costs, or how people obtain it, this page stays at the level of identity and points you to the dedicated pages instead.

How the molecule is built

Growth hormone is a large protein of 191 amino acids. AOD-9604 is essentially the last stretch of that protein — amino acids 176 to 191 — with one engineered change: an extra tyrosine residue added at the front end. Because of that addition, the precise compound is sometimes written as Tyr-hGH 177-191, and it is most commonly described simply as a “16-amino-acid C-terminal fragment of human growth hormone.”

That single added tyrosine is more important than it looks, and it leads to one of the most common points of confusion around this compound.

Note: “AOD-9604” and “HGH Fragment 176-191” are used as if they’re the same thing, but they aren’t strictly identical. AOD-9604 is the modified fragment (with the added tyrosine) that was actually tested in humans. The unmodified fragment 176-191 has not been studied in people the same way. In a regulated drug, that distinction would be controlled tightly. In the unregulated market, it isn’t — so two products carrying these labels can, in principle, be different molecules. This is the same identity-vagueness problem that surrounds other “fragment” and “analog” peptides sold outside the approval system.

The design intent behind the molecule is straightforward to state. Full growth hormone does several things at once: it promotes tissue growth, raises a downstream hormone called IGF-1, can worsen insulin sensitivity and blood sugar, and mobilizes fat. The premise of AOD-9604 was to isolate only the fat-mobilizing signal and leave the rest behind. In early human work, the fragment appeared to do exactly that — it acted on fat metabolism without raising IGF-1 and without the glucose disruption associated with full hGH. Whether that translated into meaningful weight loss is a separate question, and a more complicated one, which the evidence pages handle.

What it’s designed to do

At a high level, AOD-9604 is meant to act on fat tissue rather than on the brain. It is described as lipolytic — promoting the breakdown of stored fat (lipolysis) — and as discouraging the formation of new fat (lipogenesis). Mechanistic and animal research has linked its action to fat-cell signaling pathways, including beta-3 adrenergic activity in adipose tissue, working “peripherally” on fat cells rather than “centrally” on hunger.

The headline pharmacological claim — the reason anyone built this molecule — is fat-metabolism activity without the growth-hormone baggage: no IGF-1 elevation, no clear effect on blood glucose, no broad growth signaling. That is a genuinely interesting design, and it’s the kernel of truth that the marketing is built around.

It is also where the foundational page hands off. Whether AOD-9604 produces real, measurable fat loss in humans — as opposed to a tidy mechanism on paper — is exactly the question its clinical trial program tried and failed to answer convincingly. The short version: it was studied as an oral tablet, the early small-study signal was modest, and the larger pivotal obesity trial did not separate from placebo on its main endpoint, after which development was wound down around 2007. The numbers, the trial design, and the “does it work” verdict live on the evidence pages, not here.

What AOD-9604 is — and isn’t

Because so much marketing blurs categories, it helps to draw clean lines:

• It is not full growth hormone. It’s a fragment chosen specifically to lack growth hormone’s receptor binding and growth effects. “HGH for fat loss” is a marketing slogan, not an accurate description.
• It is not a GLP-1 medication. Semaglutide and tirzepatide work on appetite and blood-sugar regulation and have large, published weight-loss trials behind them. AOD-9604 works on fat cells and has essentially no appetite effect. They are different classes of molecule.
• It is not primarily an appetite suppressant. Its proposed value is appetite-neutral fat signaling, which is a very different mechanism from “eat less.”
• It is not an FDA-approved drug. It failed to win approval as an obesity medicine and is not approved for any therapeutic use in the US.

There is one regulatory wrinkle worth naming, because it gets misread constantly. Years ago AOD-9604 received a narrow, self-affirmed “Generally Recognized as Safe” (GRAS) determination for use as a food ingredient. That is a food-safety recognition for oral supplement use — it is not drug approval, it does not authorize therapeutic claims, and it does not apply to injectable or compounded forms. “It has FDA GRAS status” is true and “it’s FDA-approved” is false, and vendors routinely collapse the two.

Its US legal status in 2026

The 2026 regulatory picture for peptides is in motion but not finalized, and AOD-9604 sits in an unusual spot within it.

The headline 2026 development is that, in April 2026, the FDA removed a group of about a dozen peptides from “Category 2” of its 503A compounding list and scheduled a Pharmacy Compounding Advisory Committee (PCAC) review (July 23-24, 2026), with additional substances slated for review before early 2027. Importantly, removal from Category 2 does not mean a peptide is approved or even cleared to compound — it removes a “significant safety concern” designation, and the substance still has to clear PCAC review and formal rulemaking before it could be lawfully compounded. No “Category 1” placements have actually happened. The whole thing is a process that has started, not a finished reclassification.

AOD-9604 is not in that active cohort. It is not among the peptides removed from Category 2 in April 2026, it is not on the July 2026 PCAC docket, and it is not on the early-2027 list. AOD-9604 was looked at in an earlier compounding review and was not advanced toward the authorized bulks list. So its status isn’t “open and pending review” the way BPC-157 or TB-500 are — it’s closer to “reviewed earlier and not moved forward,” which leaves it effectively off the active track. Any vendor claiming AOD-9604 “became legal again in the 2026 reclassification” is misstating the situation.

The practical upshot for a US reader: AOD-9604 is not an approved drug, and it is not currently on the legitimate compounding pathway. That makes the question of how anyone obtains it genuinely complicated, which is why we treat access as its own subject. This status is current as of this page’s update date and could change as the 2026-2027 review process plays out.

For the full mechanics of the 503A/503B compounding system and how Category 1 vs Category 2 actually works, see the access pages linked below; this page only places AOD-9604 within that picture, it doesn’t re-explain the whole framework.

How people access it

Because AOD-9604 isn’t FDA-approved and isn’t on the active compounding pathway, the honest version of “how to get it” is mostly about understanding which routes are legitimate and which aren’t — not a shopping guide. Legal, supervised access to peptide therapy in general runs through licensed clinicians, telehealth providers, and compounding pharmacies. AOD-9604 specifically runs into a wall at the pharmacy level, because it isn’t a component a 503A pharmacy can lawfully compound from. The dedicated access pages walk through what that means in practice, what a prescription can and can’t accomplish, and why “we can get it, no problem” is a red flag rather than a convenience.

If the actual goal is fat loss rather than this particular molecule, it’s worth knowing that the route with real regulatory standing and large clinical evidence is the FDA-approved GLP-1 class (semaglutide, tirzepatide). That’s a different decision with a different evidence base — but it’s the lawful, well-studied comparison point, and we cover it separately.

A note for athletes

One identity fact matters regardless of the rest: AOD-9604 is prohibited in sport. The World Anti-Doping Agency (WADA) prohibited list explicitly names growth-hormone fragments, including AOD-9604 / hGH 176-191, as banned at all times. For any tested athlete, that’s true irrespective of intent, dose, or how the product is labeled. If you compete under anti-doping rules, this peptide is off-limits.

The bottom line

AOD-9604 is best understood not as a peptide that drifted into wellness clinics but as a failed obesity drug — a thoughtfully engineered growth-hormone fragment that was designed to burn fat without growth-hormone side effects, was tested in real human trials, and was shelved when it couldn’t demonstrate enough weight loss. Everything that’s appealing about it (the clean mechanism, the “GH without the downsides” pitch) and everything that’s frustrating about it (no approval, an unsettled legal status, an unproven real-world effect) traces back to that single fact. Use this page as the orientation point, then dig into the specific question you actually have — does it work, what does it cost, how would anyone access it — on the pages built for each.