AOD-9604

TL;DR

- AOD-9604 is a lab-made copy of the tail end of human growth hormone (amino acids 176 to 191), studied as a fat-loss agent meant to trigger fat breakdown without raising IGF-1 the way full growth hormone does. - The published human record does not support AOD-9604 as an effective weight-loss drug: a small early trial suggested modest effects, but the larger confirmatory obesity program did not meet its primary weight-loss endpoint, and no weight-loss indication was approved (Stier et al., 2013). - The proposed fat-burning action rests mainly on animal work, where AOD-9604 reduced body fat and restored beta-3 adrenergic receptor signaling in obese mice (Heffernan et al., 2001). - By contrast, tesamorelin, a growth-hormone-releasing hormone analog, cut visceral fat by about 15.2 percent in a controlled human trial (Falutz et al., 2007). - Growth hormone secretagogues that do raise IGF-1, such as MK-677, also raised fasting glucose and lowered insulin sensitivity (Nass et al., 2008), the trade-off AOD-9604 was designed to sidestep. - The strongest human weight-loss data today belong to incretin drugs like semaglutide (about 15 percent; Wilding et al., 2021) and tirzepatide (up to about 22.5 percent; Jastreboff et al., 2022), a tier AOD-9604's human data do not reach.

What is AOD-9604?

AOD-9604 is a synthetic peptide that copies the last stretch of human growth hormone, the amino acids at positions 176 to 191.

Full human growth hormone is a large protein with many jobs: it signals growth, raises the hormone IGF-1, and changes how the body handles fat and sugar. Researchers noticed that a small piece near the end of the molecule, sometimes called the lipolytic domain, seemed tied to the fat-signaling part of the hormone. AOD-9604 (also written AOD9604 or "hGH fragment 176 to 191") is a made-to-order version of that piece.

The development idea was simple: keep the fat-signaling and drop the rest. If the fragment could push fat breakdown without raising IGF-1 or disturbing blood sugar, it might act as a cleaner fat-loss tool than growth hormone itself. That was the hypothesis. As the sections below show, human trials did not confirm it as a weight-loss drug.

How is AOD-9604 supposed to work?

The proposed mechanism is that AOD-9604 nudges fat cells toward breaking down stored fat (lipolysis) and away from storing new fat (lipogenesis), without the IGF-1 rise linked to full growth hormone. This idea comes largely from animal studies: in obese mice, both human growth hormone and AOD-9604 reduced body weight and body fat and restored suppressed beta-3 adrenergic receptor signaling, and the fat-reducing effect was lost in beta-3 receptor knockout mice, which points to that pathway as a route of action (Heffernan et al., 2001).

To see why that mattered, it helps to look at the wider growth hormone axis. Compounds that raise growth hormone and IGF-1 can carry metabolic costs. In a controlled study, the oral secretagogue MK-677 raised fasting glucose and lowered insulin sensitivity (Nass et al., 2008). Other agents in this space, such as CJC-1295, sustain higher growth hormone and IGF-1 levels (Teichman et al., 2006), and ipamorelin acts as a selective growth hormone secretagogue (Raun et al., 1998). Each of these works by turning the growth hormone signal up.

AOD-9604 was pitched as different: a fragment that touches fat metabolism without turning that signal up. That lipolytic activity was documented in preclinical models (Heffernan et al., 2001), but preclinical signals do not always carry into people, and here they largely did not once the compound reached larger human trials (Stier et al., 2013).

Does AOD-9604 cause weight loss in humans?

No, not convincingly: an early trial hinted at modest effects, but the larger confirmatory obesity study did not meet its primary weight-loss endpoint, and no weight-loss indication was approved (Stier et al., 2013).

This is the single most important thing to understand about AOD-9604. The compound moved through human obesity testing sponsored by Metabolic Pharmaceuticals. A smaller, earlier phase 2 study suggested a modest weight reduction, but the larger phase 2b program (hundreds of clinically obese adults randomized to 0.25, 0.5, or 1 mg or placebo over 24 weeks) did not separate from placebo on the primary weight-loss endpoint, and the obesity program did not advance to an approved product (Stier et al., 2013). Peer-reviewed human efficacy data remain limited and are best summarized as largely negative at the confirmatory primary endpoint. If you see marketing that presents AOD-9604 as a proven fat-loss drug, note the gap between that claim and the published human record.

For comparison, peptides and drugs that do have positive controlled human data sit in a different tier: - Tesamorelin reduced visceral adipose tissue by about 15.2 percent (Falutz et al., 2007). - Semaglutide produced about 15 percent mean weight loss in a large trial (Wilding et al., 2021). - Tirzepatide reached up to about 22.5 percent (Jastreboff et al., 2022), and retatrutide up to about 24.2 percent at 48 weeks (Jastreboff et al., 2023).

AOD-9604's human data do not reach that level of evidence. Any decision about weight management belongs with a qualified clinician who can weigh options that have actual outcome data.

What doses of AOD-9604 has research used?

There is no validated, approved AOD-9604 dose for weight loss, and this page will not tell you what to take; a qualified clinician is the right person for any personal dosing question.

The human obesity program tested daily oral doses of 0.25, 0.5, and 1 mg against placebo, but because the confirmatory trial did not meet its primary weight-loss endpoint, no efficacy-based dose was established (Stier et al., 2013). That is different from a compound like tesamorelin, where a controlled trial documented an outcome (about 15.2 percent visceral fat reduction; Falutz et al., 2007) under clinician-managed use for a specific indication, which is still not general advice. For AOD-9604, there is no research-validated efficacy dose to report, so presenting a dosing table here would imply a certainty the data do not support.

What research can offer is a comparison of where AOD-9604 sits next to fat-loss peptides and drugs that have human outcome data. That is the table below.

How does AOD-9604 compare to tesamorelin and other fat-loss peptides?

Tesamorelin and the incretin drugs have positive controlled human data for fat or weight reduction, while AOD-9604's human efficacy data are limited and largely negative at the confirmatory endpoint, so they do not belong in the same evidence tier.

The pattern is clear: the compounds with the strongest human fat or weight data either raise the growth hormone axis on purpose (tesamorelin) or work through a different pathway entirely (semaglutide, tirzepatide). AOD-9604's selling point, fat action without IGF-1, is attractive on paper and had some support in mice (Heffernan et al., 2001), but the human efficacy that would make it useful did not show up in the larger trial (Stier et al., 2013).

How long does AOD-9604 stay in the body?

Peer-reviewed pharmacokinetic data for AOD-9604 are limited, so a precise half-life figure is not something this page can cite with confidence.

As a general rule, small peptide fragments are broken down quickly by enzymes in the blood and tissues, which tends to give them short plasma half-lives measured in minutes to a few hours rather than days. AOD-9604 is a short fragment, so the same principle would apply. Because published, specific half-life values for AOD-9604 are limited, treat any exact number you see as an estimate rather than a settled fact, and route pharmacokinetic questions to a clinician or the primary literature.

What are the reported side effects of AOD-9604?

In the human trials that were run, AOD-9604 was reported to be well tolerated, with a safety and tolerability profile that was hard to distinguish from placebo and no growth-hormone-type adverse effects (Stier et al., 2013). The catch is that this comes from a program without a positive efficacy result, so the long-term safety picture during effective, sustained use was never established.

The theoretical appeal of AOD-9604 was that, by not raising IGF-1, it might avoid the metabolic downsides seen with growth hormone secretagogues. That matters because IGF-1-raising agents can carry real trade-offs: MK-677, for example, raised fasting glucose and lowered insulin sensitivity in a controlled study (Nass et al., 2008). Consistent with its design, AOD-9604 showed no negative effect on glucose tolerance in human testing (Stier et al., 2013), though that is a safety observation rather than a demonstrated long-term result. Anyone considering AOD-9604 for any reason should discuss it with a qualified clinician who can review their personal health history.

Is AOD-9604 an approved weight-loss medicine?

No: AOD-9604 is not an approved medicine for weight loss, and this page is educational rather than medical advice.

The compound is handled as a research material, not a licensed drug, and its human obesity program did not produce an approved weight-loss product after the larger confirmatory trial missed its primary endpoint (Stier et al., 2013). Peptara Labs presents AOD-9604 in a research context only. Nothing here is a promise of results, a treatment claim, or a dosing instruction. Health and weight decisions belong with a qualified clinician.