Common questions
AOD-9604 questions, answered from the research
Direct answers to the questions people actually ask about AOD-9604, each cited to the published record.
Does AOD-9604 actually work?
Not for weight loss in humans, on the evidence. Across roughly six placebo-controlled trials in about 900 obese adults, the pivotal Phase IIb obesity trial did not produce statistically significant weight loss versus placebo, and the program was discontinued [9] [10]. It was well tolerated [5], and it reduced fat in mice [1] — but the human efficacy endpoint was not met.
Is AOD-9604 FDA approved?
No. AOD-9604 is not FDA-approved for any indication. The original anti-obesity development program was discontinued after the pivotal Phase IIb trial failed to meet its primary endpoint, and the compound never reached marketing approval anywhere [9] [10]. It is investigational, and it is not a dietary supplement.
Why was AOD-9604 discontinued as a pharmaceutical drug?
Because it did not work well enough. The pivotal Phase IIb obesity trial did not show statistically significant weight loss versus placebo, so Metabolic Pharmaceuticals discontinued the obesity development program around 2007 [9] [10]. The strong rodent fat-metabolism data simply did not translate into sufficient clinical efficacy — a common pattern for obesity drug candidates [8].
What happened in the AOD9604 Phase IIb clinical trial?
The Phase IIb obesity trial was the pivotal, mid-stage study designed to prove weight loss and optimal dosing. It did not demonstrate statistically significant weight loss versus placebo [9]. Tolerability across the broader program of about 900 subjects resembled placebo [5], but the failed efficacy endpoint led to the obesity program being discontinued around 2007 [10].
How much weight can you lose on AOD9604 peptide?
The honest answer from the trials is: no more than on placebo. The pivotal human obesity trial did not show statistically significant weight loss versus a dummy treatment [9] [10]. The most common community report mirrors this — no noticeable fat loss [5]. Strong rodent fat-loss data exists [1] [2], but it did not carry over to humans.
What is AOD-9604?
AOD-9604 is a synthetic 16-amino-acid peptide modelled on the C-terminal (tail) region of human growth hormone, residues 177-191, with an added N-terminal tyrosine [3]. It was engineered to copy growth hormone's fat-metabolising action without the growth-promoting, IGF-1-raising effects of the full hormone. It is a fragment of the hormone, not the hormone itself, and it is investigational.
What does the peptide AOD9604 do?
In animal studies it changes fat metabolism two ways: it inhibits acetyl-CoA carboxylase, the enzyme that makes new fat, and it raises beta-3 adrenergic receptor expression on fat cells, which drives fat-burning [1] [4]. After chronic treatment it reduced body weight and fat in obese mice [1] [2]. In humans, this did not translate into proven weight loss [9].
How does AOD-9604 work?
It works on fat cells, not on the growth-hormone receptor. It blocks new-fat synthesis via acetyl-CoA carboxylase and increases beta-3 adrenergic receptor expression, raising fat oxidation in obese mice [1] [4]. The chronic weight-loss effect in mice required functional beta-3 signalling [1]. Importantly, it does not bind the growth-hormone receptor and does not raise IGF-1 [3].
Is AOD-9604 safe?
Across the human trial program of about 900 obese adults, safety and tolerability were reported as indistinguishable from placebo and free of the adverse effects associated with full-length growth hormone [5]. Non-clinical evaluation found no genotoxic or toxicological concerns in rats and primates [6]. That said, long-term human safety data are limited — the longest published trial ran 24 weeks [9].
Does AOD9604 raise IGF-1 like HGH?
No. AOD-9604 was specifically designed not to raise IGF-1. Because it does not bind the growth-hormone receptor, it does not trigger the IGF-1 rise that full-length growth hormone causes [3]. Non-clinical evaluation found it generally safe and free of growth-hormone-type concerns [6]. This receptor-sparing design is the whole point of the fragment.
How does AOD9604 stimulate lipolysis without affecting the HGH receptor?
It acts on fat cells directly. In animal models the C-terminal fragment inhibits acetyl-CoA carboxylase via a membrane-derived second messenger and increases beta-3 adrenergic receptor expression, shifting metabolism toward fat oxidation — all without engaging the growth-hormone receptor [1] [4]. The fat effect lives in the fragment's interaction with the fat-cell membrane, not in growth-hormone signalling [3].
What is the half-life of AOD9604?
About 3 minutes after intravenous injection in a pig pharmacokinetic model [6]. The intact peptide is cleared rapidly, degrading by sequential removal of amino acids from its N-terminus in a cascade fashion [6]. This very short half-life is part of why the human program used an oral formulation taken regularly rather than relying on injection.
Is AOD9604 orally bioavailable or does it have to be injected?
It was developed and tested as an oral tablet — the primary route in the human obesity program [5]. Non-clinical work demonstrated oral absorption and characterised the metabolism after chronic oral administration in rats and primates [6]. Intravenous dosing was used for the Phase I human and animal pharmacokinetic studies, but the intended human form was oral.
Does AOD9604 work by activating beta-3 adrenergic receptors?
It increases beta-3 adrenergic receptor expression rather than directly activating the receptor. In obese mice, chronic treatment raised beta-3 receptor RNA toward lean-mouse levels, and in beta-3-knockout mice the chronic weight and fat response was abolished — so functional beta-3 signalling is required for the long-term effect [1]. The acute fat-oxidation effect, however, persisted even without beta-3 receptors [1].
Does AOD9604 affect insulin or blood sugar levels?
It was designed to avoid growth hormone's blood-sugar effects. Non-clinical evaluation found the compound free of genotoxic and toxicological concerns and generally safe after chronic oral administration in rats and primates [6], and unlike full-length growth hormone it does not engage the growth-hormone receptor or raise IGF-1 [3]. Detailed human glucose data is not prominent in the published trial literature.
What are the side effects of AOD9604?
In the human trials, side effects were hard to distinguish from placebo [5]. The most common community report is no fat loss rather than any adverse effect, with occasional injection-site redness or irritation that settles on its own. Notably absent are the growth-hormone-type effects — no water retention or joint puffiness — consistent with a receptor-sparing fragment [3]. Long-term human safety data are limited [9].
Is AOD9604 banned in competitive sports?
Yes. The World Anti-Doping Agency Prohibited List classifies growth hormone, its fragments and analogues under Section S2, the category under which AOD-9604 is prohibited at all times in sport [13]. As a growth-hormone fragment it must be treated as a prohibited substance by athletes, and dedicated assays can detect it. Despite some vendor claims to the contrary, it is on the prohibited list.
Is AOD9604 a steroid?
No. AOD-9604 is a peptide — a short chain of amino acids modelled on the tail region of human growth hormone [3] — not a steroid. Steroids are a different class of molecule with a different structure and mechanism. AOD-9604 acts on fat metabolism in animal models without engaging the growth-hormone receptor or raising IGF-1 [1] [3].
Does AOD9604 help with cartilage repair and osteoarthritis?
Only in animals so far. In a collagenase-induced knee osteoarthritis model in 32 rabbits, weekly intra-articular injection of 0.25 mg AOD9604 (with or without hyaluronic acid) reduced cartilage-degeneration scores versus saline [7]. This is a preclinical signal in rabbits with no published human osteoarthritis trials of AOD-9604, so it does not support any human joint-repair claim.
Does AOD9604 preserve muscle mass while reducing fat?
There is no human evidence for this. The pivotal human trial did not even demonstrate fat loss versus placebo [9] [10], and users generally report no change in strength, recovery, or muscle — consistent with a compound that does not engage the growth-hormone receptor [3]. Claims about muscle preservation are not supported by the published clinical record.
What is the mechanism of action of AOD9604?
In animal and cell models, AOD-9604 inhibits acetyl-CoA carboxylase (reducing new-fat synthesis) and up-regulates beta-3 adrenergic receptor expression in fat tissue (raising fat oxidation), without binding the growth-hormone receptor and without raising IGF-1 [1] [3] [4]. The long-term weight effect in mice depends on functional beta-3 signalling [1]. This mechanism is largely preclinical and did not translate to proven human fat loss.
Where do you inject AOD-9604?
This site does not provide administration or dosing instructions, because AOD-9604 is investigational with no approved human use. For context, the human obesity program used an oral tablet, not injection [5], and the published injection studies were in animals or for pharmacokinetics [6] [7]. The most common injection-related community report is mild, self-limiting site redness — a generic reaction, not a drug-specific effect.