Apex Laboratory · Compound explained · Evidence checked September 8, 2026
If you are asking whether AOD9604 works, how it differs from HGH fragments, or what its side effects are, the most useful starting point is the actual experiment. Less weight gained by rats, a change in a human pain score and successful treatment of obesity are different outcomes. This guide follows the compound through those questions without converting research results into a personal-use schedule.
What is AOD9604?
AOD9604 contains 16 amino-acid residues: an added tyrosine followed by residues 177–191 of human growth hormone. Two cysteines form a disulfide bond. This small peptide is different from the full 191-residue hormone, from a drug that stimulates growth-hormone release, and from an unspecified product called “HGH fragment.” Cox and colleagues, 2015
The official GSRS substance record, UNII 7UP768IP4M, lists AOD9604, AOD-9604, LAT8881 and LAT-8881 together. That alias matters: searching only “AOD9604” misses later studies filed under LAT8881. A substance identifier connects the names; it does not approve a medicine or verify a supplier’s formulation.
AOD9604 versus AOD9401 and HGH Fragment 176–191
One residue changes the identity
Compare the defined sequences, not only the number in a product name.
In the mature human hormone, position 176 is phenylalanine. AOD9604 instead has tyrosine followed by the same final 15 residues. AOD9401 omits that added residue. Papers using those related fragments can explain the research history, but their results should not be silently reassigned to AOD9604.
PubChem CID 71300630 gives the disulfide-linked reference formula as C78H123N23O23S2, approximately 1,815.1 g/mol. An acetate or another specified preparation requires its own salt and composition information. The reference mass alone cannot establish the mass basis printed on a vial.
Does AOD9604 work for weight loss in people?
The largest historical trial did not demonstrate a significant advantage over placebo. This is more informative than a before-and-after photograph or a favorable animal result. FDA’s 2024 assessment reproduces the sponsor’s OPTIONS trial design and outcome; the original company filing is also available.
OPTIONS: the question was additional weight loss
Oral AOD9604 was compared with placebo while participants followed a dietitian-supervised diet and exercise program. Weight change attributable to the compound had to be distinguished from changes in the placebo group.
The source documents agree on 502 randomized participants. They differ on the earlier enrollment count: FDA and the sponsor filing report 536, while the 2013 safety paper reports 534. This guide uses the agreed randomized denominator and keeps the discrepancy visible. It does not relabel all enrolled participants as analyzed or successfully treated. FDA review, printed pages 21–22 · Original sponsor filing.
Early development: an investigational hypothesis
A 2004 development review described phase IIa work underway. That historical notice is not a completed efficacy result. Wilding and colleagues, 2004
A smaller positive signal with incomplete reporting
FDA discussed a 12-week conference abstract from an earlier obesity study. Its reported differences were small, dose response was not straightforward, and a full methods-and-results publication was not located by the reviewers. That limited report should not become a guaranteed number of kilograms lost.
2007: obesity development ended after the larger trial
The sponsor announced on February 21, 2007 that the phase IIb results did not support commercial development for obesity. This was an unsuccessful obesity program, not evidence that the molecule had no biological activity in every model.
There is therefore no supported personal answer to “How much weight will I lose?” or “How many weeks until it works?” in these trials. The result also does not establish that a different, untested retail formulation would succeed where the studied formulation did not.
Why did the animal results look promising?
In obese Zucker rats, a direct AOD9604 experiment reported substantially less body-weight gain over 19 days. The treated animals still gained weight. Calling this “more than 50% weight loss” changes the meaning of the finding. Ng and colleagues, 2000
Less gain is not the same as losing half the body weight
Mean grams gained over 19 days in obese Zucker rats; the original abstract reports ±0.6 g and ±0.8 g alongside these means.
A separate 14-day experiment in obese and lean mice measured increased fat oxidation and circulating glycerol alongside reduced weight gain in the obese group. Unlike intact growth hormone in that experiment, AOD9604 did not produce the measured hyperglycemia or reduction in insulin secretion. Those are specific endpoints under specific conditions, not proof that all hormonal or metabolic side effects are absent. Heffernan and colleagues, 2001
| Material and model | What was measured | What it does not establish |
|---|---|---|
| AOD9401, obese mice; saline n=8, peptide n=10 | Lower weight gain from day 16 during a 30-day study, with no food-intake difference. Heffernan and colleagues, 2000 | An exact AOD9604 effect or a human treatment result. |
| AOD9401, obese Zucker rats | Mean adipocyte diameter 110 to 80 μm during a 20-day experiment; lipid-enzyme changes. Ng and colleagues, 2000 | Equivalent changes in a person’s fat cells or body composition. |
| AOD9401, isolated human donor fat tissue | Changes in lipolysis and lipogenesis outside the body. Heffernan and colleagues, 2000 | A trial in people receiving the compound. |
| Earlier hGH 177–191 fragment and intact hGH models | Some studies found reduced fat synthesis without a significant rise in fat breakdown. Wu and colleagues, 1993 Ng and colleagues, 1990 | A uniform fragment effect across species, tissues and assays. |
Here, lipolysis means breaking down stored fat, lipogenesis means making fat, and fat oxidation means using fatty acids as fuel. Measuring one does not automatically demonstrate a sustained reduction in body fat. The early C-terminal-fragment program, including the 1982 paper, also predates AOD9604’s current name; that indexed record has no abstract from which to confirm a numerical result. Ma and colleagues, 1982
What did the later LAT8881 human studies find?
On September 8, 2026, our exact AOD-name ClinicalTrials.gov query returned no records, while the LAT8881 query returned three completed studies with posted results. The GSRS identity link is why both names were checked. These trials concern investigational pain treatments, not fat loss or consumer vials.
Neuropathic pain: 53 enrolled, no significant primary difference
NCT03865953 compared oral LAT8881 and placebo in a crossover design, with four-week treatment periods. The primary per-protocol analysis contained 50 participants in each treatment condition; these were not 100 independent people.
The adjusted active-minus-placebo difference in change on an 11-point pain scale was −0.14 points (95% CI −0.76 to 0.49; p = 0.67). The interval crosses zero, so the primary comparison did not demonstrate an advantage.
The uncertainty spans no difference
Adjusted difference in pain-score change: LAT8881 minus placebo.
Acute migraine: 21 enrolled
NCT04153409 was a small crossover study. Its per-protocol primary outcome used 16 LAT8881 and 17 placebo treatment observations. None of the seven posted adjusted time-point comparisons showed a statistically significant advantage. The registry explicitly describes exploratory analysis without correction for multiple comparisons.
Lumbar nerve-root pain: 26 enrolled across two parts
NCT05298306 included an initial safety part and a crossover pain part. The pain analysis contained 17 participants under each condition. Its posted adjusted comparisons also did not demonstrate a significant advantage. It studied an intravenous formulation; it does not validate a retail subcutaneous product or a weight-loss claim.
The two smaller exploratory trials did not have formal sample-size calculations, according to their records. The 53-person neuropathy trial did state a power assumption. It would be inaccurate to describe all three as either definitive proof of no possible effect or positive clinical confirmation.
How does AOD9604 work—and what changed in 2026?
The answer is more specific than “it burns fat through the growth-hormone receptor.” Older cell experiments did not show competition for that receptor or growth-hormone-like proliferation. In beta-3 adrenergic receptor knockout mice, chronic effects were lost but an acute fat-oxidation response remained. That pattern does not identify AOD9604 as a direct beta-3 agonist. Heffernan and colleagues, 2001 Heffernan and colleagues, 2001
Older metabolic work
Measured fat metabolism and narrowed GH-receptor and beta-3 explanations. It did not settle one complete human fat-loss pathway.
2026 neuropathy work
Identified LanCL1 using a labeled metabolite-derived probe, then tested its importance with gene knockdown in rats.
Remaining boundary
A mechanistic finding in injured sensory nerves is not proof of obesity efficacy, universal pain relief or a safe personal regimen.
The 2026 primary study linked lanthionine synthetase C-like protein 1 (LanCL1) to LAT8881’s effects in rodent neuropathic-pain models. A photoaffinity conjugate of LAT9991F, a metabolite-related peptide, captured the protein; excess LAT8881 reduced the capture signal. Knocking down LanCL1 in the dorsal root ganglion eliminated the measured LAT8881 response. This is stronger evidence than simply observing a change in receptor expression. Spanswick and colleagues, 2026
The same paper found little effect in inflammatory-pain models or ordinary nociceptive responses. It left parts of the downstream signaling unresolved and involved researchers linked to the developer. Its methods distinguish the parent LAT8881 from LAT9991 and LAT9991F. None of those details should be flattened into a universal “confirmed fat-burning receptor” claim.
What about joints, cartilage and infection research?
A 2015 study used 32 rabbits with experimentally induced knee osteoarthritis. Cartilage morphology, histology and lameness favored AOD9604-containing conditions, with the combination of AOD9604 and hyaluronic acid performing best on the reported comparisons. This was an induced rabbit disease model, not a clinical cartilage-regeneration trial. Kwon and colleagues, 2015
In 2023, researchers studied LAT8881 and LAT9991F in cell systems and mice with severe influenza A infection. They reported lower viral burden and inflammatory markers, and improved disease outcomes under particular experimental conditions. The parent peptide and its metabolite were evaluated separately; the antiviral-combination experiment used LAT8881. These findings do not establish an approved infection treatment or predict the effects of a consumer product. Harpur and colleagues, 2023
Analytical research adds another kind of information. Cox and colleagues identified candidate breakdown products after incubating AOD9604 in serum and urine. A comparatively stable nine-residue fragment is not the intact peptide, and a laboratory detection result is not a human therapeutic half-life. Cox and colleagues, 2015
What are the side effects and safety uncertainties?
The frequently cited 2013 six-trial safety paper reported no increase in serum IGF-1, no identified anti-AOD9604 antibodies in the samples tested, and generally favorable tolerability. Most importantly, it is a safety summary rather than a full demonstration of weight-loss efficacy. The studies were funded by the developer, and the authors disclosed employment, consulting or financial connections.
That paper still reports adverse events. In an early intravenous study, chest tightness and euphoria were considered possibly related; other studies reported headaches and gastrointestinal complaints. “No event judged drug-related” and “no event occurred” are different statements.
Read the uncertainty alongside the reassuring summary
FDA’s 2024 review identified serious events in the historical oral program, including diarrhea, chest tightness and cancers. It also said the reports provided insufficient information to determine their relationship to AOD9604, particularly the cancers. This is neither proof that AOD9604 caused those events nor a basis for declaring it free of serious risk.
FDA clinical safety discussion and conclusions. Current FDA safety wording also says causality is unclear.
A 2014 developer-funded animal toxicology paper interpreted its studies favorably. FDA’s later assessment raised unresolved concerns from the same limited evidence, including bone and liver findings and equivocal genotoxic signals. These experimental signals do not quantify human risk, but they make “proven completely safe” an unjustified summary.
Formulation quality matters too: disulfide chemistry, peptide impurities and aggregates can change a preparation. The current FDA safety page lists AOD9604 among substances with withdrawn nominations and continuing safety concerns. Historical oral or intravenous observations do not establish the safety of a different route or retail preparation.
Is AOD9604 FDA approved? What does GRAS mean?
AOD9604 is not an FDA-approved weight-loss medicine. FDA’s assessment found that the evidence did not support its effectiveness for obesity. A clinical-trial registration and a UNII substance record are not approvals.
The 2013 paper described an expert-panel GRAS conclusion for intended food uses. FDA explains that GRAS concerns specified conditions of use in food. It does not mean that an injectable preparation is approved, or that a drug works for obesity. This guide does not certify food-use status for any particular Apex product.
For sport, WADA’s current Prohibited List explicitly names AOD-9604 among growth-hormone fragments prohibited at all times. A research-use label does not remove that sporting rule.
What should a researcher check in the material?
Start with the defined sequence and preparation, then read the actual sample record. Identity testing, HPLC peak-area percentage and measured content answer different questions. A high chromatographic percentage does not establish clinical efficacy, identify an unlinked shipping lot or prove sterility unless that was tested.
The COA reading guide, HPLC explanation and Lab Verified library explain those checks. The AOD9604 research-material page shows current configurations and availability.
For related but different biology, see the growth-hormone-axis overview, Sermorelin guide and Tesamorelin guide. AOD9604 is not a GHRH analogue. Similar marketing language does not establish that it can replace or safely combine with a different treatment.
For laboratory research only. Not for human or veterinary use. This educational guide does not provide dosing, injection, reconstitution, cycling or combination instructions.
Frequently Asked Questions
What is AOD9604?
AOD9604 is a synthetic 16-residue peptide consisting of an added tyrosine followed by human growth hormone residues 177–191, with a disulfide bond. LAT8881 is another development name for the same sequence. It is different from full-length growth hormone and the 15-residue AOD9401 fragment.
Does AOD9604 work for weight loss?
The historical obesity program did not establish a significant weight-loss benefit in its largest trial. That trial randomized 502 adults and compared oral AOD9604 with placebo alongside diet and exercise. Positive rodent findings do not establish how much weight a person would lose.
Is AOD9604 the same as HGH Fragment 176–191?
The names are often mixed together. Native hGH residues 176–191 begin with phenylalanine, whereas AOD9604 has tyrosine at that position. AOD9401 instead contains the final 15 residues. The actual sequence is more precise than a marketplace fragment label.
Is AOD9604 the same as LAT8881?
The official GSRS substance record lists AOD9604 and LAT8881 together with the same 16-residue sequence and disulfide linkage. LAT8881 trials concern specific investigational formulations; this identity link does not establish that a retail vial matches those formulations.
Does AOD9604 raise growth hormone or IGF-1?
AOD9604 is a fragment-derived peptide, not a growth-hormone-releasing drug. Older receptor experiments did not show growth-hormone-receptor binding or proliferation, and the historical human safety summary did not report increased serum IGF-1. Those findings do not prove universal hormonal neutrality or long-term safety.
What are the possible side effects?
The human record includes headaches, gastrointestinal complaints and other adverse events. Some early intravenous events were considered possibly related. FDA also identified serious events in the historical program but said there was insufficient information to establish their relationship to AOD9604. Different formulations and routes cannot share an assumed safety profile.
How long does AOD9604 take to work?
No reliable personal weight-loss timeline follows from the trials reviewed here. A metabolite detection result, an animal observation and a human clinical benefit are different measurements. The evidence does not establish a dosing interval or a guaranteed duration of effect for a research product.
Can AOD9604 be combined with tirzepatide, HGH or Sermorelin?
The studies described here do not establish the effectiveness or safety of those combinations. AOD9604, growth hormone, GHRH analogues and incretin medicines have different structures and evidence. Similar weight-management claims do not supply a clinical combination protocol.
Is AOD9604 FDA approved or does GRAS mean it is approved?
AOD9604 is not an FDA-approved weight-loss medicine. A food-use GRAS opinion, a substance identifier and a clinical-trial registration are separate from drug approval. FDA continues to identify safety uncertainties concerning compounded AOD9604.
What can an AOD9604 COA establish?
A report can document the methods and results for its identified sample. Identity, chromatographic peak-area percentage and measured content answer different questions. A report does not by itself establish the shipping lot, human efficacy, sterility unless tested, or equivalence to an investigational medicine.
References and primary sources
Primary literature and current registry records were checked on September 8, 2026. The older literature, the two human development programs and their different formulations are separated above.
- Heffernan MA et al. Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. American journal of physiology. Endocrinology and metabolism. 2000. PMID 10950816.
- Ng FM et al. Molecular and cellular actions of a structural domain of human growth hormone (AOD9401) on lipid metabolism in Zucker fatty rats. Journal of molecular endocrinology. 2000. PMID 11116208.
- Ng FM et al. Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Hormone research. 2000. PMID 11146367.
- Heffernan MA et al. Increase of fat oxidation and weight loss in obese mice caused by chronic treatment with human growth hormone or a modified C-terminal fragment. International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity. 2001. PMID 11673763.
- Heffernan M et al. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology. 2001. PMID 11713213.
- Wilding J et al. AOD-9604 Metabolic. Current opinion in investigational drugs (London, England : 2000). 2004. PMID 15134286.
- Ng FM et al. Effects of exogenous growth hormone on lipid metabolism in the isolated epididymal fat pad of the growth hormone-deficient little mouse. Journal of molecular endocrinology. 1990. PMID 1969738.
- Cox HD et al. Detection and in vitro metabolism of AOD9604. Drug testing and analysis. 2015. PMID 25208511.
- Kwon DR et al. Effect of Intra-articular Injection of AOD9604 with or without Hyaluronic Acid in Rabbit Osteoarthritis Model. Annals of clinical and laboratory science. 2015. PMID 26275694.
- Ma GY et al. The mechanism of the hyperglycaemic action of synthetic peptides related to the C-terminal sequence of human growth hormone. Biochimica et biophysica acta. 1982. PMID 6810951.
- Wu Z et al. Antilipogenic action of synthetic C-terminal sequence 177-191 of human growth hormone. Biochemistry and molecular biology international. 1993. PMID 8358331.
- Ogru E et al. The conformational and biological analysis of a cyclic anti-obesity peptide from the C-terminal domain of human growth hormone. The journal of peptide research : official journal of the American Peptide Society. 2000. PMID 11152298.
- Harpur CM et al. Naturally derived cytokine peptides limit virus replication and severe disease during influenza A virus infection. Clinical & translational immunology. 2023. PMID 36969366.
- Spanswick DC et al. Lanthionine synthetase C-like protein 1 (LanCL1): a therapeutic target for neuropathic pain. Pain. 2026. PMID 42263267.
- Stier, Vos and Kenley. Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans. 2013. DOI 10.4021/jem157w.
- Moré and Kenley. Safety and Metabolism of AOD9604, a Novel Nutraceutical Ingredient for Improved Metabolic Health. 2014. DOI 10.14740/jem213w.
- FDA. AOD-9604-related bulk drug substances: December 2024 advisory-committee briefing.
- NCT03865953; NCT04153409; NCT05298306. Current posted results retrieved September 8, 2026.
