Preloaded Autoinjector | AOD-9604 | 3ml Pen | 6mg

The aod 9604 pen is a preloaded 3ml research autoinjector holding 6mg of AOD-9604 in solution at 2mg/ml, which is 1.10 mM of the 16-residue hGH C-terminal analogue. One intramolecular disulfide between Cys7 and Cys14 governs everything that happens in the cartridge, and because the molecule has only two cysteines, the failure route is not rearrangement but covalent dimerisation.

Specification Table

AOD 9604 Solution Stability: What Changes Once the Cartridge Is Filled?

One bond does most of the work: the Cys7-Cys14 disulfide holds a 16-residue loop closed, and in water that bond can be reduced, exchanged with a neighbouring molecule, or eliminated altogether, while the rest of the sequence sits comparatively quiet.

The sequence is YLRIVQCRSVEGSCGF, with a free acid at the C-terminus. There is no methionine, no tryptophan, no asparagine and no aspartate, so the usual fast peptide routes are missing. Gln6 can deamidate to glutamate at +0.98 Da, glutamine being far slower at this than asparagine. Tyr1 and Phe16 can oxidise under light or trace metal. Everything else that matters is sulfur chemistry.

Thiol-disulfide exchange needs only a trace of free thiol to start, and once started it propagates: a reduced molecule attacks the disulfide of an intact one, opening it and generating a fresh thiol that attacks the next. Trace reductant in a buffer, trace copper or iron cycling through a redox couple, or ultraviolet photolysis producing thiyl radicals will each supply the initiating thiol. The peptide also carries the base-catalysed route, beta-elimination of the disulfide to dehydroalanine and a persulfide, which runs faster as pH rises above neutral and is the reason an alkaline formulation is a poor choice for this molecule.

With only two cysteines in the chain, one consequence follows that does not apply to multi-disulfide peptides. Scrambling cannot produce an alternative intramolecular isomer, because there is only one pair to connect. Exchange therefore has nowhere to go except between molecules, so the products are covalent dimers and higher oligomers rather than misfolded monomers. That makes the degradation profile unusually legible: a covalent dimer sits at 3630 Da, exactly twice the monomer mass, because two interchain bonds replace two intrachain bonds with no change in atom count. Reduction to the open dithiol adds 2 Da. Both are visible by mass spectrometry to anyone who looks for them.

Fibrillation is not the concern here. The peptide is short, hydrophilic and net positive near neutral pH, so amyloid-type assembly is unlikely; the aggregation that matters is covalent. Adsorption is moderate rather than extreme, since two arginines against one glutamate give a small positive charge that limits, without eliminating, loss to glass and polymer at low concentration.

There is no approved AOD-9604 product in any jurisdiction, so no reference formulation exists to copy. Development stopped in 2007, which means no regulator ever reviewed an excipient list, a pH, a preservative or a stability dataset for this molecule. Everything above is inference from disulfide chemistry, and no AOD-9604 forced-degradation study was located in the peer-reviewed literature.

What Does the AOD 9604 Pen Deliver Per Increment?

Six milligrams in 3 ml is 2 mg/ml, which is 1.10 mM at a molecular weight of 1815.1 g/mol, so a 0.01 ml increment carries 20 micrograms (11.0 nanomoles) and a 0.1 ml increment carries 200 micrograms (110 nanomoles).

The arithmetic runs in one direction only: a graduation is a volume, and mass follows from concentration. On an insulin-pattern scale one unit is 0.01 ml, so ten units is 0.1 ml and 200 micrograms. Whether this device is graduated that way is not on the product record and should be confirmed before any figure above is used, and the peptide calculator handles other graduations.

Against the published work the fill is concentrated. Adipocyte lipolysis and lipogenesis assays of the kind underlying Heffernan 2001 and Ng 2000 operate at micromolar to nanomolar peptide, so a 1.10 mM stock sits roughly a thousand to a million times above them, and any in vitro comparison starts with a long serial dilution. The rodent studies dosed by body weight in mg/kg rather than by fixed concentration, so there is no published concentration to match. No validated human figure exists to benchmark against, because the compound was never approved.

Does AOD 9604 Come in a Pen?

Yes, as a research-use-only preloaded device such as this one, and no as a licensed medicine: AOD-9604 has never been approved anywhere, so every preparation on the market is a vendor fill rather than a pharmaceutical product.

Can you get AOD 9604 in a pen with a regulator’s label on it? No, and the reason is historical rather than technical. Metabolic Pharmaceuticals took the compound through six clinical studies and a 24-week obesity trial that did not separate from placebo, and development was discontinued in 2007. Nothing has been filed since. The AOD 9604 pen form on this site is a laboratory article, and the fields to confirm before ordering any such device are listed on the preloaded autoinjector category page.

One identity point belongs here rather than in a footnote. AOD-9604 is not the plain hGH Fragment 176-191 that the same catalogue also sells; the two differ by a single N-terminal residue, tyrosine in place of phenylalanine. That substitution is worth 15.99 Da, which is the same mass difference as a single oxygen atom, so an intact-mass measurement alone cannot separate AOD-9604 from an oxidised batch of the plain fragment. Sequencing or co-elution against a characterised reference is the only way to tell them apart, a point most listings skip.

AOD 9604 Pen vs Vial: Which Format Suits the Work?

The aod 9604 pen vs vial choice comes down to disulfide handling: a sealed cartridge filled once under controlled conditions keeps the peptide away from repeated air exposure, while a lyophilized vial lets the laboratory choose a buffer, degas it, and control the redox environment the disulfide sits in.

The pen suits repeated equal draws from one lot across weeks. Each reconstitution of a vial is an opportunity to introduce dissolved oxygen, trace metal from a diluent, or a reducing contaminant, and for a single-disulfide peptide those are the exact inputs that start thiol exchange. A cartridge removes the transfer step and fixes the concentration at 2 mg/ml. The general comparison is set out in the pen versus vial article.

The lyophilized AOD-9604 5mg vial suits work where buffer composition is part of the experiment, where a chelator such as EDTA is wanted to suppress metal-catalysed thiol chemistry, or where the starting concentration should be far below 1.10 mM. A dry cake also stops the clock in a way a solution cannot, which matters more for a disulfide peptide than for a plain one. The nasal spray presentation answers a different question again, since it fixes both concentration and delivered volume.

AOD 9604 cost is on each product record and is not quoted here because it moves. The comparison worth running is cost per milligram of peptide confirmed by certificate, and for this molecule the certificate should state the disulfide state as well as the purity, since a lot that is 98% pure by area can still be part reduced. The AOD-9604 background article covers what else to ask for.

What the Product Record Does Not State

Four fields decide what this solution actually is, and none of them is published: the excipient system, the pH, the fill date, and whether the peptide was filled and released in the fully oxidised state.

The disulfide state is the one specific to this compound. A certificate reporting purity by reversed-phase area percent does not report how much of the material is closed-loop monomer, because the reduced form and the covalent dimer are separate peaks that a purity number can hide inside or exclude by integration window. Requesting the non-reduced peak assignment, or a free-thiol figure, answers a question that a purity percentage does not.

The pH matters twice, for beta-elimination above neutral and for the deamidation rate at Gln6. The excipient system matters because a chelator, an antioxidant or a preservative each changes the redox environment the disulfide sits in, and because whatever is present enters any assay the solution is added to. The fill date sets where the device sits on a stability curve nobody has published for AOD 9604 solution stability. Ask for all four against the lot certificate of analysis before quantitative work.

Verifying the AOD 9604 Pen and Confirming the Disulfide

Inspect the solution against a white background before each draw: it should be clear and colourless with no haze or particulate, though the informative checks for this peptide are analytical rather than visual, because covalent dimerisation produces no visible change at 2 mg/ml.

Three measurements cover the chemistry. Intact-mass LC-MS should show an average of 1815.1 Da; the reduced form appears at 1817.1 Da, +2 Da, and the covalent dimer at 3630 Da. Ellman’s assay with 5,5′-dithiobis(2-nitrobenzoic acid) quantifies free thiol directly by absorbance at 412 nm, and an intact preparation should show close to none. Reversed-phase HPLC separates monomer from dimer and from the reduced species, which usually elutes later than the compact closed-loop form.

Ultraviolet quantification is possible but weak. The molecule has one tyrosine and no tryptophan, so its extinction coefficient at 280 nm is roughly 1,600 per molar per centimetre including the cystine contribution, giving an absorbance near 1.8 for the neat 1.10 mM solution in a 1 cm path. That is enough for a content check against a reference standard and not enough to detect a loss of a few percent, which is a reason to run content by chromatography instead.

Let the device reach ambient temperature before actuating, since cold solution is more viscous and spring-driven mechanisms deliver less against a viscous load. Gravimetric verification once per device, actuating onto a tared vessel and converting mass by solution density, is worth more than trusting a nominal volume.

What Does the AOD-9604 Literature Actually Report?

A small file: a handful of rodent mechanistic papers from one group, a human tolerability summary, and one adequately powered obesity trial that did not beat placebo, after which development stopped in 2007.

Ng 2000 reported that the synthetic lipolytic domain reduced weight gain and raised adipose lipolytic activity in obese rats. Heffernan 2001, published in both Endocrinology and the International Journal of Obesity, reported that chronic treatment of obese and beta-3-adrenoceptor knockout mice increased fat oxidation and reduced body-fat gain, and that the effect did not appear to run through the classical growth hormone receptor. The design intent was to keep the lipolytic action of the hormone’s C-terminus while dropping its growth-promoting and IGF-1-raising effects, and the knockout work is what supports that separation.

Stier 2013 summarised six clinical studies and reported that the hexadecapeptide was non-immunogenic with a tolerability profile indistinguishable from placebo. That is a tolerability record rather than an efficacy record, and the distinction is the whole story of this compound. A 12-week randomised study reported roughly 1.8 kg greater loss than placebo, but the 24-week trial that followed showed no significant difference in weight against placebo, and the programme was halted.

What has not been studied is specific. No adequately powered efficacy trial has succeeded, there are no long-term human data, no controlled trial of any preloaded fixed-concentration device, and no published pharmacokinetic half-life that this page can state as verified beyond the observation that clearance after parenteral delivery is rapid. The molecular target for the metabolic effect remains incompletely defined.

What Is the Safety and Regulatory Position?

AOD-9604 is approved in no jurisdiction: not in the United States, the European Union, Australia, Japan or Canada, and development was discontinued in 2007, so this research preparation is not and cannot be an approved product.

In the United States an injectable peptide of this kind is handled as an unapproved new drug. AOD-9604 is not a lawful dietary-supplement ingredient in an injectable presentation, and marketing of the molecule as a cosmetic or topical ingredient by other parties confers no drug approval. Its specific status on the 2023 FDA list of peptides nominated for 503A compounding was not verified for this page and should be confirmed before any claim is made about it.

For sport the position is settled in practice if not in citation here. AOD-9604 has been treated as prohibited, and it became publicly known through the 2013 Essendon Australian Football League anti-doping case rather than through any approval. The exact class citation was not verified for this page, so athletes and sport researchers should check the current year’s list directly.

The compound is supplied for laboratory research only. Reported tolerability in six clinical studies was recorded with characterised trial material under monitoring, and says nothing about any vendor-filled solution, none of which has published identity, purity or stability data.

Published Literature

Each reference below was confirmed at source rather than copied from a secondary list. The list is short because the peer-reviewed record for this compound is short.

1. Heffernan MA, Summers RJ, Thorburn AW, et al. Endocrinology. 2001;142(12):5182-5189. DOI: 10.1210/endo.142.12.8522 PMID: 11713213
2. Ng FM, Sun J, Sharma L, et al. Hormone Research. 2000;53(6):274-278. DOI: 10.1159/000053183 PMID: 11146367
3. Heffernan MA, Thorburn AW, Fam B, et al. International Journal of Obesity and Related Metabolic Disorders. 2001;25(10):1442-1449. DOI: 10.1038/sj.ijo.0801740 PMID: 11673763
4. Jiang WJ, et al. In: Peptides: The Wave of the Future. 2001:714-715. DOI: 10.1007/978-94-010-0464-0_333
5. Stier H, Vos E, Kenley D. Journal of Endocrinology and Metabolism. 2013;3(1-2):7-15. DOI: 10.4021/jem157w

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