AOD-9604

What is AOD-9604?

AOD-9604 is a synthetic analog of the C-terminal fragment (residues 176-191) of human growth hormone, modified with an N-terminal tyrosine. The fragment retains the lipolytic domain of the parent hormone while lacking the regions responsible for receptor-mediated growth signaling.

It is supplied by PX1 Research as a lyophilized reference compound for adipocyte and metabolic research where separating lipolytic activity from somatogenic activity is the experimental objective.

Mechanism of action

In adipocyte models AOD-9604 has been reported to stimulate lipolysis and inhibit lipogenesis without measurable effect on IGF-1 output or insulin sensitivity readouts, distinguishing it from intact growth hormone. The mechanism appears to be independent of the growth hormone receptor, with beta-3 adrenergic pathway involvement proposed in rodent studies.

Because it does not activate the somatogenic arm, AOD-9604 is frequently used as a negative control for growth-hormone-receptor-mediated effects in comparative experiments.

Laboratory handling and storage

AOD-9604 ships as a lyophilized powder in a sealed, tamper-evident vial. Store the unopened vial between −20°C and −80°C, protected from light, until the day of use. In this state the peptide is stable through the labeled expiration date printed on the lot documentation.

Purity, testing and Certificate of Analysis

Every PX1 Research lot of AOD-9604 is manufactured in the United States and released against a documented specification of ≥99% purity by reversed-phase HPLC, with identity confirmed on the same lot by high-resolution LC-MS against the theoretical mass of the sequence.

Research use only

AOD-9604 supplied by PX1 Research is intended strictly for in-vitro laboratory and research applications. It is not a drug, food, cosmetic, or medical device, and it is not for human or veterinary use, diagnosis, treatment, or consumption.

Researchers are responsible for handling the compound in accordance with their institution's safety procedures and all applicable local regulations. Safety data sheets and current lot documentation are available on this site.

Purity, identity and certificate of analysis

AOD-9604 is a modified fragment corresponding to residues 177-191 of human growth hormone with an added tyrosine at the N-terminus. Because it is a short sequence derived from a much larger protein, the impurity profile of a lot is dominated by truncation and deamidation products that differ from the target by a small mass increment — which is exactly the class of impurity a fast generic HPLC gradient fails to resolve.

PX1 reports lot-specific purity at ≥99% by reversed-phase HPLC on a shallow gradient, with identity confirmed by liquid chromatography-mass spectrometry against the theoretical monoisotopic mass of the modified 15-mer plus the N-terminal tyrosine. The added tyrosine is the feature that distinguishes AOD-9604 from the unmodified hGH fragment, and high-resolution mass data on the actual lot is what confirms it is present.

Endotoxin by kinetic chromogenic LAL, residual solvents by gas chromatography and water content by Karl Fischer titration are reported per lot, along with net peptide content. Net peptide content matters here because short fragments are frequently supplied as acetate salts, and salt and water together can account for a substantial fraction of the labelled mass.

How AOD-9604 compares to related research compounds

AOD-9604 is a fragment of growth hormone, not a secretagogue. Secretagogues such as Ipamorelin, CJC-1295 and Tesamorelin act on receptors upstream of the pituitary and are studied in terms of the endogenous release axis. AOD-9604 is a structural fragment studied in its own right, so comparisons between the two classes concern completely different points of intervention.

It is also distinct from full-length recombinant growth hormone, which is a 191-residue protein. The fragment retains only a short region of that sequence, and the published literature on the fragment therefore does not transfer from work on the intact protein. Methods sections should state which test article was used, because the two are routinely conflated in secondary sources.

In comparative in-vitro designs AOD-9604 frequently appears alongside secretagogue analogs specifically so that fragment-based and axis-mediated approaches can be separated experimentally rather than assumed equivalent.

Common research questions about AOD-9604

Is AOD-9604 the same as the hGH fragment 176-191? Closely related but not identical. AOD-9604 is the 177-191 region with an added N-terminal tyrosine, and that modification is part of the compound's definition. Material sold simply as "fragment 176-191" is a different test article and should not be substituted without saying so.

Does AOD-9604 stimulate growth hormone release? No — it is a fragment of the hormone, not a secretagogue, and the distinction is the reason it appears in comparative designs alongside GHRH analogs rather than as an alternative to them.

What purity is appropriate? ≥98% by reversed-phase HPLC on a resolving gradient is the working floor and ≥99% is the practical standard. Because the characteristic impurities are truncated versions of the same sequence, the impurity profile is as informative as the headline figure.

How is a lot verified on receipt? Confirm the vial lot matches the certificate, confirm the certificate carries the actual chromatogram and mass spectrum rather than a summary table, and confirm the reported mass corresponds to the tyrosine-modified 15-mer rather than the unmodified fragment.

Purity, identity and certificate of analysis

AOD-9604 is a 16-residue analog of the C-terminal 176-191 region of human growth hormone, carrying an added tyrosine at the N-terminus and a disulfide bridge that reproduces the loop geometry of the parent fragment. That disulfide is the analytical pressure point: a reduced or scrambled lot has the same amino-acid composition and nearly the same mass as correctly folded material, so a mass number alone does not establish identity. PX1 reports reversed-phase HPLC purity for the specific lot in the vial against a ≥99% specification, with the chromatogram published rather than summarized.

Identity is confirmed by liquid chromatography-mass spectrometry against the theoretical monoisotopic mass of the intact, oxidized 16-mer. Because the reduced form differs from the oxidized form by only two mass units, the release panel reads the isotope envelope rather than a nominal mass, and retention time relative to a characterized reference lot is treated as a second identity criterion.

Each AOD-9604 lot additionally carries endotoxin by kinetic chromogenic LAL, residual solvent screening by gas chromatography, and water content by Karl Fischer titration. Water content and net peptide content together determine how much peptide is actually present per labelled milligram — the figure a laboratory needs when preparing a quantitative reference standard, which purity alone never answers.

How AOD-9604 compares to full-length growth hormone research tools

AOD-9604 was designed to isolate the lipid-metabolism-associated region of human growth hormone from the receptor-binding regions that drive the somatotropic signaling of the full-length hormone. In comparative in-vitro designs it is therefore used as the fragment arm against recombinant hGH as the full-length arm, allowing an effect to be attributed to the 176-191 region rather than to growth hormone receptor engagement generally.

Researchers studying growth hormone secretagogues frequently run AOD-9604 alongside a GHRH analog such as Tesamorelin and a ghrelin-receptor agonist such as Ipamorelin. Those two act upstream, on secretion; AOD-9604 acts as a structural fragment downstream of secretion, so the three occupy genuinely different positions in an experimental matrix rather than being interchangeable.

Because the fragment is short and unlipidated, its handling profile is closer to that of BPC-157 or KPV than to acylated incretin analogs such as PX1-S or PX13-R, which need shallow chromatographic gradients and surfactant-aware labware.

Common research questions about AOD-9604

How does AOD-9604 differ from the 176-191 fragment itself? AOD-9604 adds an N-terminal tyrosine to the natural 176-191 sequence, which improves synthetic tractability and analytical detectability while preserving the disulfide-constrained loop.

Why does the certificate report water content? Because a lyophilized cake retains residual moisture. A vial can be 99% pure by HPLC and still contain measurably less peptide per labelled milligram than assumed, which changes every calculated concentration downstream.

Which storage state is stable longest? The lyophilized state, at -20 °C and protected from light, through the labelled expiration. Aqueous solution is the least stable state for any disulfide-containing peptide and is treated as a short-lived working preparation.

Is AOD-9604 supplied for human use? No. PX1 supplies AOD-9604 strictly as a research reference compound. It is not for human or veterinary use, and no dosing guidance is provided.