AOD-9604 Testing & Verification
Independent RP-HPLC-UV analysis of your AOD-9604 sample. Of the compounds we see, this is one of the more frequently substituted — which makes an identity check against a certified reference standard the whole point.
What AOD-9604 is
AOD-9604 is a modified analog of the C-terminal fragment of human growth hormone, the hGH 176-191 region, carrying an added N-terminal tyrosine residue. It is a short peptide of roughly sixteen residues containing two cysteines that form an intramolecular disulfide bridge, so the intended molecule is a small cyclic loop rather than a simple linear chain. That added tyrosine matters twice over: it is part of what distinguishes AOD-9604 from the plain unmodified hGH fragment, and it is an aromatic residue that absorbs in the 275-280 nm region, giving the compound a genuine ultraviolet signature to work with — something most short research peptides do not have. AOD-9604 is sold on the research-chemical market as a lyophilized powder, often at relatively high labeled milligram amounts, with no regulated guarantee of identity or content.
Why get your AOD-9604 independently tested
- Disulfide integrity: the intended molecule is the oxidized, cyclic form with an intramolecular bridge between its two cysteines. Incomplete oxidation during manufacture leaves the reduced open-chain peptide, and intermolecular pairing produces dimers and higher aggregates. These are chemically distinct species with different reversed-phase retention from the correctly folded monomer, so they show up as shifted or additional peaks rather than as good product. Identity by co-elution with a certified standard plus area-percent purity is how a batch that never closed its loop properly becomes visible.
- Frequent counterfeiting and substitution: AOD-9604 is among the more commonly substituted compounds in the research market, typically with the cheaper unmodified hGH fragment 176-191 (which lacks the N-terminal tyrosine) or with an unrelated peptide in an identical vial. The missing tyrosine is analytically useful here — a sample without it produces no absorbance band in the 275-280 nm region, while genuine AOD-9604 does. Combined with retention-time match to a certified standard, that gives the identity call more to stand on than it would have for a peptide with no aromatic residue.
- High labeled masses make the salt and water share material: AOD-9604 is often sold at labeled amounts well above the typical research peptide, and the larger the number on the label, the more absolute mass a counterion and residual-moisture fraction represents. Lyophilized powder weight includes acetate or TFA counterions, water, and any bulking agent. The net-peptide assay reports milligrams of peptide specifically, which is the figure to compare against the label.
- The vial you received is not the batch the supplier tested: a disulfide-bonded peptide is susceptible to thiol-disulfide exchange, dimerization, and related degradation over time, and that chemistry keeps running through shipping, temperature excursions, and reconstitution. A supplier purity figure describes material at manufacture. Area-percent purity measured on your sample describes the material actually in your hands, including anything generated since it left the factory.
What we measure on AOD-9604
Each AOD-9604 sample is analyzed by reversed-phase HPLC with UV/diode-array detection, quantified at 214 nm, and compared against a certified AOD-9604 reference standard. The certificate reports exactly three results: identity, by retention-time and UV-spectral match to the reference standard, with the N-terminal tyrosine contributing a characteristic absorbance near 275-280 nm that reinforces the spectral comparison and helps distinguish AOD-9604 from tyrosine-free substitutes; chromatographic purity, as area percent of the main peak relative to total integrated peak area, which captures reduced, dimeric, and other resolved related forms as impurities rather than as product; and net-peptide assay, as milligrams of peptide per vial.
Every result is issued as a certificate of analysis you — or anyone you forward it to — can verify cryptographically. Reporting identity, purity, and milligram content is the point: a vial can be pure and still underfilled, so we report all three. More on purity vs. net-peptide content and how to read a peptide COA.
Our scope — stated plainly
Testing is RP-HPLC-UV against a certified reference standard. We do not perform mass spectrometry, sterility, endotoxin, heavy-metal, or residual-solvent testing, and the method does not confirm disulfide bond connectivity directly. Because AOD-9604 is a less-common compound, a certified reference standard may need to be sourced before analysis, which can add lead time; we confirm that with you first. KMD Analytical is an independent laboratory and does not sell peptides.
KMD is an independent RP-HPLC-UV lab. We do not run LC-MS / mass-spec, sterility, endotoxin, or heavy-metal testing. If your job needs a capability we don't have, we'll say so.
AOD-9604 testing — FAQ
Can you tell real AOD-9604 from the plain hGH fragment 176-191?
This is one of the cases where RP-HPLC-UV is well suited. The two peptides differ in retention time, so a substitute typically fails to co-elute with a certified AOD-9604 reference standard. On top of that, AOD-9604's N-terminal tyrosine absorbs near 275-280 nm while the unmodified fragment has no such residue, so a tyrosine-free substitute shows no band there — a straightforward spectral discriminator on the diode-array trace. What we still cannot do is confirm the exact molecular mass or sequence of a non-matching sample; that requires LC-MS, which we do not offer.
Can you confirm the disulfide bond is intact?
Not as a direct measurement, and we do not report one. What the chromatogram shows is behavior: the correctly oxidized cyclic monomer, the reduced open-chain form, and disulfide-linked dimers have different reversed-phase retention, so reduced or aggregated material generally resolves as separate peaks and is counted against the area-percent purity figure rather than as main peak. That is strong practical evidence about whether a sample is predominantly the intended form. Proving bond connectivity itself requires mass spectrometry and peptide mapping, which is outside our scope.
My vial is labeled at a high milligram amount. Does that change what I should look at?
It raises the stakes on the net-peptide number. Counterion salt, residual moisture, and bulking agent are a share of powder weight regardless of vial size, so on a high labeled mass the absolute quantity of non-peptide material is correspondingly larger. The assay reports measured peptide milligrams per vial, which is the only figure directly comparable to what the label claims.
Other peptides we test
Retatrutide · Cagrilintide · Tesamorelin · BPC-157 · see the full panel.