An AOD9604 certificate of analysis is a test report for one specific lot. Read it in order. First match the lot identifier to the vial and note the test date. Then check identity by mass near 1815.1 and that the disulfide bond is closed. Next come RP-HPLC purity with the chromatogram, net peptide content and water, then the issuing laboratory.
- AOD9604 is C78H123N23O23S2, average mass near 1815.1, PubChem CID 71300630.
- The two sulfurs are cysteines joined by a disulfide bond that closes part of the chain.
- The reduced open form weighs about two daltons more than the closed form.
- Cysteines can pair between molecules, producing dimers that weigh roughly twice the monomer.
- Dimers are one degradation route the routine panel genuinely does see.
- Reduced and non-reduced analysis together reveal what either alone cannot.
What does an AOD9604 certificate actually certify?
Think of it like a receipt for one specific test. It records what a lab measured on a sample from one lot on one day, so it tells you about that lot and not about every vial ever sold.
It records what a named laboratory measured on a sample drawn from one lot, on one date, by named methods. It is evidence about that sample rather than a warranty about the vial on your bench.
Two documents get confused constantly. A specification sheet lists limits the product is supposed to meet, carries no lot number and no results, and describes an intention. A certificate carries both because it describes an event.
A page with no lot number on its face is the first kind whatever its heading says. For this peptide there is an extra question a certificate should answer, and it concerns a bond rather than a sequence.
- Lot number on the report against the lot number on the vial
- Identity: observed mass against an average near 1815.1
- Disulfide closed, since the reduced form weighs about two more
- Related substances: dimers weigh roughly twice the monomer
- Reduced and non-reduced views compared, where the report carries both
- Net peptide content, counterion and water by Karl Fischer
- Accession number confirmed at the issuing laboratory
What mass should the identity result show?
AOD9604 has the molecular formula C78H123N23O23S2 with an average mass near 1815.1, catalogued as PubChem CID 71300630.
The two sulfur atoms in that formula are the feature worth noticing. They belong to two cysteine residues, and in the finished molecule those two cysteines are joined to each other by a disulfide bond, closing part of the chain into a loop.
So this peptide is not a simple linear chain. It has a defined internal linkage, and whether that linkage is present is a separate question from whether the right residues were assembled.
How does the mass confirm the disulfide is closed?
By two daltons. Forming a disulfide bond removes two hydrogen atoms, one from each cysteine, so the closed form weighs about two less than the open reduced form.
Two daltons on an 1,815-dalton molecule is a small proportional difference and a perfectly resolvable one for a modern instrument. It is not, however, something a reader can check unless the certificate prints the observed mass as a number.
This is the same structural point that applies to cyclic peptides and it arrives differently. The identity result is doing two jobs: confirming the chain and confirming the loop. A certificate saying identity confirmed reports neither.
What is disulfide scrambling?
The wrong cysteines joining together. With two cysteines in one molecule there is only one possible internal pairing, which sounds like it removes the problem. It does not, because the pairing does not have to be internal.
A cysteine in one molecule can bond to a cysteine in another, producing a dimer, and larger aggregates follow from the same chemistry.
The mass tells these apart clearly, since a dimer weighs roughly twice the monomer. Chromatography separates them too, because a dimer is a much larger molecule. This is one degradation route that is genuinely visible to the routine panel, which is worth saying since several others in this catalogue are not.
Worth keeping in proportion: a small amount of dimer is a common finding rather than a sign of a bad batch, and what matters is whether it was measured and reported. A certificate that names a figure has been honest about a routine imperfection. One that is silent has left you unable to tell a clean lot from an unexamined one.
How should the report handle reduced and non-reduced analysis?
Ideally by running both. Analysing the sample as supplied shows what is there. Analysing it again after deliberately reducing the disulfide converts everything to the open form, collapsing dimers back to monomers.
Comparing the two is informative in a way neither alone can be. Material that looks like a single clean peak under both conditions is monomeric with its bond intact. Material that shows a large peak before reduction and a smaller one after has disulfide-linked species in it.
Most research certificates run only the first. That is not a failure and it does mean an entire class of disulfide-related impurity was assessed in one view rather than two.
How do you read the certificate field by field?
Lot number first, against the vial. Then dates, where a test date should follow the fill date and a print date carries no analytical meaning.
Then identity by mass, stated as a number. Disulfide status, whether by the mass itself or by explicit comment. Purity by reversed-phase HPLC with the chromatogram attached. Related substances, meaning dimers and reduced forms. Net peptide content. Counterion. Water. Appearance last.
Each result needs its method beside it. Purity by area percent, by net peptide content and by amino acid analysis are three different numbers for one vial and they do not agree.
What does the purity figure leave out?
Anything that does not absorb at the detection wavelength or does not elute. Reversed-phase purity is an area percentage of what the detector saw.
Peptides are read at 214 nanometres, which responds to the peptide bond and detects peptide impurities well, while salts and water are largely invisible. A vial can be 98 percent pure by area and still be substantially counterion and moisture by weight.
For this peptide there is a specific limitation. The reduced form differs from the closed form by two daltons and a slightly different shape, so whether a separation resolves them depends on the method rather than being guaranteed by it.
What is net peptide content, and why does it change the price?
A synthetic peptide ships as a salt carrying a counterion from purification, plus water absorbed because lyophilised peptide is hygroscopic.
The consequence is arithmetic. A vial labelled 5 milligrams may hold 5 milligrams of powder of which a real fraction is salt and water. Net peptide content of 80 percent means 4 milligrams of peptide, and two suppliers quoting the same price for the same nominal size are not selling the same amount.
Ask which basis the label uses. The cost per milligram comparison ranks the catalogue on one basis so two quotes can be compared honestly.
What do the water and counterion fields tell you?
Water is measured by Karl Fischer titration, which is specific to water. Loss on drying reports everything volatile and reads high when residual solvent is present, so the two numbers are not interchangeable.
Counterion identity is worth reading. Trifluoroacetate is the usual residue of preparative HPLC and is not inert in every experimental context; acetate requires an extra exchange step.
Both feed the net content arithmetic and together explain most of the gap between a high area purity and a lower net peptide figure, which readers frequently mistake for a supplier contradicting itself.
What does the certificate not cover?
Everything after the sample was drawn. Storage temperature, light, how long the vial has been open and how many times it has been entered are all outside it.
The disulfide bond is the specific vulnerability that develops afterwards. Disulfides can exchange and scramble in solution, especially at higher pH, so a lot with a clean single peak at release can carry dimeric material later.
Moisture ingress also quietly makes the net content figure optimistic, because the powder now weighs more per unit of peptide than it did at test.
How do you verify the document is genuine?
Confirm the report at the issuing laboratory rather than with the seller. An independent laboratory issues each certificate against an accession number that resolves on its own site. If the number resolves to a different product, a different lot, or nothing, the document does not describe your material.
Certificates with the verification key removed deserve particular suspicion, and this is not hypothetical in this market. A PDF is easy to edit; a third-party lookup is not.
Lot reports for material supplied here resolve through the certificate verification page, and the sizes carried appear on the AOD9604 product record.
What is the regulatory position?
There is no FDA-approved drug product containing AOD9604 and no United States pharmacopoeial monograph defining what an acceptable batch is. The specification a lot is released against is the supplier's own.
For a disulfide-containing peptide that absence has a concrete cost, because no official standard requires that the bond be confirmed or that dimeric content be limited. Whether either was assessed depends entirely on what the supplier chose to test.
Material described here is supplied for laboratory use only, and nothing in this guide describes use in a person or an animal.
FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. NOT FOR PERSONAL, MEDICAL, DIAGNOSTIC, THERAPEUTIC, OR RECREATIONAL USE.
What is AOD9604 studied for?
Published research on AOD9604 investigates the areas below, which is a different question from what AOD9604 will do for anyone, a claim about a living system that nothing on this site is sold for.
What it is. A man-made peptide matching the tail end of human growth hormone.
What the research looks at. It appears in a limited set of animal and early human studies about that piece of the hormone.
How it is thought to work. A piece of the hormone rather than the whole thing, and it does not carry growth hormone’s full range of effects. The published accounts of how it works are not settled.
What is not established. No approved drug product. Supplier copy routinely credits it with the pharmacology of whole growth hormone, which the primary research does not support.
The full record, including the certificate for the lot in stock, is on the AOD9604 product page.
Common questions
What molecular mass should an AOD9604 certificate show?
How does the mass confirm the disulfide bond?
What is disulfide scrambling?
Why run reduced and non-reduced analysis?
Can the reduced form be told from the closed form on a chromatogram?
More documentation guides
Sources
- PubChem Compound Summary for CID 71300630, AOD-9604. The openable record giving the molecular formula C78H123N23O23S2 and average mass near 1815.1, and showing the two cysteines whose disulfide linkage this page turns on.
- ICH Q2(R2), Validation of Analytical Procedures . Defines specificity, accuracy and precision for identity and assay procedures, and is the basis for requiring that each certificate result names the method that produced it.
- FDA guidance, Q6B Specifications: Test Procedures and Acceptance Criteria. Sets out how disulfide structure, aggregates and reduced forms are specified and tested as attributes distinct from total purity, which is the framework this certificate is read against.
- Finnrick independent verification portal. Third-party lookup used to confirm a certificate resolves to the lot it claims to describe, rather than confirming a document with the seller who supplied it.
