NN9535 is one of the most widely manufactured compounds in this category, which is good for availability and means more variation in who is selling it and what they can document. The molecule does not vary between suppliers. The paperwork behind a given vial does, substantially.
That makes documentation the main axis of comparison rather than price, because a price difference on a widely supplied material usually reflects a difference in what was tested rather than a difference in efficiency.
Structurally, what you are buying
A synthetic peptide engaging a single incretin receptor, built on a backbone related to a naturally occurring incretin sequence, with substitutions that change receptor engagement and resistance to the enzymes that would otherwise clear it quickly.
It also carries a fatty-acid chain attached to the backbone, which binds albumin and extends how long the molecule circulates. That modification is the handling story rather than the pharmacology story, and NN9535, LY3298176 and LY3437943 compared sets out how the three differ.
The NN9535 sequence written out
In one-letter code, with Aib standing for α-aminoisobutyric acid, the 31 residues run H-Aib-E-G-T-F-T-S-D-V-S-S-Y-L-E-G-Q-A-A-K-E-F-I-A-W-L-V-R-G-R-G, where the leading H is histidine, ending in a free C-terminal acid. That is the backbone read from the systematic chemical name in PubChem CID 56843331, a record that carries the name NN9535 and the CAS number 910463-68-2; the record gives a systematic name rather than letter code, so the letters here are a transcription of it.
The 2015 paper describing its discovery (Lau and colleagues) gives the modifications in words: two amino acid substitutions compared with human GLP-1, Aib at position 8 and Arg at position 34, and a derivatised lysine at position 26. Those numbers follow the numbering of human GLP-1, not a count from the start of this chain. Counting along the 31 residues above, the Aib is residue 2, the lysine (there is one in the sequence) is residue 20 and the arginine is residue 28, the first of the two, each six lower than the paper's number. That is how the catalogue record can say Aib at position 2 and Lys26 in the same line.
What sits on that lysine is spelled out in the same PubChem name. Attached to its side-chain amine are two aminoethoxy-ethoxy-acetyl linker units, then a glutamic acid joined through its side-chain carboxyl, then an 18-carbon diacid (octadecanedioic acid). The catalogue record abbreviates this as γGlu-(AEEA)2-C18 diacid.
For the identity line this means the expected mass is not the mass of 31 ordinary amino acids. C187H291N45O59 is the formula of the whole molecule in the PubChem record: the Aib residue and the lysine side chain, with its linker units, glutamic acid and fatty diacid, are all inside it. An observed mass that reconciles with the expected figure is therefore consistent with the modified molecule as a whole, and a figure worked out from the bare peptide chain would not match it. What an intact mass does not show is the order of the residues: the same residues in a different order would have the identical formula and monoisotopic mass.
The differences that actually matter
| Difference | Strong | Weak |
|---|---|---|
| Certificate scope | Names the lot on your vial | Covers the product line |
| Identity method | Fragments the molecule, reads a sequence | Weighs the intact molecule only |
| Testing laboratory | Named, contactable, accredited | Third-party tested, unnamed |
| Salt form | Stated without being asked | Unknown to the seller |
| Endotoxin | Reported against a stated limit | Absent from the panel |
The molecule is identical across suppliers. These five are where they differ, and all are checkable before ordering.
Comparing suppliers on documentation turns those five into a scoring method that needs one email and about fifteen minutes. Endotoxin testing covers what the last of the five reports and what a stated limit means.
Reading the certificate
In the usual order. The lot number against the vial first, because if those differ nothing else on the page describes your material. Then the two dates, which must run forwards, and whose gap tells you something about which tests were actually run.
Then identity with its method named, then content, then purity with its method and detection wavelength named. A result without a method is a number rather than a measurement, and scanning for results that carry no method is the fastest completeness check available.
Reading a certificate of analysis line by line goes through every field, and what a certificate does not test for covers the absences that are normal.
For NN9535 specifically, these are the identifiers a quote or certificate should reconcile with, set out from the two records this guide draws on: the catalogue record and PubChem CID 56843331.
| Identifier | Catalogue record | PubChem record | Set it against |
|---|---|---|---|
| CAS number | 910463-68-2 | 910463-68-2 | The CAS number on the quote and certificate |
| Molecular formula | C187H291N45O59 | C187H291N45O59 | The formula, where the certificate prints one |
| Average molecular weight | 4113.58 g/mol | 4114 g/mol | An observed mass stated as average |
| Monoisotopic mass | Not listed | 4111.12 | An observed mass stated as monoisotopic |
The two average figures agree: PubChem prints four significant figures, and 4113.58 rounds to 4114. The monoisotopic figure is about 2.5 lower than the average.
Content, and the number that belongs in a calculation
The measured content on the certificate, not the strength on the label. Fills are set to meet or exceed the nominal figure, so the measured number is typically a few percent higher, and using the label builds that difference into everything downstream.
The powder itself weighs more than either figure, because it includes counter-ion and residual water. That is not a discrepancy, because the content assay measures peptide rather than powder. Net peptide content covers the distinction.
Choosing a strength
NN9535 is supplied across five strengths. Larger vials are cheaper per milligram and that saving is only realised if the vial is finished before the material ages out, so the sizing question is consumption rather than unit price.
On a first order from an unfamiliar supplier, buy the smallest. The purpose of a first order is to establish whether the certificate arrives without chasing, names the right lot and comes from a named laboratory, and none of that requires quantity.
Reconstitution and handling
The acyl chain that extends circulation also makes this molecule more hydrophobic than its residue composition suggests, which is why this class is slow to dissolve. Slow is expected rather than a fault.
Shaking drives air into a solution, and the air-water interface is where peptides unfold and associate, which is why foaming is read as a sign of stress on the material. Why some peptides resist dissolving covers the mechanism.
Dry and sealed, the material is comparatively robust. Once reconstituted, both elapsed time and the number of entries into the vial matter, which freeze-thaw cycles and aliquoting and vial closures cover.
What varies legitimately between lots
Content within the fill tolerance, purity within a narrow band, and retention time within a small range characteristic of the compound rather than the batch. All three moving slightly is ordinary.
Identity and the calculated mass should not move at all. For NN9535 the identity mass on every lot's certificate should reconcile with 4113.58 g/mol, the molecular weight in the catalogue record for the 31-residue molecule (formula C187H291N45O59), and the certificate should state which basis its observed mass is on before the two numbers are compared; molecular weight covers the two conventions. A change in either, with the method unchanged, is a question rather than variation. Lot-to-lot consistency separates what varies because the material varies from what varies because the reporting changed.
Why a cheap quote is usually explained
Three explanations cover almost all of it: a lower purity specification, a certificate that is not lot-matched, or bulk material repackaged without lot-level records. None is necessarily wrong and each is a difference in the product rather than a better price for the same product.
What research peptides cost covers where the money goes upstream, which is useful context for judging whether a quote is implausible.
Before placing a first order
- Ask for the certificate matching a specific lot you would receive.
- Ask which laboratory issued it and what that laboratory is accredited for.
- Ask whether the identity mass on the certificate is stated as an average or a monoisotopic value: for NN9535 the two expected figures are 4113.58 and 4111.12, about 2.5 apart.
- Ask which salt form is supplied, since it rarely appears on the document.
- Ask the lead time for in-stock versus made-to-order, because those are different numbers.
- Ask what happens if a lot is withdrawn after delivery.
Auditing a peptide supplier is the longer checklist, and how the answers arrive is evidence in its own right alongside what they say.
Scope
NN9535 is supplied here strictly for laboratory research. Nothing in this guide describes effects in any organism, and nothing on a certificate speaks to them. What documentation settles is what the material is, how pure it is, how much of it there is, and whether the lot in front of you is the one the document describes.
In short
One widely made molecule, five strengths, and suppliers who differ almost entirely in what they can document. Settle the paperwork first, buy the smallest strength to test a new supplier, use the certificate content figure rather than the label, and expect slow dissolution.
Planning resupply
Lead times in this category are long and variable enough that reactive ordering produces either a gap in the work or an emergency purchase at a worse price. Measure consumption for a quarter and set a reorder point from the measurement rather than from memory.
The constraint specific to research material is that it degrades while it waits, so holding more stock buys exposure rather than security beyond a point. There is a ceiling as well as a floor, and the ceiling is whatever can be used inside the usable window. Inventory levels and reorder points covers deriving both.
What to record once it arrives
- The lot, read in full from the vial rather than from the packing slip, with the strength recorded alongside it, because a compound supplied across five strengths produces records where the lot alone does not tell a later reader how much peptide was in the vial.
- The certificate, downloaded and stored with your own purchase records rather than kept as a link to the supplier archive, because archives move and documents are superseded when a lot is replaced.
- The measured content figure, which is the number every later calculation uses.
- The salt form, which exists only in correspondence unless written down.
- Reconstitution date, solvent, measured volume and the resulting concentration.
Lot traceability and recordkeeping covers why the lot number is the field everything else hangs off, and records to keep covers how the pieces tie together.
On arrival
Check the lot on every vial against the certificate supplied for it, reading the full string rather than the last few characters. Lot numbers within a supplier range frequently differ only in their final digits, and a mismatch found at receiving is a conversation while the same mismatch found later is an unanswerable question.
Inspect the cake. A collapsed, shrunken or glassy cake is a finding worth raising, though it says nothing about identity or purity, which are separate questions the certificate answers. Receiving and inspecting a peptide shipment is the ten-minute protocol.
Where this sits
For the class as a whole, GLP-1 and incretin peptides covers what the category actually is. For the wider buying process, the wholesale buying guide covers evaluating a supplier and opening an account.
Comparing two quotes fairly
Normalise before dividing. Put both quotes on the strength you will actually use (NN9535 is listed here at 5, 10, 20, 30 and 50 mg), add shipping, add the cost of money for the terms offered, and only then compare. Thirty-day terms are worth something, but less than they look: at a 12% annual cost of money, thirty days is worth about 1% of the invoice, so a quote on terms has to sit within roughly that margin of a prepayment quote to come out ahead.
Where two quotes differ on documentation, treat documentation as a gate rather than a score: decide the minimum you will accept, exclude anyone below it, and compare on price only among those who pass. That keeps the cheap-but-untraceable option out of the comparison entirely.
A note on bundles and blends
Where this compound appears inside a bundle or a combination product (this catalogue lists AM833/NN9535, a AM833 and NN9535 blend, at 5 mg / 5 mg), each vial still carries its own lot and should still be traceable to a certificate naming that lot. A bundle supplying one document for several lots has not met that bar, and checking the lot count against the certificate count takes seconds.
On a blend certificate the content line usually reports one component rather than the vial total, so a figure that looks low is often correct. Blends and single vials covers the reading.
A closing check
Before the second order, review what the first one taught you. Did the certificate arrive without chasing, did it name the right lot, did the material arrive as promised, and did a technical question get an answer from someone who could see the document. Those four answers are better evidence than any pre-order diligence.
This is one part of buying wholesale. The wholesale buying guide covers the whole process from evaluating a supplier to placing a first order.