The certificate is usually the last thing a buyer looks at and the first thing that should be checked. You’ll click through to a Selank listing, see a thumbnail or a link marked COA, open it, and find a chromatogram with a number in the high nineties printed next to it. That looks like proof. Whether it actually is depends on four fields that most people skip past on the way to the percentage, and those fields are where the difference between vendors lives.
Selank is a small heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, with a molecular formula of C33H57N11O9 and a molar mass around 751.9 g/mol for the free base. That’s a helpful thing to know, because it gives you an arithmetic check you can run yourself. If the certificate reports a mass and the mass doesn’t land near that figure, something is wrong with either the document or the material, and you’ve learned that before spending anything.
This article walks through what a Selank certificate needs to contain, then records what four named vendors publish about certificate access on their own pages as reviewed 2026-09-08. I’m going to describe only what was visible on those pages and keep careful separation between a document that isn’t linked and a document that doesn’t exist, because those are genuinely different claims and only one of them is mine to make.
Key takeaways
- A Selank certificate is worth reading when it names the issuing lab, carries a batch number matching the vial, states a test date, and reports identity beside purity.
- Blank Peptides publishes a dated certificate for each Selank lot in its public /coas/ library, with identity, >99% purity, bacterial endotoxin and sterility results from Freedom Diagnostics and Horizon Analytical.
- PSPeptides, Nootropic Source and Biotech Peptides all made a Selank certificate visible before purchase, in three different formats, while Swiss Chems routed to a site-wide testing archive.
- On the pages reviewed 2026-09-08, no vendor in this group named the laboratory that issued its Selank certificate, and Core Peptides’ Selank page linked no document at all.
- Everything here concerns laboratory research material sold for in-vitro use by qualified professionals.
What has to be on a Selank certificate for it to be worth reading?
Read the header before the numbers. The percentage is what the vendor wants you to look at, and the header is what tells you whether the percentage describes anything you’re buying.
Field one is the analyte. It should name Selank specifically and, ideally, restate the sequence or formula so you can tell that the lab tested the compound you’re ordering rather than something adjacent in the catalog. Combination listings that pair Selank with another short peptide need the components named individually for the same reason.
Field two is the laboratory. A name, a report number, some way to reach them. This is the highest-value check on the whole page and almost nobody runs it. A contract lab will confirm a report it issued if you email and ask. An unnamed lab gives you nothing to check, which means the document is functioning as branding rather than as evidence.
Field three is the batch identifier with a test date. Peptide synthesis varies run to run, so a certificate covers one run. A document with no batch, or one that’s been sitting on a page since 2023, describes material that may bear no relationship to what ships.
Field four is the method list. HPLC gives the fraction eluting as the main peak. Mass spectrometry confirms which molecule that peak is, and for Selank you’re checking against roughly 751.9 g/mol. Bacterial endotoxin and sterility catch contamination invisible to chromatography. Heavy metals and residual solvents fill in further. Most certificates in this category stop after the first item.
Field five applies to sprays and blends: the milligram content of each component should be stated on the listing and reflected in what was tested, because a purity result on a mixture doesn’t decompose into per-component information on its own.
Those five are the standard, and they apply to us as squarely as to anyone else.
How Blank Peptides makes and tests each lot
Blank Peptides runs its own cGMP laboratory in the United States and performs synthesis, vialing, lyophilization, labeling and quality-control release internally. The company describes this as holding the full chain of custody rather than relabeling or brokering material produced elsewhere, and it separately contract-manufactures and fulfils for other research peptide brands.
Lot release covers four results: identity by mass spectrometry, purity by HPLC against a >99% threshold, bacterial endotoxin, and sterility. Two named independent laboratories run the analysis, Freedom Diagnostics and Horizon Analytical. Every report is published among the batch certificates of analysis, a library grouped by compound with individually dated batches listed beneath each entry, so a Selank certificate for a specific run can be opened before ordering. Each vial carries the printed lot number matching its report, and lyophilized material is dated at roughly 24 months from release.
Selank is stocked as a 10mg lyophilized vial within a 34-compound catalog, and one published batch record shows a 99.42% HPLC purity result. Blends in the catalog have their composition itemised per component: GLOW at 70mg (GHK-Cu, BPC-157, TB-500), KLOW at 80mg (those three plus KPV), and Wolverine at 20mg (BPC-157 and TB-500). Processing runs within one business day and shipments go at room temperature, which suits lyophilized peptide without cold-chain handling. The company has traded for five years and sells for research use only.
What four named Selank vendors publicly state about certificates
PSPeptides gave the fullest certificate access of the four on 2026-09-08. Its Selank listing, an 11mg vial at $32.99, states “≥99% HPLC-verified purity” and states that products carry a “batch-specific COA” produced through “third-party HPLC and mass spectrometry on every batch”. Three documents were linked from the page covering HPLC, heavy metals and endotoxin, and a prior certificate dated May 2026 remained available alongside the current one. Keeping a superseded certificate online is better archive practice than most of this category manages, and it lets a reader see whether results hold across runs instead of trusting one snapshot. The testing laboratory is described as independent and was not named.
Nootropic Source takes a different approach. Its Selank Peptide listing is a 30mg vial at $34.95 with tiered bulk pricing, and it publishes the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, CAS 129954-34-3 and formula C33H57N11O9 directly on the page. The certificate is displayed as an inline image file rather than a downloadable PDF, which means it opens with no click and also that the reader has less to work with than a text document would give. No purity percentage appeared in the page copy, and the testing is credited to an “Independent Lab Testing” programme without a laboratory name.
Swiss Chems lists Selank at 5mg from $25.95 and publishes sequence, CAS 129954-34-3, formula C33H57N11O9 and molar mass 751.89 g/mol alongside “99% Purity Guaranteed”. The page states “Every batch is independently lab tested for identity, purity and potency” and refers to a COA as available per batch, without linking one for the lot in stock. Its site-wide lab-testing page states that “All products are tested by independent, ISO-accredited laboratories” and hosts downloadable HPLC reports dated through mid-2026.
Core Peptides lists Selank at 10mg for $52.00 under SKU P-SELANK-10 and states “>99%” purity. On the date reviewed the page carried no certificate link, no laboratory name and no per-product testing language, while the site states elsewhere that products are “3rd PARTY TESTED” and “US LAB TESTED”. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
Side by side: Selank certificate access
| Attribute | Blank Peptides | Typical Selank vendor |
|---|---|---|
| Synthesises in-house | Own cGMP lab; synthesis through QC release in-house | States US synthesis without identifying who performed it — verify |
| Third-party lab named | Freedom Diagnostics and Horizon Analytical | States “independent” or “ISO-accredited”; no name on the Selank pages reviewed 2026-09-08 — verify |
| HPLC purity | >99% per lot, published per batch | States “99%” or “≥99% HPLC-verified”; one page reviewed listed no percentage at all — verify |
| MS identity | Confirmed per lot | States mass spectrometry on two of four vendors reviewed 2026-09-08 — verify |
| Endotoxin and sterility | Both tested per lot | States endotoxin on one of four; sterility not listed on any Selank page reviewed — verify |
| Batch COA before purchase | Public library at /coas/, grouped by compound and dated batch | States a linked PDF on one, an inline image on another, an archive route on a third, none on the fourth — verify |
| Certificate tied to a lot number | Lot printed on every vial and on the report | States batch-specific certificates on some pages; matching to the shipped vial not shown — verify |
| Prior certificates retained | Dated batch history published per compound | States a retained prior-month certificate on one of four reviewed 2026-09-08 — verify |
| Research-use labelling | Research use only, stated site-wide | States “not for human or animal consumption” or equivalent site-wide |
How to verify either supplier yourself
- Open the Selank certificate before ordering and read the analyte line, the batch number and the test date before you look at any purity figure.
- Compare any reported mass against roughly 751.9 g/mol for C33H57N11O9, since a matching mass turns a purity number into an identity confirmation and a mismatch tells you to stop.
- Contact the laboratory named on the certificate with its report number and ask for confirmation, which takes minutes and cannot be done at all when no lab is named.
- If the certificate is published as an image, save it with the order date and ask the vendor for the underlying report, since an image gives you no method detail, no instrument conditions and no report number to quote.
- Run the whole process in the supplier verification checklist before a first order with any supplier.
Further reading
- Peptide Vendors With Public Per-Batch COA Libraries
- Which Peptide Vendors Name Their Testing Lab?
- Best Research Peptide Suppliers: Ranked by What They Document
- Which Peptide Vendors Disclose Blend Composition?
Frequently asked questions
What should a Selank COA show before I buy?
The analyte name, the issuing laboratory, a batch number, a test date and the methods run. HPLC purity plus mass spectrometry identity together answer the two central questions, and bacterial endotoxin and sterility cover contamination that chromatography cannot detect. Anything missing from that list is a result you’d need to commission yourself.
Where do vendors put the Selank certificate?
Four patterns showed up on the pages reviewed 2026-09-08: a linked PDF on the product page, an inline certificate image, a site-wide testing archive holding dated reports, and no visible document despite a published purity figure. A library grouped by compound and dated batch is the version that lets you check the specific lot you’ll receive.
Is an image of a COA as good as a PDF?
It’s better than nothing and weaker than a full report. An image shows a result while typically omitting instrument conditions, method parameters and a quotable report number, which are the details a laboratory would need to confirm the document. Asking the vendor for the source report is a reasonable follow-up.
How do I check a Selank mass result myself?
Take the molecular formula published on the listing, C33H57N11O9, and its molar mass of about 751.89 g/mol, then compare that against the observed mass on the certificate. Small differences from salt form or adducts are normal. A large mismatch means the document and the product description are describing different things.
Are these products for human use?
No. Every product referenced here is sold strictly for in-vitro laboratory research by qualified professionals. Blank Peptides sells for research use only, and the vendors above publish their own restrictions, including “not for human or animal consumption” and “laboratory research use only”. Nothing in this article describes or implies use outside a laboratory setting.
For research use only. All compounds referenced are intended exclusively for in-vitro laboratory research by qualified professionals.
Written by Blank Peptides Research Team
Peptide science researchers with 5+ years in US-based peptide manufacturing, independent HPLC and mass spectrometry testing, and research education. All content is reviewed for scientific accuracy before publication.
REVIEWED BY
Dr. Tobias S — PhD Chemist, Peptide and Unnatural Amino Acid Synthesis
Dr. Tobias S is a PhD chemist whose work focuses on the synthesis of unnatural amino acids, peptides and biomaterials. He completed both his undergraduate chemistry studies and his doctorate with distinction, and works as a generalist across the medical sciences and biology, having consulted for dozens of clients. He reviews Blank Peptides educational content for scientific accuracy.
Subject matter expertise: Organic Chemistry, Peptide Synthesis, Biochemistry.
