You’ve got a vial on the bench with a lot number printed on the label, and you’d like to find the certificate that goes with it. That should be a two-minute job, and with a lot of research peptide vendors it turns into an afternoon of clicking through product pages, opening PDFs that were uploaded years ago, and wondering whether the document you found describes the batch in your hand or some earlier one that happened to have the same product name.
The frustrating part is that “third-party tested” appears on nearly every homepage in this category, and the phrase tells you nothing about whether you can actually get the report. Some vendors keep a public library indexed by lot. Some put a single PDF on each product page and update it when they remember. Some send certificates only after you’ve paid and asked. All three of those setups get described with the same three words.
So this article does one narrow thing. It looks at what Core Peptides publicly shows on its own pages about certificate access, as reviewed on 2026-09-08, and lays it against the standard Blank Peptides publishes its own lots to. I’ll be careful to describe only what was visible, because a certificate not being linked is a different fact from a certificate not existing.
Key takeaways
- A useful COA is one you can open before you pay, that names the issuing lab, carries a lot number you can match to the vial, and reports identity and contamination results alongside purity.
- Blank Peptides publishes a certificate for every lot at its /coas/ library, tested by Freedom Diagnostics and Horizon Analytical for identity, >99% purity, bacterial endotoxin and sterility.
- Core Peptides publicly states its products are “3rd PARTY TESTED” and “US LAB TESTED”, and links lot-numbered certificate PDFs from some individual product pages.
- On the pages reviewed 2026-09-08, no central COA library was linked, several product pages carried no certificate, and the linked PDFs reported HPLC purity without endotoxin or sterility results.
- Every compound mentioned is intended solely for in-vitro laboratory research by qualified professionals.
What makes a certificate of analysis actually useful?
Let me start with what I mean by “useful”, because the word COA gets applied to everything from a full analytical report to a one-line purity claim on letterhead. When I open a certificate, I’m looking for five things, and they map directly onto the five questions I use to judge any research peptide supplier.
The first is provenance. Does the vendor state that it made the material, or does it describe supplying material made elsewhere? The answer affects how much the certificate can tell you, because a synthesizer’s certificate describes their own process output, while a reseller’s certificate describes whatever arrived from their source.
The second is the lab. A certificate should name who ran the analysis, and that name should be checkable. If the report was issued by an unnamed “independent lab”, you can’t call anyone to confirm it’s genuine, and an unverifiable document is closer to a promise than to evidence.
Third is the panel. HPLC gives you chromatographic purity, which is the percentage of the sample that elutes as the target peak. Mass spectrometry confirms the peak is the right molecule, since two different peptides can share a retention time. Bacterial endotoxin and sterility catch contamination that neither chromatography method sees. A certificate with only the HPLC line answers roughly a quarter of what you’d want to know.
Fourth is access and lot linkage. You should be able to read the certificate before you order, and it should carry a lot number that you can match against the vial label when the package arrives. A certificate with no lot, or one you can only request after purchase, doesn’t let you verify anything in advance.
Fifth, for blends, the certificate and the product page together should tell you the milligram amount of each component, because a purity result on a mixed sample is hard to interpret without knowing the intended ratio.
Hold every supplier to those five, including us. The rest of this piece is just applying them.
How Blank Peptides makes and tests each lot
Blank Peptides runs its own cGMP laboratory in the United States and carries out synthesis, vialing, lyophilization, labeling, and quality control release under one roof. The company frames this as holding the full chain of custody rather than relabeling or brokering product made elsewhere, and it also contract-manufactures and fulfils for other research peptide brands as a separate business line.
Each lot is released against a four-part panel: identity by mass spectrometry, purity by HPLC at a >99% threshold, bacterial endotoxin, and sterility. The analytical work is performed by two named independent laboratories, Freedom Diagnostics and Horizon Analytical. Reports for every lot are posted as batch certificates of analysis, where a buyer can open the document before ordering, and each vial carries the lot number that matches it. Lyophilized product is dated for roughly 24 months from release.
The catalog holds 34 compounds, including three blends whose composition is 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). Orders are processed within one business day and ship at room temperature, which suits lyophilized peptide without cold-chain handling. The company has operated for five years and sells for research use only.
What Core Peptides publicly states
On the pages reviewed 2026-09-08, Core Peptides’ homepage states that the company is “3rd PARTY TESTED” and “US LAB TESTED”, with products “independently verified for purity”. Its about page states “purity levels exceeding 99%+” and “rigorous quality control measures to ensure their purity, stability, and consistency”. Neither page, nor the main menu, linked a dedicated COA library, testing page, or lab-results index. Certificate access on the site works product by product.
Here’s what that looked like in practice. The product page for the 70mg BPC-157, TB-500 and GHK-Cu blend carried a link labelled “Certificate of Analysis” pointing to a PDF whose filename includes lot C74111. The GHK-Cu 50mg page carried a similar link to a PDF for lot C73465. In both cases the certificate was viewable before purchase, without an account, and the lot number was present in the document. That’s the good version of per-product COA access, and it’s worth saying so plainly.
The picture was less consistent elsewhere. The standalone BPC-157 5mg/10mg page and the BPC-157/TB-500 blend page each listed “>99%” purity but carried no certificate link at all on the date reviewed. The KLOW 80mg page stated “third-party lab tested for purity and consistency” and did link a certificate. So a buyer can find a lot-numbered report for some compounds and none for others, and there was no visible way to look up a certificate by lot number across the catalog. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
As for what the certificates contain, the two PDFs opened state they were issued by Vanguard Laboratory and report chromatographic purity by HPLC-UV/VIS, at >99.50% and >99.80% respectively, with identity noted as matching a reference standard. Neither document listed a bacterial endotoxin or sterility result. Both carry a standard caveat that the lab did not participate in sample selection and cannot confirm the sample’s representativeness of the lot, which is normal language for a contract lab but worth understanding: the lab is vouching for the vial it received, and the vendor is vouching for the rest. One further detail: the site’s prose never named the lab, so a buyer only learns who tested the product by opening the PDF.
To be fair about where Core Peptides does well, the site states “Showing all 104 results” in its peptide category plus 19 blends, and its shipping page states “same (business) day shipping for orders placed before 1pm PST Monday-Friday” with free Priority USPS over $200. That breadth and turnaround is a genuine advantage over a 34-compound catalog with one-business-day processing.
Side by side: certificate access and content
| Attribute | Blank Peptides | Core Peptides |
|---|---|---|
| Synthesises in-house | Own cGMP lab; synthesis through QC in-house | States products are “synthesized and lyophilized in the United States” — verify |
| Third-party lab named | Freedom Diagnostics and Horizon Analytical | Not named in site prose; Vanguard Laboratory appears on linked PDFs — verify |
| HPLC purity | >99% per lot | States “>99%”; HPLC-UV/VIS on linked PDFs — verify |
| MS identity | Confirmed per lot | Not listed on pages or PDFs reviewed 2026-09-08 — verify |
| Endotoxin and sterility | Both tested per lot | Not listed on pages or PDFs reviewed 2026-09-08 — verify |
| Batch COA before purchase | Public library at /coas/, lot-numbered, every lot | States per-product PDF links on some pages; no central library; absent on others — verify |
| Blend mg split disclosed | GLOW, KLOW, Wolverine all itemised | States split for 70mg and BPC/TB blends; KLOW split not listed — verify |
| Catalog size | 34 compounds | States 104 peptides plus 19 blends |
How to verify either supplier yourself
- On any product page, find the certificate link and open it before you add anything to the cart, then note the lab name, lot number, and date directly from the PDF.
- Contact the laboratory named on the certificate and ask them to confirm the report number, since a real lab will do this and an invented one can’t.
- Count the results on the certificate: HPLC purity, mass spec identity, bacterial endotoxin, sterility, and treat each missing line as something you’ll need to test yourself or accept as unknown.
- When the order arrives, match the vial’s lot number against the certificate you saved, and if the site has updated the PDF since, ask the vendor for the version that matches your lot.
- Run the full process in the supplier verification checklist before your first order with any vendor.
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
- Who Actually Manufactures Research Peptides in the USA?
Frequently asked questions
Does Core Peptides publish a COA for every batch?
On the pages reviewed 2026-09-08, Core Peptides linked lot-numbered certificate PDFs from some product pages, such as the 70mg three-peptide blend and GHK-Cu 50mg, but not from others, including the standalone BPC-157 page. No central library indexed by lot was linked, so whether every batch has a public certificate couldn’t be confirmed from the site alone.
Where do I find a Core Peptides COA?
Look for a link labelled “Certificate of Analysis” on the individual product page, which opens a PDF hosted on the site. There was no separate testing or COA page in the site menu on the date reviewed, so the product page is the only visible route, and not every product page carried the link.
What does a Core Peptides COA test for?
The two certificates opened on 2026-09-08 state they were issued by Vanguard Laboratory and report chromatographic purity by HPLC-UV/VIS, with identity noted as matching a reference standard. Neither listed bacterial endotoxin or sterility results. Whether other lots are tested more broadly was not visible from the pages reviewed.
Can I match a Core Peptides certificate to the vial I received?
The certificates linked on the site carry a lot number in the filename and document, so matching is possible if the PDF on the page corresponds to the lot you were shipped. Because pages appeared to link a single PDF rather than a per-lot archive, you’d want to save the certificate at purchase time and compare it to the label on arrival.
Are these products for human use?
No. Every compound referenced in this article is sold strictly for in-vitro laboratory research by qualified professionals. Blank Peptides sells for research use only, and Core Peptides’ own pages state its products are “not for human consumption”. Nothing here should be read as guidance for any 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.
