You’ve got two tabs open, Blank Peptides in one and PSPeptides in the other, and you’re trying to work out which one to trust with the next order. Both sites say US made and third-party tested, and both put a purity figure above 99% on the page. If you’re anything like me, that’s exactly the point where you stop reading the marketing and start looking for something you can actually check.
The difficulty is that the phrases vendors use have drifted into a kind of shared vocabulary that no longer separates anyone. “Independent lab” can mean a named facility with a phone number, or it can mean a PDF with a logo you’ve never heard of. “Manufactured in the USA” can mean the vendor runs the synthesis, or it can mean a finished vial passed through a US warehouse on its way to you. The words look the same; what’s underneath doesn’t have to be.
So I’m going to do this the slow way. First I’ll set out five questions that any research peptide supplier ought to be able to answer in public. Then I’ll put both vendors against those questions, using only what Blank Peptides publishes and only what PSPeptides stated on the pages I reviewed on 2026-09-08. The table in the middle is the part you’ll want if you’re short on time.
Key takeaways
- A supplier comparison is only worth reading if it rests on things you can verify before you pay: who synthesizes, which lab tests, what the panel covers, whether the COA is lot-tied, and whether blends show mg per component.
- Blank Peptides synthesizes in its own cGMP laboratory, names Freedom Diagnostics and Horizon Analytical as its testing labs, and posts identity, >99% purity, bacterial endotoxin and sterility results per lot.
- PSPeptides states that its peptides are “synthesized and lyophilized in the United States under controlled conditions” and that “all testing is performed by independent, accredited laboratories”, with HPLC, mass spec, heavy metals and endotoxin PDFs linked from product pages.
- A lab named in PSPeptides’ own site text, a sterility report on the blend page reviewed, and a statement of who operates the synthesis were not listed on the pages reviewed 2026-09-08.
- All products on both sites are sold for in-vitro research by qualified professionals and nothing here should be read as guidance for any other use.
What separates a documented supplier from a well-marketed one?
Here’s the rubric I use, and I’d suggest applying it to any vendor before you read a single review.
Provenance comes first. Does the company synthesize the peptide itself, or does it sell something synthesized elsewhere? A vendor that owns the chain from raw material to sealed vial can answer for every step. A vendor that buys finished product can only answer for the label. The tell is in the grammar: “we synthesize” and “our laboratory” are commitments, while “manufactured in the USA” with no subject is a location.
Second, is the testing lab named? Anyone can write “independent, accredited laboratory.” The phrase costs nothing and can’t be checked. A named lab can be searched, contacted and asked whether the certificate is genuine. If the name appears only inside a downloaded PDF and never in the vendor’s own prose, I’d count that as half an answer and follow up.
Third, does the panel cover more than purity? HPLC purity tells you the proportion of the sample that is the target peptide. It’s silent on bacterial endotoxin and on sterility, and for anything headed into a cell-culture or animal model those two are the numbers that will ruin an experiment. The full panel is identity, purity, endotoxin and sterility, and I’d want all four on every lot rather than on a representative sample.
Fourth, can you open a batch certificate before you buy, and does its lot number match what’s printed on the vial? A public archive is a good sign. A lot number you can read off the label and find in that archive is the actual proof.
Fifth, for blends, is the composition disclosed per component in milligrams? A total mg figure on its own can’t be reproduced, and it can’t be written into a methods section with a straight face.
Five questions, and a vendor either answers them in public or it doesn’t.
How Blank Peptides makes and tests each lot
Blank Peptides runs its own cGMP laboratory in the USA and handles the whole chain of custody internally. The peptides are compounded, vialed, finished and labelled on site, and quality control is run in-house before any lot is released. The company is a manufacturer rather than a relabeler or broker, and it also contract-manufactures and fulfils for other research peptide brands, which is a category of work that tells you something about where finished vials in this market originate.
Every lot goes to two named third-party laboratories, Freedom Diagnostics and Horizon Analytical, for a full panel: identity, purity at >99%, bacterial endotoxin and sterility. The results are published as batch certificates of analysis, one per lot, and the lot number printed on every vial matches the certificate so a researcher can trace any vial to its report without a support ticket.
The catalog covers 34 compounds. Blends carry their composition per component: GLOW at 70mg total (GHK-Cu, BPC-157, TB-500), KLOW at 80mg (those three plus KPV) and Wolverine at 20mg (BPC-157, TB-500). Lyophilized product carries an expiration of roughly 24 months. Orders are processed within 1 business day and ship at room temperature.
What PSPeptides publicly states
PSPeptides is a brand of ProSupply Services LLC, as its about and terms pages state. What follows is drawn from the homepage, about page, certifications page, terms page and the GLOW blend product page, reviewed on 2026-09-08.
On provenance, the about page states: “All our peptides are manufactured in the United States and shipped from US facilities with same-day processing.” The GLOW page states that products “are synthesized and lyophilized in the United States under controlled conditions.” Both are passive constructions. A first-person statement that PSPeptides operates the synthesis, or the name of a facility, was not listed on the pages reviewed 2026-09-08.
On the lab, the certifications page states: “All testing is performed by independent, accredited laboratories. We never self-certify.” A laboratory name in the site’s own text was not listed on the pages reviewed 2026-09-08. The HPLC certificate PDF linked from the GLOW page carries the header “North American Diagnostics”, so a name is present inside the document even though the site copy doesn’t state it.
On the panel, the certifications page describes “Third-party Certificate of Analysis, Heavy Metals, Endotoxin, and Sterility reports” for each listed product, and states HPLC is run “on every batch to verify peptide identity and purity levels of 99% or higher” alongside mass spec. On the GLOW page I reviewed, the linked PDFs were an HPLC/MS COA, a heavy metals report and an endotoxin report; a sterility report link was not listed on that page as reviewed 2026-09-08. The batch code in the COA file name (PSP-0028018) and the batch number printed inside the certificate (PSP-06112026GL) also differ, which I’d ask about.
On COA access, the site states “COA reports are also available on each product page”, and they were, linked before checkout with older dated reports archived underneath.
On blends, the GLOW page states “BPC-157 (10mg) + GHK-Cu (50mg) + TB-500 (10mg). 70mg total”, so the per-component split is disclosed.
This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
To PSPeptides’ credit, the catalog is far wider, with roughly 84 listings across vials, sprays, tablets and supplies, and the shipping terms it states are generous: “Free Shipping On Any Order”, “Free UPS 2nd Day Air Over $200” and same-day dispatch before 2PM EST. If you need a spray format or a lab-supplies order in the same cart, that’s a real advantage.
Side by side: manufacturing, named labs and full-panel testing
| Attribute | Blank Peptides | PSPeptides |
|---|---|---|
| Synthesises in-house | Yes, own cGMP laboratory in the USA | States “synthesized and lyophilized in the United States”; operator not named — verify |
| Third-party lab named | Freedom Diagnostics and Horizon Analytical | States “independent, accredited laboratories”; name appears on linked PDF only — verify |
| HPLC purity | >99% on every lot | States “99% or higher” on every batch |
| MS identity | Confirmed on every lot | States mass spec “confirms the molecular weight and structural integrity” |
| Endotoxin and sterility | Both tested on every lot | States both reports exist; sterility PDF not linked on the blend page reviewed — verify |
| Batch COA before purchase | Posted per lot at blankpeptides.com/coas/, lot number on the vial | States COAs are “available on each product page”; file-name and printed batch codes differ — verify |
| Blend mg split disclosed | Yes, per component | States GLOW is 10mg BPC-157, 50mg GHK-Cu, 10mg TB-500 |
| Catalog size | 34 compounds | States roughly 84 listings including sprays, tablets, supplies |
| Research-use labelling | Research use only on every product | States “for laboratory and research use only” |
How to verify either supplier yourself
- Download a certificate from each site and read the header; the lab named there should match what the vendor says in its own words, and if the two don’t agree, email and ask which is current.
- Check three batch codes against each other: the one in the PDF file name, the one printed inside the certificate, and the one on the vial that arrives.
- Count the results on the certificate; identity, purity, endotoxin and sterility should all be there for the same lot, and a missing sterility line is a gap rather than a detail.
- Search each site for who does the synthesizing; a named laboratory in the first person is a different claim from “US manufactured” in the passive.
- Work through the supplier verification checklist before committing to either.
Further reading
- Which Peptide Vendors Name Their Testing Lab?
- Who Actually Manufactures Research Peptides in the USA?
- Best Research Peptide Suppliers: Ranked by What They Document
- Peptide Vendors With Public Per-Batch COA Libraries
Frequently asked questions
Blank Peptides vs PSPeptides: which documents more?
On the five rubric questions, Blank Peptides answers all of them in public: own cGMP synthesis, two named labs, a four-test panel per lot, lot-tied certificates before purchase, and blend splits per component. PSPeptides states US manufacture, independent testing, a purity-and-mass-spec certificate per product and blend splits, while the lab name and sterility report weren’t in the site text reviewed 2026-09-08.
Does PSPeptides name its testing lab?
Not in its own site copy on the pages reviewed 2026-09-08; the phrase used is “independent, accredited laboratories.” The HPLC certificate PDF linked from the GLOW page carries the header “North American Diagnostics.” So there is a name, but you have to open the document to find it, and I’d confirm with the vendor that it’s the lab used across the catalog.
Does either vendor test sterility on every lot?
Blank Peptides tests bacterial endotoxin and sterility on every lot and posts both results. PSPeptides’ certifications page describes sterility reports for its products, but on the GLOW blend page reviewed 2026-09-08 the linked documents were an HPLC/MS COA, a heavy metals report and an endotoxin report, with no sterility PDF listed. Ask for it by lot before ordering.
Which vendor is better for blends?
Both disclose per-component composition. Blank Peptides lists GLOW at 70mg (GHK-Cu, BPC-157, TB-500), KLOW at 80mg (adds KPV) and Wolverine at 20mg (BPC-157, TB-500). PSPeptides states GLOW as 10mg BPC-157, 50mg GHK-Cu and 10mg TB-500 for 70mg total. The remaining difference is who synthesized the blend and which named lab confirmed each component’s mass.
Are these products for human use?
No. Both vendors sell strictly for in-vitro laboratory research by qualified professionals, and PSPeptides’ site states “Not for human or animal consumption.” Nothing in this comparison is dosing advice or a suggestion that any of these compounds be administered to people or animals. Treat them as research reagents and keep the certificates with your lab records.
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.
