You’ve got two tabs open. One is Blank Peptides, the other is Neurolabs, and both are telling you their material is above 99% pure and tested by a third party. The prices are in the same neighborhood, the product lists overlap on the compounds you actually need, and you’re trying to work out whether there’s a real difference underneath the marketing or whether you should just pick the one with the faster checkout.
I get the frustration, because the surface of these two sites really does look similar. And to be fair to both, they’re closer on documentation than most pairs of peptide vendors I’ve compared. But there are differences, and they show up in exactly the places that matter for a research order: who made the material, whether the sterility of a vial was tested or inferred, and whether a blend tells you what’s in it in milligrams.
What follows is a head-to-head built entirely on what each company publishes. Reputation, price, and packaging stay out of it. I’m putting the two sites next to each other on five documentation questions, and the table in the middle of this piece is the part I’d bookmark.
Key takeaways
- A supplier comparison is only as good as the documents behind it, so the five things to compare are provenance, whether the testing lab is named, whether the panel goes beyond purity, whether a lot-tied COA is open before purchase, and whether blend composition is disclosed per component.
- Blank Peptides synthesizes, vials, and finishes in its own cGMP laboratory and tests every lot for identity, >99% purity, bacterial endotoxin, and sterility through Freedom Diagnostics and Horizon Analytical, with a published batch COA per lot.
- Neurolabs publicly states that it sources from vetted manufacturers within the United States, that Freedom Diagnostics screens each lot across six methods including LC-MS identity, HPLC-UV purity, and LAL endotoxin, and that its COAs are viewable on its site.
- On the pages reviewed 2026-09-08, Neurolabs did not state that it synthesizes its own peptides, did not list a sterility test by name, and did not list per-component milligram amounts for its GLOW and KLOW blends.
- Both suppliers label their products for in-vitro laboratory research only, and nothing in either company’s documentation changes that.
What are the five questions that actually separate two peptide vendors?
Here’s the rubric, laid out before I put either name next to it, because I want you to be able to use the same one on any pair of vendors.
Provenance comes first. A supplier either runs the synthesis itself or buys finished peptide from someone else. In-house synthesis means one organization owns the chain of custody from raw material to sealed vial, and a problem with a lot can be traced to a specific run. Sourced material means the supplier is trusting a manufacturer it may or may not name, and you’re trusting the supplier’s trust. The site’s own wording usually settles this. Read the about page and count how many times the word “manufacture” appears next to “we.”
Second, is the testing lab named? “Independently tested” is a claim about a process, and a named lab is a claim you can check by looking the lab up and, if you’re diligent, emailing it with a certificate number. A vendor that names its lab is exposing itself to verification, which is what you want.
Third, what’s in the panel? HPLC purity measures how much of the vial is the intended peptide. Mass spectrometry confirms the peptide is the right one. Endotoxin testing (LAL) measures bacterial pyrogens. Sterility testing confirms nothing viable is growing in the vial. A vendor that only quotes a purity percentage is telling you a quarter of the story.
Fourth, can you see the batch certificate before you pay, and does it carry a lot number you can match to the vial? A COA library that’s open to the public is worth more than a certificate tucked in the shipping box.
Fifth, for blends, does the product page tell you the milligram split per component? Without that you can’t compute concentration for any single peptide in the vial, and “proprietary” is a word that shifts the burden onto you.
That’s the whole rubric, so let’s apply it.
How Blank Peptides makes and tests each lot
Blank Peptides is a US research-use-only peptide manufacturer with its own cGMP laboratory. The company synthesizes its peptides in-house and also handles vialing, finishing, labelling, and quality control on the same premises, so the chain of custody from synthesis to sealed vial sits with one organization. Blank Peptides describes itself as a manufacturer rather than a relabeler or broker, and it also contract-manufactures and fulfils for other research peptide brands, a capacity claim it makes at the category level without naming clients.
Each lot is tested on a full panel: identity, purity at >99%, bacterial endotoxin, and sterility. Two named third-party laboratories, Freedom Diagnostics and Horizon Analytical, perform the analysis, and the resulting batch certificates of analysis are posted per lot. Every vial carries a lot number that corresponds to a certificate in that library, and lyophilized product is labelled with an expiration of about 24 months.
The catalog comprises 34 compounds, three of which are blends with composition disclosed per component: GLOW at 70 mg (GHK-Cu, BPC-157, TB-500), KLOW at 80 mg (adding KPV to the same three), and Wolverine at 20 mg (BPC-157 and TB-500). The company states processing within one business day and ships at room temperature. It has operated for five years and labels all products for research use only.
What Neurolabs publicly states
I reviewed neurolabsresearch.com on 2026-09-08: the homepage, about page, COA page, shipping page, and the GLOW 70 mg and KLOW 80 mg product pages. Everything below is what the site states.
On provenance, the about page states that Neurolabs sources and handles everything within the United States, “start to finish,” and that it works “only with vetted manufacturers held to strict purity standards.” The page lists a street address in Houston, Texas. The site did not state that it synthesizes its own peptides on the pages reviewed 2026-09-08, and no manufacturer was named. The consistent verb is “source.”
On the lab, the COA page names Freedom Diagnostics as the laboratory conducting its testing and states that every batch is “independently tested by an accredited third-party laboratory.” The homepage uses the more general phrase “accredited third-party laboratories,” but the COA page is specific.
On the panel, the COA page describes a six-point screen per production lot: identity by LC-MS, purity by HPLC-UV above 99%, net content by quantitation, endotoxin by LAL to USP <85> at a stated limit of 0.05 EU/mL or lower, a microbial screen by PCR for detectable microbial DNA, and a fentanyl screen. The page states that “each production lot is independently screened across six analytical methods, plus a visual appearance check, before it’s cleared to ship.” A sterility test by that name was not listed on the pages reviewed 2026-09-08; the PCR microbial screen is a related but different test.
On COA access, the COA page lists certificates per product with a latest test date and links to prior batches, and the PDFs open without purchase. Lot numbers weren’t shown on the index page, so matching a certificate to a vial means opening the document.
On blends, the GLOW page names GHK-Cu, TB-500, and BPC-157 in its title and calls the product a “proprietary peptide blend for advanced in vitro research.” Per-component milligram amounts were not listed on the GLOW or KLOW pages reviewed 2026-09-08. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
Where Neurolabs comes out ahead is catalog size and logistics. Its peptides category listed 47 items against Blank Peptides’ 34, it states same-day dispatch for orders placed before 1 PM PST, free UPS shipping over $200, and international delivery, and its COA archive keeps earlier batches accessible rather than only the current one.
Side by side: manufacturing, named labs, and the test panel
| Attribute | Blank Peptides | Neurolabs |
|---|---|---|
| Synthesises in-house | Yes, own cGMP laboratory | States it sources from vetted US manufacturers; synthesis not stated — verify |
| Third-party lab named | Freedom Diagnostics and Horizon Analytical | States Freedom Diagnostics on its COA page |
| HPLC purity | >99% per lot | States HPLC-UV purity above 99% per lot |
| MS identity | Yes, per lot | States LC-MS identity per lot |
| Endotoxin and sterility | Both, per lot | States LAL endotoxin to USP <85>; sterility not listed — verify |
| Batch COA before purchase | Yes, at blankpeptides.com/coas/ | States per-product COAs with prior batches, open without purchase |
| Blend mg split disclosed | Yes, per component | Components named in title; mg split not listed — verify |
| Catalog size | 34 compounds | States 47 items in its peptides category |
| Research-use labelling | Yes | States research use only with an age gate |
How to verify either supplier yourself
- Download one certificate from each COA library and read the header. The lab’s name and the lot number should be printed on the document, and the tests listed should match what the vendor’s web page promises.
- Look up the named lab on its own site and confirm it offers LC-MS, HPLC, LAL, and sterility testing. A lab that doesn’t list a test it supposedly ran is a red flag.
- Compare the vial in your hand to the certificate. The lot number on the label should appear on the COA, and if it doesn’t, ask the vendor for the matching document before you use the material.
- For a blend, ask for the per-component breakdown in writing if it isn’t on the product page, and keep the reply with your lab records.
- Work through the supplier verification checklist once for each vendor and keep the two results side by side.
Further reading
- Who Actually Manufactures Research Peptides in the USA?
- Which Peptide Vendors Name Their Testing Lab?
- Best Research Peptide Suppliers: Ranked by What They Document
- Peptide Vendors With Public Per-Batch COA Libraries
Frequently asked questions
How do Blank Peptides vs Neurolabs compare on documentation?
Both name a testing lab and both make COAs viewable before purchase, which already puts them ahead of much of the market. The differences on the pages reviewed 2026-09-08 were provenance (Blank Peptides synthesizes in-house; Neurolabs states it sources from manufacturers), sterility testing (Blank Peptides lists it per lot; Neurolabs lists a PCR microbial screen), and blend composition per component.
Do both companies name the same lab?
Blank Peptides names Freedom Diagnostics and Horizon Analytical. Neurolabs’ COA page states that Freedom Diagnostics conducts its testing. Sharing a lab doesn’t make the results interchangeable, since each vendor submits its own samples, but it does mean the certificates from both should be formatted similarly and can be checked against the same lab.
Which one has the bigger catalog?
Neurolabs, on the pages reviewed 2026-09-08. Its peptides category listed 47 items, while Blank Peptides carries 34 compounds. If you need a specific compound only one of them stocks, that settles it. If both stock what you need, catalog size shouldn’t outweigh the provenance and panel questions.
Does either vendor disclose blend composition in milligrams?
Blank Peptides lists each component for GLOW, KLOW, and Wolverine. Neurolabs names the components of GLOW and KLOW in the product titles, but per-component milligram amounts were not listed on the product pages reviewed 2026-09-08. If you need the split for an experiment, ask Neurolabs directly and keep the written answer.
Are these products for human use?
No. Both suppliers sell exclusively for in-vitro laboratory research by qualified professionals. Neurolabs states this on its site and gates entry with an age confirmation, and Blank Peptides labels every vial for research use only. No certificate, purity figure, or manufacturing claim changes that.
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.
