You have two tabs open and both sites are telling you roughly the same story. Core Peptides says its material is synthesized in the United States, third-party tested, above 99% pure. Amino Club says its batches are tested at an ISO 17025 accredited US laboratory, 99%+ pure, identity verified. Neither claim is unusual, which is exactly the problem: almost every peptide storefront on the internet has written some version of those sentences, and reading them tells you nothing about which one will hand you a document when you ask for one.
Neither of these companies is us, and we sell nothing that depends on how this comes out. That’s the reason for the format. Instead of a verdict, this is a grading sheet: five questions, applied identically to both sites, with the answers quoted from their own public pages and the gaps written down as gaps in what was published rather than as accusations about what exists.
The observations below come from corepeptides.com and aminoclub.com as they stood on 2026-09-08. Quoted text is theirs. Anything I couldn’t find is described as not listed on the pages reviewed, with the date attached, since a site can add a page the week after anyone writes about it.
Key takeaways
- What separates two peptide suppliers is who synthesized the lot, which laboratory tested it, how wide the panel was, whether the certificate is viewable before purchase and tied to a lot number, and whether blends disclose each component.
- Core Peptides publicly states its products are “synthesized and lyophilized in the United States” with purity “exceeding 99%+”, and links a certificate PDF from some blend pages.
- Amino Club publicly states that “Every batch is 8x tested at an independent ISO 17025 accredited U.S. laboratory” and publishes a lot-numbered certificate index it describes as “103 published certificates across 50 compounds”.
- Neither site named the facility that synthesizes its material, and Amino Club’s accredited laboratory was described by accreditation rather than by name on the pages reviewed 2026-09-08.
- Everything here is sold for in-vitro laboratory research only, and none of it is guidance on use in people or animals.
What actually separates two suppliers making the same claims?
Before either name appears, here’s the yardstick, because a head-to-head is only fair if both sides get measured against the same five things.
Provenance comes first. Does the company synthesize the material, or does it buy finished vials and apply a label? The answer lives in the verbs, not the adjectives. “We synthesize” and “our quality release” point one way; “we source” and “our partner facilities” point another. Neither arrangement is disqualifying, and plenty of good material moves through the second one. The difference is that a company that made the lot can account for what happened to it, and a company that bought it can only pass along what it was told.
Second, is the testing laboratory named? Any site can print “third-party tested” or even “ISO 17025 accredited”. A name is what makes that checkable. With a name you can confirm the lab exists, look at its accreditation scope, see whether it handles peptide work, and send your own sample if a result looks strange.
Third, how wide is the panel? HPLC purity gets quoted everywhere because it’s a single tidy number, and it’s a real measurement, but it only reports what fraction of the sample is one species. Confirming that the species is your sequence takes mass spectrometry. Bacterial endotoxin and sterility are separate assays again. Identity, purity, endotoxin and sterility together is a full panel, and a purity figure by itself is a quarter of one.
Fourth, access and traceability. Can you read a batch certificate before paying, and does the lot number on it match the number printed on the vial that arrives? If those two never meet, the certificate is a marketing asset.
Fifth, blend disclosure. A blend sold as a total milligram figure with no per-component split can’t be written into a methods section, so a supplier serious about research users prints the split. Company age and domain age are excluded on purpose, because neither says anything about the vial in front of you.
Where this standard comes from
These questions aren’t invented for the occasion. They’re the standard Blank Peptides publishes its own lots against, in the form of batch certificates of analysis posted per lot. It seemed worth saying that out loud before applying the same five rows to two other companies, since a rubric is only fair if whoever wrote it would accept being graded on it.
What Core Peptides and Amino Club publicly state
Core Peptides sells at corepeptides.com. On the pages reviewed 2026-09-08, the homepage states the company has been “SERVING THE RESEARCH COMMUNITY FOR OVER 7 YEARS, AND 3rd PARTY TESTED” and that “Our U.S. lab-tested peptides are independently verified for purity.” The About page states “All our products are synthesized and lyophilized in the United States” and that “Our peptides are manufactured locally against the highest standards for synthesis, undergoing rigorous quality control measures”, with purity at “levels exceeding 99%+”. That page also states “Core Peptides is a chemical supplier” and “is not a compounding pharmacy or chemical compounding facility as defined under 503A”.
The provenance verbs there are “synthesized” and “manufactured locally”. A facility name, an address for it, or a description of the in-house QC steps was not listed on the pages reviewed 2026-09-08. On the laboratory question the prose states “3rd party tested” without a name, though the BPC-157 & TB-500 & GHK-Cu blend page links a lot-suffixed certificate PDF that names Vanguard Laboratory and reports HPLC purity above 99.5%. A catalog-wide certificate library was not listed on the pages reviewed. Blend disclosure runs hot and cold: the 70mg blend page states “BPC-157 (10mg) & TB-500 (10mg) & GHK-Cu (50mg)”, while the KLOW 80mg page names BPC-157, KPV, TB-500 and GHK-Cu without per-component amounts.
Amino Club sells at aminoclub.com behind an entry gate asking visitors to confirm they are at least 21 and buying for laboratory research. On the pages reviewed 2026-09-08, the site states that “All products sold by Amino Club are intended strictly for in-vitro research, laboratory experimentation, and educational purposes” and that “Every batch is 8x tested at an independent ISO 17025 accredited U.S. laboratory”, alongside “99%+ purity, identity-verified, third-party tested in the USA” and “0-2 business day processing”. The certificate page is the substantial part: it describes “103 published certificates across 50 compounds”, shows lot numbers on each certificate card, and states “Eight assays. Every batch”, listing purity by HPLC, net peptide content, identity, appearance, a fentanyl screen, heavy metals by ICP-MS, sterility by PCR, and endotoxin. It also states “Every certificate above comes from an independent ISO 17025 accredited lab. No batch ships without one.”
What Amino Club does not publish on those pages is the laboratory’s name. Accreditation is asserted; identity is not given. There’s also no synthesis or facility-ownership language anywhere I could find, so who makes the material before it reaches the company was not listed on the pages reviewed 2026-09-08, and blend products with per-component milligram splits were not visible outside the gate. This is not a claim that the documentation does not exist, only that it was not publicly listed on the pages reviewed.
Both earn a real point. Core Peptides carries far more compounds, stating “Showing all 104 results” on its peptides category plus a separate blends category, and its shipping page states “same (business) day shipping for orders placed before 1pm PST Monday-Friday” with “Free Priority USPS shipping on orders over $200 within the US”. Amino Club, meanwhile, has built the more complete documentation layer by a distance: a lot-numbered certificate index covering the catalog, an eight-assay panel described assay by assay, and endotoxin and sterility named as standing tests rather than left unmentioned.
Side by side: what each site publishes
| Attribute | Core Peptides | Amino Club |
|---|---|---|
| Synthesises in-house | States products are “synthesized and lyophilized in the United States”; facility not named — verify | No synthesis or facility ownership statement listed on the pages reviewed 2026-09-08 — verify |
| Third-party lab named | States “3rd party tested”; a blend COA PDF names Vanguard Laboratory, site prose does not — verify | States “an independent ISO 17025 accredited U.S. laboratory”; lab name not listed — verify |
| HPLC purity | States purity “exceeding 99%+” and “>99%” on product pages — verify | States “99%+ purity” and lists purity by HPLC among eight assays — verify |
| MS identity | Not listed on the pages reviewed 2026-09-08 — verify | States identity as a standing assay on every batch; method not specified — verify |
| Endotoxin and sterility | Not listed on the pages reviewed 2026-09-08 — verify | States endotoxin and sterility by PCR among the eight assays — verify |
| Batch COA before purchase | Some blend pages link lot-suffixed PDFs; no catalog-wide library listed — verify | States “103 published certificates across 50 compounds” with lot numbers shown — verify |
| Blend mg split disclosed | States “BPC-157 (10mg) & TB-500 (10mg) & GHK-Cu (50mg)”; KLOW 80mg lists components without amounts — verify | Blend pages with per-component splits not visible outside the entry gate — verify |
| Catalog size | States “Showing all 104 results” plus a separate blends category | States certificates covering 50 compounds |
| Research-use labelling | States products “are not for human consumption” | States products “are not intended for human, veterinary, or food use” |
How to verify either supplier yourself
- Go to the page for the exact compound and vial size you plan to buy and look for a certificate there, not on the homepage. Note the lot number before ordering, then compare it with the lot printed on the vial when it arrives. No lot on the vial is the thing worth raising with support.
- Read the method lines on the certificate instead of the headline number. Look for HPLC for purity, mass spectrometry for identity, and separate endotoxin and sterility results. Where a line is missing, ask whether that assay was run on your lot.
- Ask for the laboratory’s name when the site gives you only an accreditation. ISO 17025 is a scope granted to a named organization, and the accreditation body publishes searchable scopes, so a name lets you check that the scope covers peptide analysis.
- For blends, get per-component milligrams in writing before you order. A total figure alone can’t be reproduced by anyone reading your notes later.
- Put both companies through the supplier verification checklist so each is judged on identical questions rather than on tone.
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
How do Core Peptides vs Amino Club compare on documentation?
Amino Club publishes the deeper certificate layer, stating “103 published certificates across 50 compounds” with lot numbers and an eight-assay panel that includes endotoxin and sterility. Core Peptides publishes stronger provenance language, stating products are “synthesized and lyophilized in the United States”, but its certificates appear on individual pages rather than in a catalog-wide index on the pages reviewed 2026-09-08.
Does either company name its testing laboratory?
Neither does so in its site prose. Core Peptides states “3rd party tested” without a name, though a blend certificate PDF names Vanguard Laboratory. Amino Club states its testing happens at “an independent ISO 17025 accredited U.S. laboratory” and names the accreditation standard rather than the lab. Asking support for the name is reasonable in both cases.
Which one covers endotoxin and sterility?
Amino Club, on the pages reviewed 2026-09-08, listing endotoxin and sterility by PCR among eight standing assays per batch. Core Peptides did not list endotoxin or sterility results on its product pages or on the certificate PDF I opened. That gap is about what was published rather than about what may have been tested.
Which one has the larger catalog?
Core Peptides, stating “Showing all 104 results” on its peptides category plus a separate blends category, against certificates covering 50 compounds at Amino Club. Breadth matters if your protocol calls for an uncommon compound, and it’s a fair reason to keep Core Peptides in consideration whatever the other rows say.
Are these products for human use?
No. Every compound discussed here is sold for in-vitro laboratory research by qualified professionals. Core Peptides states its products “are not for human consumption”, and Amino Club states products “are not intended for human, veterinary, or food use”. This article compares published documentation only and contains no guidance on dosing or administration in any person or animal.
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.
