49 suppliers graded7 FDA warning letters8 closures on recordUpdated October 2026 · How grades are earned
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October 2026 · 49 suppliers graded

Every peptide supplier says it is tested. We checked which ones can prove it.

Each supplier is run through the same eight verification checks and graded A+ to F on what its documents and the public record actually support. No reviews, no stars, no pay-to-play.

See all gradesLook up a supplier

Grades are editorial fact-check results computed from public facts. Every supplier listed sells materials labeled for laboratory research use only.

Latest grades Grade · evidence /100
1Paramount Peptides8/8 checks · Lot-level open certificates · USA83/1002Core Peptides8/8 checks · Lot-level open certificates · USB+82/1003Sports Technology Labs7/8 checks · Open certificates · USB+79/1004Koi Peptides8/8 checks · Lot-level open certificates · USB+78/1005Ascension Peptides8/8 checks · Lot-level open certificates · USB+77/100
49suppliers graded this month
10pass all eight checks
31publish open certificates
6operating with an FDA letter

Highest grades, October 2026

All 49 graded, sortable →

#SupplierGradeChecksTestingPublic COAsLot-levelBased
Best overall · October 2026
1Paramount Peptidesparamountpeptides.comA83/1008/8YesYesYesUSReportVisit site
2Core Peptidescorepeptides.comB+82/1008/8YesYesYesUSReportVisit site
3Sports Technology Labssportstechnologylabs.comB+79/1007/8YesYesNot verifiedUSReportVisit site
4Koi Peptideskoipeptides.comB+78/1008/8YesYesYesUSReportVisit site
5Ascension Peptidesascensionpeptides.comB+77/1008/8YesYesYesUSReportVisit site
6Licensed Peptideslicensedpeptides.comB+77/1008/8YesYesYesUSReportVisit site
7Alpha Peptidesalpha-peptides.comB+76/1008/8YesYesYesUSReportVisit site
8Simple Peptidesimplepeptide.comB+76/1007/8YesNot verifiedYesUSReportVisit site
Best for prefilled pens
9Peptide Perfectionpeptideperfection.comB75/1008/8YesYesYesUSReportVisit site
10Pure Peptide Labspurepeptidelabs.shopB73/1008/8YesYesYesUSReportVisit site

Checks = how many of the eight verification items passed. Testing, public and lot-level certificates are read from the supplier's own pages; "not verified" earns nothing. How the grade is earned.

The eight checks

Pass marks come only from documents anyone can open

1

An independent laboratory, named

"Third-party tested" is a claim. A laboratory with a name you can look up is evidence. We record both separately.

2

Certificates anyone can open

If the certificate is behind a login or arrives only after purchase, it cannot be verified and it does not count.

3

Certificates tied to a lot

One undated "sample" report reused across a catalog says nothing about the lot that ships. Lot numbers do.

4

A company that can be found

A street address or a phone number. Email alone is a partial pass; a web form alone is a fail.

5

Research-use-only labeling

Every supplier here sells materials labeled for laboratory research. We check that the labeling is present.

6

No regulator's letter on file

A public FDA warning letter fails this check and caps the grade at C. 6 operating suppliers are on the watchlist for this reason.

7

Testing stated at all

A supplier that makes no testing claim cannot pass the checks that depend on one.

8

Storefront operating

8 closed and 5 unverifiable suppliers are kept on record without a grade.

What a grade means

A letter is a checklist result, not an opinion

Six lines of evidence are weighted toward the ones a storefront cannot fake for free: testing and certificates 40%, transparency 30%, track record 20%, with catalog, pricing and service sharing the last 10%. The weighted total is the evidence score; the letter is read off a fixed scale. A public FDA warning letter caps the score at 59 no matter what else verifies.

Read the full method · See the watchlist

  • A+90–100Every material claim is backed by an openable document.
  • A83–89Claims hold up; minor gaps in the record.
  • B+ / B68–82Core testing claim verified; a notable gap elsewhere.
  • C+ / C50–67Mixed record, or an FDA letter caps the grade here.
  • D / Fbelow 50Few or no claims could be verified.

Shortlists by a single verifiable fact

All best-of lists →

3 qualify

Prefilled peptide pens

Peptide Perfection
highest gradeB41 qualify

US-based suppliers

Paramount Peptides
highest gradeA31 qualify

Suppliers with public certificates of analysis

Paramount Peptides
highest gradeA21 qualify

Lot-level third-party testing

Paramount Peptides
highest gradeA8 qualify

Budget-priced suppliers

Alpha Labs Peptides
highest gradeB14 qualify

Suppliers that ship internationally

Koi Peptides
highest gradeB+

Recently checked

Full grade sheet →

Is BioLongevity Labs legit?8/8 checks · Lot-level open certificates · USBIs Limitless Biotech legit?7/8 checks · Lot-level open certificates · USBIs Evolve Peptides legit?8/8 checks · Lot-level open certificates · USBIs Alpha Labs Peptides legit?7/8 checks · Open certificates · USBIs Biotech Peptides legit?7/8 checks · Lot-level open certificates · USBIs Verified Peptides legit?7/8 checks · Lot-level open certificates · USB

On the watchlist

Every letter, linked to fda.gov →

6 suppliers still trading under a public FDA warning letter. A letter fails the regulatory check and caps the grade at C.

Is NuScience Peptides legit?FDA letter 2026-08-24 · 5/8 checksCIs Prime Peptides legit?FDA letter 2024-12-10 · 7/8 checksCIs PureRawz legit?FDA letter 2025-09-08 · 3/8 checksFIs Swiss Chems legit?FDA letter 2024-12-10 · 7/8 checksCIs Umbrella Labs legit?FDA letter 2021-05-18 · 6/8 checksCIs Xcel Peptides legit?FDA letter 2024-12-10 · 4/8 checksD

Do the checking yourself

All guides →

What an FDA Warning Letter Actually Says: Anatomy, Terms and How to Read One

Anatomy of an FDA warning letter to a peptide supplier: unapproved new drug, misbranded, the 15-day response window, heavy evidence but not a court finding.

Trustpilot Profile Removed: What the Notice Means for a Peptide Supplier

What Trustpilot's removal notice means for a peptide supplier, why 21 of 62 suppliers in our data set show it, and why we score it as a stated absence.

Research Use Only Labeling Explained: What the RUO Disclaimer and Buyer Gate Are For

What research-use-only labeling is, what a supplier's RUO disclaimer and purchaser gate do, how we check them, and why health claims beside RUO are flagged.

Peptide Testing Labs Explained: What a Lab Name on a Certificate Tells You

Neutral explainer of the labs named on peptide supplier COAs (Janoshik, Vanguard, MZ Biolabs, Freedom Diagnostics, Ethos, Kovera): what a name proves.

Questions readers ask

How does a peptide supplier earn its grade here?

We run the same eight verification checks on every supplier, then weight six lines of evidence: independent testing and certificates (40%), transparency about the company (30%), track record (20%), catalog breadth (3%), pricing (3%) and ordering service (4%). The weighted total is an evidence score out of 100, converted to a letter from A+ down to F. A public FDA warning letter caps the score at 59, grade C. A supplier whose site cannot be reached or verified is listed but not graded.

Is this a review site?

No. There are no customer reviews, star ratings or testimonials anywhere on Peptide Truth, and we add no review markup to our pages. A grade is an editorial fact-check result produced by a published formula.

What is the single most telling check?

Whether you can open a certificate of analysis for a specific lot, signed by a laboratory that is named, without logging in or buying. A supplier that can show that document has little reason to hide anything else.

How current are the grades?

Facts are re-checked on a rolling schedule and every page regenerates when the data changes. The month printed on each page is the last regeneration.

Who pays for this site?

Some outbound links may carry referral codes that earn a commission if you order. The formula does not know which links those are, and the funding page spells out every relationship we have with the industry.