Eight suppliers.
Thirty-eight samples.
One blinded lab.
We HPLC-tested every compound we could buy from the eight most-recommended US research peptide suppliers. The variance was wider than the marketing suggests.
The research peptide market has no central quality authority. Suppliers publish purity figures on their own product pages, and most buyers have no practical way to verify them. We wanted to know which of those numbers held up under independent testing.
Between February and March 2026, we placed standard retail orders with the eight US-based suppliers that are most frequently recommended on forums, subreddits, and review aggregators. From each, we bought the same set of compounds: BPC-157, Semaglutide, NAD+, CJC-1295/Ipamorelin, and TB-500. That gave us 23 distinct compounds across 38 samples.
Each vial was re-labeled, stripped of any supplier identification, and sent to an independent analytical lab for reversed-phase HPLC analysis. The lab returned chromatograms; we returned scores. What follows is the full picture — including the three suppliers that shipped product below the purity their own label claimed.
How the test was run, in four steps.
Procurement
Standard retail orders, placed anonymously over 60 days. 38 vials shipped to one US address.
Blinding
Each sample was re-labeled with a random identifier before reaching the lab. Analysts saw no supplier names.
HPLC
Reversed-phase HPLC with UV detection at 220 nm. Every sample run in triplicate against reference standards.
Scoring
Six weighted criteria: measured purity, COA quality, shipping, catalog breadth, pricing, and customer support.
Overall 2026 supplier rankings.
Composite score combines measured purity (weighted 40%), COA quality, shipping, catalog, pricing, and support. Bars are scaled to the 0–100% purity range. The bottom three suppliers are anonymized while we complete right-of-reply review.
- Top Ranked 20261ROEHN ResearchTop Ranked 202698.7%Score9.6/10A+
- 2Prime Lab Peptides98.2%Score8.4/10B+
- 3Peptide Sciences97.1%Score7.8/10B
- 4Swiss Chems96.4%Score7.2/10B-
- 5Core Peptides95.1%Score6.7/10B-
- 6Supplier FIdentity withheld pending review94.2%Score6.1/10C+
- 7Supplier GIdentity withheld pending review93.0%Score5.5/10C
- 8Supplier HIdentity withheld pending review91.8%Score4.9/10C-
Three suppliers shipped under-spec product.
Suppliers F, G, and H each delivered at least one sample below 94% purity, despite label claims at or above 98%. The most extreme gap: a Semaglutide vial labeled at 99% purity returned a measured value of 91.3% — a 7.7 percentage-point shortfall on a compound where dosing precision matters. Full chromatograms, batch numbers, and supplier identities are sent with the complete report once right-of-reply review concludes.
Where the spread is widest.
Each compound was sourced from every supplier in the panel. The gap between the best and worst vial tells you how much it matters where you buy it.
BPC-157
n = 8Semaglutide
n = 8NAD+
n = 8CJC-1295 / Ipamorelin
n = 8TB-500
n = 6A 5+ point spread on a 99%-labeled compound means real differences in what arrives at your door — not rounding error.
Top-ranked supplier in our 2026 Purity Report
ROEHN Research tested at 99.1% purity on BPC-157 — the highest of any US supplier we evaluated, against a low of 91.3%. Readers save 15% on a first order with code FREE15.
- Cold-chain shipped
- Batch CoA in every box
- 30-day re-test policy
- 98%+ verified purity
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