UK research peptide suppliers, compared
Suppliers compared on criteria you can check yourself rather than on marketing language. Every attribute below is recorded from the supplier’s own public website, with the date it was checked.
| Supplier | Stated purity | COA access | Testing | Format | Checked |
|---|---|---|---|---|---|
| Bluewell Peptides | ≥99.1% by HPLC | Public library | Batch HPLC by manufacturing partner, re-verified by third-party lab Axonis Analytics | Lyophilised powder | 29 Jul 2026 |
| Express Peptides | Minimum purity of >99% (stated in FAQ) | Not stated | Not stated | Both | 29 Jul 2026 |
| Imperial Peptides | >99.1% (COA page); ≥99% (product spec tables) | Public library | HPLC and/or MS; ICP-based methods for heavy metals; bacterial endotoxin test (BET) | Lyophilised powder | 29 Jul 2026 |
| MY PEPTIDES | 99%+ HPLC | Public library | HPLC purity + mass spectrometry identity | Pre-mixed solution | 29 Jul 2026 |
| Peptides Lab UK | 99% purity guarantee; >99% (HPLC verified); typical HPLC purity 99.0–99.7% | With order only | HPLC purity, mass-spectrometry identity and bacterial endotoxin testing, stated as carried out by Optima Labs, an independent UK analytical facility | Lyophilised powder | 29 Jul 2026 |
| Peptides UK | Stated variously as minimum 99%, >98% and ≥98%/≥99% | With order only | HPLC and MS-UPLC analysis | Lyophilised powder | 29 Jul 2026 |
| Regen Peptides | 99%+ purity verified, tested by independent laboratories | Public library | HPLC and mass spectrometry (no laboratory named in site copy) | Lyophilised powder | 29 Jul 2026 |
| Tide Labs | 99%+ purity; >99% purity | With order only | Independent UKAS-verified laboratory partner; HPLC and mass spectrometry | Lyophilised powder | 29 Jul 2026 |
| UK Peptide Lab | Minimum specification 98% by HPLC; most active compounds test above 99% | Public library | HPLC-UV/MS, potency assay and endotoxin testing (LAL, USP 85), via Janoshik Analytical, Krause Analytical and Chromate Analytics | Lyophilised powder | 29 Jul 2026 |
| UK Peptides | >99% headline; per-lot certificates range from ≥95.0% to ≥99.9% | Public library | Purity by HPLC (area %); identity confirmed by mass spectrometry. Certificates described as in-house | Lyophilised powder | 29 Jul 2026 |
| XL Peptides | 99% or higher, made in a cGMP-compliant ISO9001 facility | Public library | Batch reports from Janoshik S.R.O Laboratories, Prague | Lyophilised powder | 29 Jul 2026 |
Attributes are recorded from each supplier’s own public website on the date shown, and go out of date. “Not stated” means we did not find the information on their site, not that it is absent from their business. Rows are alphabetical and the order is not a ranking. Company names and marks are the property of their respective owners. Verify anything that matters directly with the supplier before purchasing.
COA access is the one that separates suppliers most sharply. Almost every vendor states that a Certificate of Analysis ships with an order. Far fewer publish a library you can browse before buying — which is the only version that lets you check the testing format and purity figures while you are still deciding. Of the 11 suppliers listed here, 7 do so.
Stated purity is quoted verbatim. Note that a purity figure only means something when it is tied to a batch number you can match against the vial in front of you; a site-wide “99%+” claim with no per-batch document behind it is a marketing statement.
Format records whether products ship as lyophilised (freeze-dried) powder needing reconstitution, or as a pre-mixed solution ready to use. 2 of 11 listed suppliers ship pre-mixed at least some of their range. Neither format is simply better — they trade off differently on stability, shipping and handling error. See pre-mixed vs lyophilised peptides.
Testing records the analytical method as the supplier describes it. HPLC quantifies purity; mass spectrometry confirms identity. The two answer different questions, and a supplier doing only the first has not confirmed the compound is what the label says.