Independent side-by-side comparison of Certified Peptides and Zhuoyan Peptides — third-party lab grades, tested purity, COA availability, FDA warnings, and community ratings.
Bottom line: Zhuoyan Peptides shows higher average tested purity (99.7% vs 99.3%).
Every figure below is either measured by an independent laboratory or read from the vendor's own website, and the source is named against it. PeptideAtlas is not affiliated with either vendor.
Certified Peptides: 4 independent Janoshik assays, across 4 substances, median measured purity 99.7%, most recent 2026-04-01. Zhuoyan Peptides: 4 independent Janoshik assays, across 4 substances, median measured purity 99.7%, most recent 2026-03-24.
| Attribute | Certified Peptides | Zhuoyan Peptides |
|---|---|---|
| Third-party tests | 4 tests, avg purity 99.3% | 4 tests, avg purity 99.7% |
| COA available | No | No |
| Endotoxin tested | No | No |
| FDA warnings | None on record | None on record |
| Substance | Certified Peptides | Zhuoyan Peptides |
|---|---|---|
| Retatrutide 5mg | 99.70% (1 assay, latest 2026-04-01) | Not tested |
| Selank 10mg | 99.79% (1 assay, latest 2026-03-31) | Not tested |
| Epitalon 50mg | 98.00% (1 assay, latest 2026-03-31) | Not tested |
| Lpamorelin 10mg | 99.77% (1 assay, latest 2026-03-31) | Not tested |
| Bb10(bpc 5mg + TB 5mg) | Not tested | purity not reported (1 assay, latest 2026-03-24) |
| Ss-31 10mg | Not tested | 99.69% (1 assay, latest 2025-06-16) |
| Epitalon 10mg | Not tested | 99.54% (1 assay, latest 2025-06-16) |
| Tirzepatide 10mg | Not tested | 99.80% (1 assay, latest 2025-03-06) |
| Checked | Certified Peptides | Zhuoyan Peptides |
|---|---|---|
| Certificates of analysis | Not stated | None found on the site |
| Products listed | Not stated | 20 |
| Ships to | Not stated | Worldwide |
| Stated origin | Not stated | China |
Neither — both have 4 on file. Certified Peptides: 4 independent Janoshik assays, across 4 substances, median measured purity 99.7%, most recent 2026-04-01. Zhuoyan Peptides: 4 independent Janoshik assays, across 4 substances, median measured purity 99.7%, most recent 2026-03-24.
We have not read Certified Peptides' site, and we found no certificates of analysis anywhere on Zhuoyan Peptides' site. A published COA is the vendor's own document; the assay figures elsewhere on this page are independent of it.
Certified Peptides does not state a shipping region, and Zhuoyan Peptides states it ships to Worldwide. Both are read from the vendors' own sites.
Full profiles: Certified Peptides, Zhuoyan Peptides.
Full lab-test records: All 4 Certified Peptides lab tests, All 4 Zhuoyan Peptides lab tests.
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