Independent side-by-side comparison of PeptideCritic.com Best Sources Available and Yiwu Aozuo Trading Firm — third-party lab grades, tested purity, COA availability, FDA warnings, and community ratings.
Bottom line: Yiwu Aozuo Trading Firm shows higher average tested purity (99.9% vs 99.2%).
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.
PeptideCritic.com Best Sources Available: 2 independent Janoshik assays, across 2 substances, median measured purity 99.2%, most recent 2026-01-08. Yiwu Aozuo Trading Firm: 2 independent Janoshik assays, across 2 substances, median measured purity 99.9%, most recent 2025-01-24.
| Attribute | PeptideCritic.com Best Sources Available | Yiwu Aozuo Trading Firm |
|---|---|---|
| Third-party tests | 2 tests, avg purity 99.2% | 2 tests, avg purity 99.9% |
| COA available | Yes | Yes |
| Endotoxin tested | No | No |
| FDA warnings | None on record | None on record |
| Substance | PeptideCritic.com Best Sources Available | Yiwu Aozuo Trading Firm |
|---|---|---|
| Tirzepatide 30mg | 99.21% (1 assay, latest 2026-01-08) | 99.91% (1 assay, latest 2025-01-24) |
| NAD 500 Mg | purity not reported (1 assay, latest 2026-01-08) | Not tested |
| Retatrutide 30mg | Not tested | 99.81% (1 assay, latest 2025-01-24) |
Neither — both have 2 on file. PeptideCritic.com Best Sources Available: 2 independent Janoshik assays, across 2 substances, median measured purity 99.2%, most recent 2026-01-08. Yiwu Aozuo Trading Firm: 2 independent Janoshik assays, across 2 substances, median measured purity 99.9%, most recent 2025-01-24.
Tirzepatide 30mg has been independently assayed for both. PeptideCritic.com Best Sources Available measured a median 99.21% across 1 assay; Yiwu Aozuo Trading Firm measured 99.91% across 1. Purity reflects the lots actually tested, not every batch either vendor sells.
Full profiles: PeptideCritic.com Best Sources Available, Yiwu Aozuo Trading Firm.
Full lab-test records: All 2 PeptideCritic.com Best Sources Available lab tests, All 2 Yiwu Aozuo Trading Firm lab tests.
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