Independent side-by-side comparison of HK Peptides and Zztai Peptide — third-party lab grades, tested purity, COA availability, FDA warnings, and community ratings.
Bottom line: Zztai Peptide shows higher average tested purity (99.3% vs 98.7%); Zztai Peptide has more published third-party tests (18 vs 5).
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.
HK Peptides: 5 independent Janoshik assays, across 5 substances, median measured purity 99.7%, most recent 2025-11-03. Zztai Peptide: 18 independent Janoshik assays, across 17 substances, median measured purity 99.5%, most recent 2025-12-19.
| Attribute | HK Peptides | Zztai Peptide |
|---|---|---|
| Independent lab grade | C | C |
| Third-party tests | 5 tests, avg purity 98.7% | 18 tests, avg purity 99.3% |
| COA available | No | No |
| Endotoxin tested | No | No |
| FDA warnings | None on record | None on record |
| Substance | HK Peptides | Zztai Peptide |
|---|---|---|
| Tirzepatide 30mg | 99.70% (1 assay, latest 2024-09-30) | 99.97% (1 assay, latest 2025-07-03) |
| Nad+ 500mg | purity not reported (1 assay, latest 2024-09-26) | purity not reported (1 assay, latest 2025-07-02) |
| Retatrutide 20mg | Not tested | 99.55% (2 assays, latest 2025-12-18) |
| HGH 24 IU | 95.42% (1 assay, latest 2025-11-03) | Not tested |
| KPV 10mg | 99.79% (1 assay, latest 2025-04-09) | Not tested |
| Tirzepatide 10mg | 99.70% (1 assay, latest 2024-09-30) | Not tested |
| DSIP 5mg | Not tested | 99.01% (1 assay, latest 2025-12-19) |
| Tirzepatide 60mg | Not tested | 99.95% (1 assay, latest 2025-12-18) |
| HGH 191AA (somatropin) 151U | Not tested | 97.83% (1 assay, latest 2025-12-18) |
| Mots-c 10mg | Not tested | 99.10% (1 assay, latest 2025-10-21) |
| Retatrutide 30mg | Not tested | 99.62% (1 assay, latest 2025-10-21) |
| Retatrutide 5mg | Not tested | 99.24% (1 assay, latest 2025-10-21) |
| Checked | HK Peptides | Zztai Peptide |
|---|---|---|
| Certificates of analysis | None found on the site | None found on the site |
| Products listed | 15 | 62 |
| Public pricing | Not stated | Listed on the site |
| Payment methods | Not stated | Credit Card, PayPal |
| Ships to | United States, Europe, Worldwide | United States, United Kingdom, Canada, Australia, New Zealand |
| Carriers | Not stated | DHL, FedEx, UPS, USPS |
| Stated origin | China | Hong Kong |
Zztai Peptide. HK Peptides: 5 independent Janoshik assays, across 5 substances, median measured purity 99.7%, most recent 2025-11-03. Zztai Peptide: 18 independent Janoshik assays, across 17 substances, median measured purity 99.5%, most recent 2025-12-19. These are third-party Janoshik assays published against the vendor, not the vendor's own certificates.
Tirzepatide 30mg has been independently assayed for both. HK Peptides measured a median 99.70% across 1 assay; Zztai Peptide measured 99.97% across 1. Purity reflects the lots actually tested, not every batch either vendor sells.
We found no certificates of analysis anywhere on HK Peptides' site, and we found no certificates of analysis anywhere on Zztai Peptide's site. A published COA is the vendor's own document; the assay figures elsewhere on this page are independent of it.
HK Peptides states it ships to United States, Europe, Worldwide, and Zztai Peptide states it ships to United States, United Kingdom, Canada, Australia, New Zealand. Both are read from the vendors' own sites.
Full profiles: HK Peptides, Zztai Peptide.
Full lab-test records: All 5 HK Peptides lab tests, All 18 Zztai Peptide lab tests.
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