Lab results
Peptide purity test results
Peptide purity results for 24 research peptides, from 12,325 independent lab tests of vials bought from shops. Each row shows how often samples passed, their median purity, and how often the vial held less than the label said. Peptide Vendor Reviews publishes every result with its certificate; look up any peptide below.
- A sample passes at 99.5% purity or more, a fill within 35% of the label, and a confirmed identity.
- Pass rates differ by compound: GHK-Cu samples passed 85% of the time, NAD+ 24%.
- GHK-Cu vials were the most often underfilled: 42% held more than 5% less than the label.
Peptide purity by compound
| Peptide | Tests | Passed | Median purity | Underfilled | Most common failure | Quality leader |
|---|---|---|---|---|---|---|
| Retatrutide401 shops tested | 4,543 | 78% | 99.89% | 25% | purity under 99.5%301 failed identity | Peptide Partners · A, 32 tests |
| Tirzepatide271 shops tested | 2,807 | 78% | 99.85% | 21% | purity under 99.5%133 failed identity | Guangzhou Jeep Biotechnology JEEP · A, 16 tests |
| GHK-Cu148 shops tested | 980 | 85% | 99.9% | 42% | amount in the vial more than 35% off the label11 failed identity | Reta-Peptide · A, 28 tests |
| BPC-157147 shops tested | 922 | 50% | 99.6% | 26% | purity under 99.5%56 failed identity | HK Peptides · B, 22 tests |
| Tesamorelin108 shops tested | 723 | 48% | 99.6% | 29% | purity under 99.5%47 failed identity | Shanghai ERP peptide Biotechnology · B, 13 tests |
| Ipamorelin93 shops tested | 448 | 68% | 99.7% | 23% | purity under 99.5%9 failed identity | Reta-Peptide · A, 16 tests |
| Semaglutide73 shops tested | 373 | 67% | 99.8% | 17% | purity under 99.5%11 failed identity | Nuscience Peptides · B, 13 tests |
| CJC-129570 shops tested | 328 | 29% | 98.81% | 37% | purity under 99.5%39 failed identity | Qing Li Peptide · B, 19 tests |
| TB-50060 shops tested | 288 | 38% | 99.3% | 28% | purity under 99.5%33 failed identity | Peptide Partners · B, 13 tests |
| Cagrilintide45 shops tested | 203 | 55% | 99.7% | 19% | purity under 99.5%6 failed identity | Wuhan Wansheng Biotechnology · B, 14 tests |
| Melanotan II45 shops tested | 181 | 63% | 99.67% | 36% | purity under 99.5%5 failed identity | HK Peptides · B, 12 tests |
| PT-14145 shops tested | 156 | 66% | 99.81% | 28% | purity under 99.5%4 failed identity | Polaris Peptides · B, 8 tests |
| MOTS-c21 shops tested | 83 | 34% | 98.9% | 12% | purity under 99.5%8 failed identity | Reta-Peptide · B, 9 tests |
| NAD+21 shops tested | 71 | 24% | 98.55% | 41% | purity under 99.5%8 failed identity | Yimei · C, 4 tests |
| Sermorelin14 shops tested | 49 | 43% | 99.45% | 39% | purity under 99.5%2 failed identity | ZLZ Peptide · C, 5 tests |
| Mazdutide11 shops tested | 29 | 62% | 99.58% | 15% | purity under 99.5% | Peptide-S · B, 4 tests |
| Survodutide7 shops tested | 27 | 50% | 99.44% | 23% | purity under 99.5% | Polaris Peptides · B, 6 tests |
| HGH5 shops tested | 21 | 45% | 99.9% | 43% | purity under 99.5%4 failed identity | Shanghai ERP peptide Biotechnology · C, 7 tests |
| SS-317 shops tested | 19 | 60% | 99.8% | 17% | purity under 99.5%1 failed identity | LiliPeptide · B, 3 tests |
| KLOW8 shops tested | 19 | 68% | 99.85% | 20% | the lab could not confirm it was the labelled peptide3 failed identity | Heman Peptide HM · B, 3 tests |
| KPV7 shops tested | 17 | 18% | 99% | 12% | purity under 99.5% | Homopeptide · B, 3 tests |
| 5-Amino-1MQ7 shops tested | 16 | 60% | 99.6% | 43% | purity under 99.5%1 failed identity | Retalux · B, 3 tests |
| cjc ipa7 shops tested | 11 | 36% | 99.5% | 13% | purity under 99.5%2 failed identity | Crush Research · C, 2 tests |
| Wolverine Stack5 shops tested | 11 | 18% | 99.55% | 57% | purity under 99.5%3 failed identity | Above All Peptides · C, 2 tests |
Peptides with fewer than 10 tests are left out. Fill figures outside ±60% are treated as measurement errors. Research use only. Price per mg by peptide · About independent sample testing
How peptide purity is measured
Purity is measured by HPLC (high-performance liquid chromatography): the share of the sample that is the target peptide rather than synthesis by-products, reported as a percentage. Mass spectrometry confirms identity, that the molecule in the vial is the peptide on the label. A third measurement, the fill, compares the milligrams actually in the vial with the amount printed on it. A vial can be 99% pure and still hold far less peptide than it claims.
What counts as a pass
A sample passes here when it is at least 99.5% pure, holds within 35% of the labelled amount, and the lab confirms its identity. The table shows the pass rate per peptide, so a high median purity with a low pass rate usually means fills or identity are the problem, not purity. How we grade
Underfilled vials by peptide
GHK-Cu vials were underfilled most often: 42% held more than 5% less than the label. Underfilling shows up as a lower real dose per vial, which also raises the true price per mg. Compare the underfilled column with prices on each peptide's vendor page.
Who tests peptides
Results here come from independent lab testing of vials sent in by members of the public, bought by an independent tester, or sent by the shops themselves; each result lists its lab and sender. Testing services such as Finnrick and Janoshik also test peptides for individual buyers. To test a vial yourself, see peptide testing.
How to read a peptide COA
A certificate of analysis (COA) should name the lab, the batch or lot number, the test date, the purity method and the measured amount. Check the batch number against your vial and look the certificate up on the lab's own site. Seven checks before you order