11 independent third-party assays of Tirzepatide 20mg, covering 11 vendors.
Measured purity across those assays runs from 99.5% to 99.9%, median 99.8%. The spread is the point: it is variation between lots and between vendors, not a single number that describes the compound.
Assay dates span 2024-09-24 to 2026-04-14.
Manufacturer recorded on the certificates: Tirzeplab, Peptira LLC, Eros Labs.
A certificate of analysis describes the lot that was submitted and nothing else. It is not a guarantee about a later batch, and purity is not identity — a sample can assay clean and still be the wrong compound, or the right compound at the wrong concentration. Vendors with no assay row below have not been tested here, which is not the same as having failed.
2 further assay submitters could not be matched to a vendor profile — the certificate names a mailbox or handle rather than a company — so they are counted in the totals above but not listed below.
| Vendor | Assays | Median measured purity | Most recent |
|---|---|---|---|
| [email protected] | 1 | 99.8% | 2026-04-14 |
| [email protected] | 1 | 99.8% | 2026-04-14 |
| [email protected] | 1 | 99.8% | 2026-04-14 |
| [email protected] | 1 | 99.8% | 2026-04-14 |
| PeptiAtlas | 1 | 99.8% | 2026-04-14 |
| Cocer Peptides | 1 | 99.7% | 2025-12-01 |
| Qing Li Peptide | 1 | 99.6% | 2025-08-11 |
| Peptira LLC | 1 | 99.6% | 2025-06-25 |
| Eros Peptides | 1 | 99.5% | 2024-09-24 |
Vendors assayed: [email protected], [email protected], [email protected], [email protected], PeptiAtlas, Cocer Peptides, Qing Li Peptide, Peptira LLC, Eros Peptides.