3 independent third-party assays of Tirzepatide, covering 3 vendors.
Measured purity across those assays runs from 99.3% to 99.9%, median 99.6%. The spread is the point: it is variation between lots and between vendors, not a single number that describes the compound.
Assay dates span 2024-08-19 to 2025-11-19.
Tirzepatide carries an evidence grade of A on this site (FDA Approved). Tirzepatide is a first-in-class dual GIP and GLP-1 receptor agonist developed by Eli Lilly, FDA-approved for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound) including severe obstructive sleep apnea in adults with…
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.
| Vendor | Assays | Median measured purity | Most recent |
|---|---|---|---|
| Reta-Peptide | 1 | 99.9% | 2025-11-19 |
| MOB Peptides | 1 | 99.6% | 2024-08-19 |
| Growth Guys Canada | 1 | 99.3% | 2025-01-22 |
Compound profile: Tirzepatide — evidence, mechanism and safety.
Vendors assayed: Reta-Peptide, MOB Peptides, Growth Guys Canada.