How to read a tirzepatide certificate of analysis

A tirzepatide certificate of analysis answers four questions about one lot: is the material tirzepatide, how much of what the detector sees is the main peptide, how many milligrams are in the vial, and does it pass the screens for endotoxin, elemental impurities and sterility. All ten certificates on file for tirzepatide come from one testing laboratory, Bioviridian Inc., and every size, 10, 20, 30, 60 and 100 mg, has a current one, issued on August 28, 2026. This guide reads them line by line, as of October 15, 2026.

What is on a tirzepatide certificate?

The 20 mg certificate, COA7623 for lot TIR20-0803, shows the layout all five current certificates share:

The laboratory received the sample on August 11, 2026 and issued the certificate on August 28. The sample name on the certificate is "Tirzepatide 20mg", submitted by the supplier.

What does the identity line prove?

That the mass the laboratory measured matches tirzepatide's. Tirzepatide's formula is C225H348N48O68, with a molecular weight of 4,813.53 on its FDA label and a monoisotopic mass of 4,810.52. An electrospray instrument sees the molecule carrying several protons at once, so the peaks appear at the mass divided by the charge:

These are arithmetic, not certificate figures: (M + n × 1.00728) / n. At this size the monoisotopic peak is not the tallest in its isotope envelope; the tallest sits two or three daltons higher, so on a resolved spectrum the monoisotopic value is found at the low-mass edge. Mass is also what separates tirzepatide from its neighbours: semaglutide near 4,114 and retatrutide near 4,731 are far enough away that no working instrument confuses them, as tirzepatide vs semaglutide sets out.

The current certificates use LC-MS/MS; the earlier lots used MALDI-MS. Both report "conforms" rather than the measured mass itself, so the certificate tells you the identity check was passed, not the number it was passed with.

How pure is each lot?

Purity is the main peak's share of everything that absorbs light at 214 nm. It does not say which peptide the main peak is; that is the identity line's job. A high purity on a sample that failed identity would describe a pure sample of the wrong material, which is why the two lines are read together.

Is the content line the same as purity?

No. Purity is a ratio; content is an amount. The content line is the laboratory's quantitation of tirzepatide in the vial, in milligrams, against the size on the label. Every current lot measured slightly above its label, between 101.8 and 103.9 percent. The certificates do not report net peptide content as a percentage of powder weight, so they do not separate the peptide from counter-ions and residual water; net peptide content explains what that figure would add.

What about the earlier lots?

Five earlier certificates are also on file: TIRZ10-0318, issued April 3, 2026; TIR10-0528, TIR20-0528 and TIR600-0528 (a 60 mg lot; the number is as printed on the certificate), issued June 17, 2026; and TIR100-0616, issued July 7, 2026. Each reports 99.8 or 99.9 percent purity by RP-HPLC, identity by MALDI-MS that conforms, and measured content between 101.0 and 110.6 percent of the label, the highest being the March 10 mg lot at 11.06 mg. The March certificate is the only one without a heavy-metals or sterility line. Earlier lots stay listed so a vial bought from one of them can still be checked.

What a tirzepatide certificate does not say

• It is not a second laboratory's opinion. Every certificate here is from one laboratory, on a sample the supplier submitted.
• It does not report the measured mass. Identity reads "conforms".
• It does not sequence the peptide. Mass identity is strong evidence for a 4.8 kDa peptide, not a residue-by-residue read.
• It says nothing about use in a person. It describes a laboratory material, and the material is sold for research only. A certificate for research tirzepatide is not a release document for Mounjaro or Zepbound, which are made and tested under their FDA applications; is tirzepatide FDA approved? dates those approvals.

Every certificate listed here links to its own page with the laboratory's verification number from the tirzepatide research reference. The general method is in how to read a certificate of analysis.

Common questions

What should the mass spectrum of tirzepatide show?

Peaks for tirzepatide carrying several protons: near m/z 1,604.5 for three, 1,203.6 for four and 963.1 for five, from the monoisotopic mass of 4,810.52. These are arithmetic on the formula, not values printed on the certificates.

Why is measured content above the label?

The certificate reports what the laboratory measured; it does not say how the vial was filled. The five current lots measured between 101.8 and 103.9 percent of their labelled size.

Does every tirzepatide size have a certificate?

Yes. All five sizes, 10, 20, 30, 60 and 100 mg, have a current certificate issued on August 28, 2026.

Who tested these lots?

Bioviridian Inc., a third-party testing laboratory, on samples submitted by the supplier. Each certificate carries the laboratory's own number, which can be checked with the laboratory.

Sources

• MOUNJARO (tirzepatide) prescribing information, section 11, revised 8/2026, DailyMed
• Tirzepatide, PubChem CID 156588324, National Library of Medicine
• Tirzepatide, UNII OYN3CCI6QE, FDA Global Substance Registration System
• USP <85> Bacterial Endotoxins Test, United States Pharmacopeia
• USP <71> Sterility Tests, United States Pharmacopeia