Semaglutide research vials: what the lot COA should show

We have not yet published a semaglutide lot report on this site. Before you order, or for a vial you already hold, request the certificate for the exact lot on the testing page; the lot lookup at /verify will show a report only once it is published.

Not every lot has a published certificate. A product page without a published report is not evidence that a lot was tested, and a report for another lot does not describe your vial.

Use this as a checklist for any supplier's certificate, ours included:

1. The lot number on the certificate matches the lot printed on the vial label, character for character.
2. Identity by mass spectrometry: an observed mass (or multiply charged m/z values) consistent with semaglutide's reference mass, not just the word "conforms".
3. Purity by HPLC with the method named (for example HPLC-UV with the detection wavelength) and a chromatogram, reported as area percent.
4. A measured quantity in mg for the vial, separate from the purity figure.
5. The issuing laboratory's name, report or accession number and report date, so the report can be confirmed with the lab.
6. Any extra tests (endotoxin, sterility, water content, counter-ion) listed with their own method and result; a test that is not on the report was not reported.

Semaglutide is a lipidated GLP-1 analogue: a peptide chain carrying a fatty diacid side chain (Lau et al., J Med Chem 2015). With a computed molecular weight of about 4114 g/mol, electrospray LC-MS normally shows it as a set of multiply charged ions rather than one peak at the full mass. A report should state which ions or which deconvoluted mass it observed.

Use the free expected m/z calculator to work out the ions for a given charge state and compare them with the report. "Identity: conforms" with no observed value cannot be checked.

HPLC purity is the share of UV signal in the main peak (area percent). It does not tell you how many milligrams of peptide are in the vial: lyophilized peptides also contain water and counter-ions, so net peptide content is lower than the gross powder weight. A useful COA reports purity and measured quantity separately.

Semaglutide is supplied as a lyophilized (freeze-dried) powder in research vials. Salt form matters for mass balance; see the TFA vs acetate guide for how counter-ions affect weighed amounts.

Keep the sealed vial cold, dry and protected from light, and let it reach room temperature before opening so moisture does not condense on the powder. Our storage and handling guide gives temperatures and sources from peptide manufacturers' published guidance.

This page covers analytical documentation only. It does not give preparation or use instructions; semaglutide sold here is for in-vitro laboratory research only and is not for human or animal use.