Independent analysis puts a QYB semaglutide lot at 98.3%, against 96.3% on the certificate

PeptideMeter has published a purity determination of 98.3% on a 10 mg vial of semaglutide supplied by QYB, against a figure of 96.3% on the certificate that accompanied the vial. The sample was submitted by the Journal in June 2026 as part of a continuing programme of arm’s-length purchasing, and the vendor was told before the order was placed that any result would be published.

The Journal purchased 15 vials from the same lot at retail and had four of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.

The Journal purchased 15 vials from the same lot at retail and had four of them analysed separately, in order to distinguish vial-to-vial variation from method variation. Vial-to-vial agreement was within 0.4 percentage points. Method-to-method disagreement was an order of magnitude larger.

Purity became this trade’s single figure of merit because it is the cheapest measurement to obtain and the easiest to compare. Peptide content, which determines how much drug is actually in a vial, costs several times as much and is quoted as a priced addition by most of the twenty companies in the Journal’s dossier programme rather than carried as a standard release test. Sterility and endotoxin are separate disciplines again, and are neither tested nor claimed.

"The gap that matters is not between the two laboratories, it is between either of them and the certificate," said Havel Novotný, independent laboratory quality manager. "One of those documents states a method. Compare like with like and most of this disappears."

QYB’s dossier has been updated with this determination and with the company’s response to it. The dossier’s ordering box records the lead times, the minimum quantities and what a buyer should ask for at the point of order.