Vol. 3, No. 6 — June 2026Independent since 2024

TheCompound Journal

Reporting on incretins, compounding & the peptide supply chain

A monthly journal of record.
30 issues · 32 contributors
Not medical advice. We sell nothing.

Testing Dispatch

Independent analysis puts a QSC orforglipron lot at 97.3%, against 94.6% on the certificate

A reminder that a purity figure is the output of a method, and that methods differ.

A peptide content determination commissioned by the Journal on a 2 mg orforglipron vial from QSC has returned 93% of the labelled mass, the balance being the counter-ion and residual water that every lyophilised salt carries. Chromatographic purity on the same vial was above 97.3%. The two numbers measure different things, and this is one of the few certificates in the trade to print both.

The Journal purchased 13 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 wider context is that material sold for research use carries no regulatory release specification in any jurisdiction the Journal has examined. A certificate is a commercial document, not a compliance one, and its content is whatever the issuer chooses to put on it. That is the gap independent testing fills, and it fills it imperfectly.

"The gap that matters is not between the two laboratories, it is between either of them and the certificate," said Dr Sirichai Boonmee, peptide chemist, Chulalongkorn University. "One of those documents states a method. Compare like with like and most of this disappears."

QSC’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.

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