PeptideMeter result on a Changsha mazdutide lot lands 1.3 points above the supplier’s stated figure
A reminder that a purity figure is the output of a method, and that methods differ.
TheCompound Journal
Reporting on incretins, compounding & the peptide supply chain
Testing Dispatch
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
VendorInvestigate has published a purity determination of 95.7% on a 30 mg vial of orforglipron supplied by SSA, against a figure of 92.2% on the certificate that accompanied the vial. The sample was submitted by the Journal in July 2024 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 11 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.
Reported figures across the set were: highest 95.7%, lowest 92.2%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 16 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Four independent services — VendorInvestigate, Medutest, and the two others operating in this market — carry the analytical burden for a trade that has no release-testing obligation of its own. Each is paid by whoever submits the sample, which is usually the vendor. The Journal’s position is that a submitter-pays model is workable but that its incentive structure has to be stated whenever a result is quoted as verification.
Dr Emiko Tanabe, mass spectrometrist, was more cautious. "One lot tells you about one lot. I would not draw a conclusion about a company from a single determination, and I would not let a company draw one either."
SSA’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.
A reminder that a purity figure is the output of a method, and that methods differ.
A document is only as good as the chain that connects it to the material, and most chains here are two or three links longer than the paperwork admits.
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Follow the resin, not the catalogue.
The supplier confirmed the determination and supplied the method behind its own figure inside a week.
The result is unremarkable. What the report states alongside it is not.