What changed at Homopeptide in September, and what the company says prompted it
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
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.
An independent purity determination on cagrilintide material sold by ERP has returned 97.8%, a figure 1.8 percentage points above the number printed on the accompanying certificate, which the supplier had reported against a shorter gradient and a tighter threshold. The analysis was performed by Janoshik on a vial the Journal bought as an ordinary retail customer in August 2025 and posted unopened.
Reported figures across the set were: highest 97.8%, lowest 96.0%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 22 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.
Discrepancies of one to two percentage points between a supplier’s figure and an independent determination are common and usually explicable: a faster gradient resolves fewer impurities, a higher integration threshold discards more small peaks, and a wider solvent-front exclusion window removes early-eluting fragments from the calculation altogether. None of that is misconduct. All of it is invisible unless the method is disclosed.
"Content is the number that matters if you are doing arithmetic with a vial, and content is the number nobody sells," said Lorcan Feeney, analytical services director at an independent laboratory. "Purity is what you can afford. Content is what you need."
ERP’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.
Documentation practice is the only part of vendor quality a buyer can assess before purchase.
Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed is the reagent most of them need.
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.
The report states the gradient, the wavelength and the integration threshold, which is more than most.
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
A reminder that a purity figure is the output of a method, and that methods differ.