Medutest result on a Qingdao dulaglutide lot lands 1.4 points below the supplier’s figure

Medutest has published a purity determination of 99.3% on a 2 mg vial of dulaglutide supplied by Homopeptide, against a figure of 95.4% on the certificate that accompanied the vial. The sample was submitted by the Journal in October 2025 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.

Reported figures across the set were: highest 99.3%, lowest 95.4%, 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.

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.

Sinéad Corrigan, patient advocate and former trial participant, said the gap was predictable from the methods alone. "You can reconstruct almost the whole difference from the integration threshold. What you cannot reconstruct is why anyone thinks a number without a threshold is comparable to a number with one."

Homopeptide’s dossier has been updated with this determination and with the date of the request for comment. The dossier’s "what we could not verify" box records the questions still outstanding.