Independent analysis puts a GGPeps cagrilintide lot at 99.2%, against 95.1% on the certificate

Medutest has published a purity determination of 99.2% on a 5 mg vial of cagrilintide supplied by GGPeps, against a figure of 95.1% on the certificate that accompanied the vial. The sample was submitted by the Journal in March 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 1900 vials from the same lot and had 18 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.

Batch variance rather than vendor quality is the recurring finding of this programme. Across the 18 determinations the Journal has commissioned to date, within-vendor spread has been wider than between-vendor spread for two thirds of the companies tracked, which is an argument against rating any supplier on a single number.

"Content is the number that matters if you are doing arithmetic with a vial, and content is the number nobody sells," said Havel Novotný, independent laboratory quality manager. "Purity is what you can afford. Content is what you need."

GGPeps’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.