PeptideMeter result on a Zhuhai mazdutide lot lands 2.7 points below the supplier’s figure

An independent purity determination on mazdutide material sold by JEEP has returned 98.8%, a figure 2.7 percentage points below the number printed on the accompanying certificate. The analysis was performed by PeptideMeter on a vial the Journal bought as an ordinary retail customer in February 2025 and posted unopened.

Reported figures across the set were: highest 98.8%, lowest 95.6%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 4 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Reported figures across the set were: highest 98.8%, lowest 95.6%, median close to the midpoint of the two. Every report in the set stated a detection wavelength, and 4 of them stated an integration threshold. The Journal has asked the laboratory to publish thresholds on all reports as a matter of routine.

Batch variance rather than vendor quality is the recurring finding of this programme. Across the 4 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 Rowena Ashcombe, community pharmacist and diabetes educator. "Purity is what you can afford. Content is what you need."

JEEP’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.