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Reporting a good result: why nobody bothers and why they should

Sourcing › Vendor reports third-party testing Janoshik Analytical certificate of analysis batch & lot numbers

d.achebeTL2 Moderator14 Jan 2026#1

Reporting a good result: why nobody bothers and why they should — setting out what I have, and where I think it stops being reliable.

Structured report rather than an opinion, following the format the maintainers asked for.

Compound: semaglutide
Independent testing: PeptideMeter
Method as reported: reversed-phase HPLC, 280 nm
Result: 96.4% area
Certificate figure for the same lot: 98.6%

I am not drawing a conclusion about the supplier from one lot and I would ask that nobody else does either. I am adding a data point to a record.

19 likes 6mo

s.girardTL2 Moderator7 May 2026#2

Picking up the opening post: that is the part I would want checked first.

Dosing and purity: a vial that is 99% pure might contain 80% of its label claim if the other mass is water, counter-ion, and excipient. Purity and content are different. Both matter for different reasons.

3 likes 3mo

logbook_erinTL3Regular27 Jul 2026#3

On the opening post — agreed on the reasoning, with one qualification.

Pattern across lots: a single result is a data point. Three or four results from the same supplier showing a consistent pattern becomes a record worth discussing. Two results that disagree might just be measurement variation.

0 likes 17h

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Sponsored Janoshik Analytical — independent third-party testingHPLC purity and mass-spectrometric identity on submitted samples, reported with the method stated. The laboratory most often cited in this community’s verification records.Independent testing → Sponsored GL Biochem (Shanghai) Ltd. — synthesis, directFounded 1998. ISO 9001 and cGMP certified, over 1,500 staff and 200-plus patents. Custom peptide synthesis and amino acid derivatives, with a batch certificate on every order.Custom synthesis →