How does HJ compare to Shanghai Wibson Biotechnology on documentation quality?

Details up front: HJ · Shanghai Wibson Biotechnology.

I would like the axes of comparison first and the recommendation second.

I have tried the first option and it works; the question is whether the second is better rather than merely different.

Under what conditions does the answer flip?

Answering this needs the axis. A supplier that is best on paperwork and a supplier that is best on price are both correct answers to different questions.

Compare documentation on a fixed checklist rather than by impression: lot specificity, method section, chromatogram availability, quantified content, water and counter-ion figures, and whether the code is on the vial.

To compare properly: order the same compound at the same nominal strength from each supplier, submit all samples to the same laboratory in the same submission if possible, and ask for the same test set on each.

No supplier on this site pays for its position, and the storefront links are marked nofollow and sponsored.

One laboratory, one method, one submission. Otherwise it is not a comparison.

Answer first: comparing suppliers is only meaningful if the comparison holds the laboratory, the method and the compound constant, and most published comparisons hold none of them.

Sample size matters. One order each is an anecdote about six vials; three orders each over a year is the beginning of a comparison.

Publish the method with the result. A comparison without the laboratory named and the submission dates given is not reproducible by anyone.

Inter-laboratory spread on identical peptide material is routinely half a per cent to a per cent by RP-HPLC, which is the noise floor for any cross-laboratory comparison.

Nothing here is medical advice, and research-use compounds are not approved for human use.

Compare content, not purity. Purity clusters and content does not.

edited 24 Nov 2024 by nkem_obiora — reworded for clarity after a comment

This is the question where methodology matters more than the conclusion.

Submitting to different laboratories introduces a method difference that commonly exceeds the supplier difference. Gradient slope alone can move a reported purity figure by a per cent in either direction.

The ratings on this site are a community opinion average on a ten-point scale and are not reconciled with any other community's figures.

Price per milligram of measured peptide, not per milligram of label claim.

The short version: same compound, same laboratory, same method, ideally same week — otherwise you are comparing laboratories rather than suppliers.

Cost per milligram of actual peptide is the honest price comparison, which means dividing by measured content rather than by label claim.

Content assay results across the published datasets vary considerably more between suppliers than purity does, which makes content the more discriminating axis.

Name the laboratory and the dates or the comparison cannot be reproduced.

edited 23 Dec 2024 by tobias_maartens — added a caveat about sampling