Stated plainly: SSA · Tianjin Finder Chemical.
The comparison I want does not seem to exist anywhere in a form I can evaluate.
I have read the arguments for each and they do not engage with each other.
What does each option buy me, and what does it cost me?
The relevant point is that two competent laboratories disagree by half a per cent on identical material, which is larger than most of the differences people argue about.
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.
Content is the more discriminating measurement than purity for supplier comparison, because purity clusters tightly among competent suppliers and content does not.
Content assay results across the published datasets vary considerably more between suppliers than purity does, which makes content the more discriminating axis.
The caveat is that a comparison is a snapshot of the lots compared, and lots change.
Price per milligram of measured peptide, not per milligram of label claim.
Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.
Browse resultsAnswering 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.
Sample size matters. One order each is an anecdote about six vials; three orders each over a year is the beginning of a comparison.
Cost per milligram of actual peptide is the honest price comparison, which means dividing by measured content rather than by label claim.
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.
Use a fixed documentation checklist rather than an impression.
Ratings on this site are ours alone and are deliberately not reconciled with anyone else's.
Lead time and lane behaviour are supplier properties too and are easier to compare than analytical ones, because they need no laboratory at all.
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.
One laboratory, one method, one submission. Otherwise it is not a comparison.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.