[Meta] the regulatory rule is doing its job and people should stop complaining
the regulatory rule is doing its job and people should stop complaining. Nothing about this affects the ranking maths, before anyone asks.
Research-use-only material is not approved for human use. In this board that is not a formality — it is the reason the clinical evidence base is as thin as it is.
The published literature is overwhelmingly preclinical, largely in rodent models. Translating a rodent result into a human expectation is not a small step, and almost every confident claim here takes it silently.
Short peptides in solution are subject to hydrolysis and, depending on sequence, oxidation. Storage state and time in solution are practical variables that this board almost never discusses.
I will update this if the picture changes rather than quietly leaving it up.
best — the order this archive was captured in
Why identity, not purity, is the test to buy here.
This is a short peptide with a published sequence. Synthesis is not difficult, which means the market is wide and the analytical question shifts. A high area-percent figure tells you the sample is homogeneous; it does not tell you the homogeneous material is the sequence you ordered.
Mass spectrometry, with the theoretical mass alongside the measured one, converts a purity claim into an identity claim. It costs a little more and it answers the question that actually matters. Ask for it, and ask suppliers whether they can provide it before you order — the answers are informative in themselves.
Correction: that study was in rodents. Worth stating explicitly since the thread has been reading it as clinical.
stability in solution is the practical question nobody asks
Yes — the rodent literature is real and it is rodent literature. The gap to a human claim is enormous and it gets crossed in one sentence here.
research-use-only means not approved for human use, and here that covers everything
research-use-only means not approved for human use, and here that covers everything
marit_sandvik is right that a pure something-else is still something else.
Every claim I could trace in this board went back to about four papers. That was a sobering afternoon.
Asked WWB for the theoretical mass alongside the certificate and they sent it without asking why.
Paid for identity confirmation rather than just purity for the first time here. Worth it, and it is not the default on most certificates.
a fifteen-residue peptide is easy to make and easy to make badly
Agreed — cheap to make is a double-edged fact and it explains a lot about this corner of the market.
I would not extrapolate a mechanism from a model system to a person in one step, which is what that comment does.