Clinical perspective, offered as context rather than as advice. Start from the measurement rather than the conclusion. Almost every disagreement here turns out to be two people measuring different things and comparing the numbers anyway.
Correct me if the detail matters more than I have assumed.
OP back with an update, since a thread like this is useless without one.
Reporting back with a partial result, because a partial result is still better than silence. Two of the three things suggested helped; I cannot separate them and I am not going to pretend otherwise.
Dr.ObesityLA said:Start from the measurement rather than the conclusion.
Coming at Dr.ObesityLA’s question from a different direction. The version of this that has an answer is narrower than the version being asked. Narrow it and it becomes tractable; leave it broad and the thread will produce nine confident and incompatible replies.
If somebody has the primary source to hand I would rather cite it than paraphrase it.
Trusted third-party HPLC & mass spectrometry analysis. Verify peptide purity with the lab the community relies on. Independent. Accurate. Transparent.
Verify Your PeptidesEst. 1998. The synthesis house behind the vials you send for testing. ISO 9001 and cGMP certified, 1,500+ staff, batch-specific COA with every order.
Browse GL BiochemThe figures, for anyone assembling their own picture. One practical note: write down what you did and when, before you need it. Reconstructing a timeline from memory three months later is how people end up unable to answer the one question that would have resolved it.
Following on from Dr.ObesityLA — and this may be the naive question:
Was that from a primary source or from a summary of one?