A narrower follow-up, since the general answer is now clear:
What would you measure differently if you were starting again?
Reporting back.
Following this thread I went back and re-read the extension data properly. The point about trough rather than peak explains the pattern I was seeing on day six, which I had been blaming on the vial.
BethLabQueen said:If you are going to change something, change one thing and give it long enough to express itself.
True, with the qualification that this is a self-selected group. The people for whom it did not work post less, and that shapes everything we think we know.
Worth separating that from the pharmacology, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.
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 BiochemFound this through search years later and it is still the best discussion of the question, so adding one thing. The boring version of this is the one that works, and the boring version is: measure a baseline, change one variable, wait, measure again under the same conditions. Nobody wants that answer and it is still the answer.
From the other side of the consultation, briefly. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.