One concrete data point for the thread. Worth knowing that the injection site changes very little. Abdomen, thigh and upper arm are bioequivalent for semaglutide, so a site change is not a plausible explanation for a bad week.
A narrower follow-up, since the general answer is now clear:
How much of the between-person variation is pharmacokinetic and how much is just adherence measured badly?
hank_denver said:Worth knowing that the injection site changes very little.
There is a second half to this that has not been said yet. The dose-response is real but shallow at the top. Across STEP 1 and STEP 4 the gap between 1.7mg and 2.4mg is a couple of percentage points of body weight on average, and the average is carrying a wide spread — plenty of people at 1.7mg sit above the 2.4mg mean. If a dose is working and tolerable, "working" is the relevant variable, not "maximal".
PeptideMeter — Independent Peptide Analytics
Community-driven peptide testing and vendor rating platform. Transparent results. Unbiased analysis. Trusted by thousands.
View ResultsOP back with an update, since a thread like this is useless without one.
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.
PharmD_Rodriguez said:The dose-response is real but shallow at the top.
Agreeing with PharmD_Rodriguez, and the qualification matters more than the agreement. Steady state is the thing most people miss. The terminal half-life is about a week, so every dose step takes four to five weeks to fully express itself. Judging a step at day ten is judging the ascent, not the plateau, and it is the single commonest reason people escalate before they needed to.