The figures, for anyone assembling their own picture. Numbers worth memorising for this class: Tmax one to three days for the weekly peptides, terminal half-life about a week for semaglutide and about five days for tirzepatide, steady state at four to five half-lives, subcutaneous bioavailability high enough that site choice is irrelevant.

One thing that is still open after Dr.PainCLE’s answer:

Which effects tachyphylax and which persist, because the answer explains why tolerability improves while the appetite effect keeps working?

Dr.NateNeph said:

Numbers worth memorising for this class: Tmax one to three days for the weekly peptides, terminal half-life about a week for semaglutide and about…

There is a second half to this that has not been said yet. 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.

Worth separating that from the pharmacology, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

Reporting back.

Closing this out: the trough rather than the peak explains the pattern I was seeing on day six, which I had been blaming on the vial.

Dr.LeslieOBGYN said:

Start from the measurement rather than the conclusion.

Correct, and worth adding that it is reversible. Nothing being described here is a one-way door, which changes how cautious it is reasonable to be.