One concrete data point for the thread. For anyone assembling their own picture: Tmax is one to three days, terminal half-life about 165 to 170 hours, steady state at four to five weeks, and subcutaneous bioavailability near 89%. Those four numbers explain most of the questions people ask about timing.

One thing that is still open after paige_pharma’s answer:

How much of the between-person variation is pharmacokinetic and how much is just adherence measured badly?

wendy_avl said:

For anyone assembling their own picture: Tmax is one to three days, terminal half-life about 165 to 170 hours, steady state at four to five weeks, and…

Adding the part of the answer the thread has not reached. The mechanism that matters here is not stomach emptying, it is central. GLP-1 receptor agonism in the arcuate nucleus stimulates POMC neurons and suppresses AgRP/NPY signalling, which is why the effect is appetite and food salience rather than physical fullness. Delayed gastric emptying largely tachyphylaxes over the first months; the appetite effect does not.

OP 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.

Dr.PulmRoch said:

The mechanism that matters here is not stomach emptying, it is central.

Dr.PulmRoch has the substance of this right. The condition it depends on is worth stating. Albumin binding above 99% is the whole reason weekly dosing works, and it is also why the trough matters more than the peak. People who dose late are not losing a peak, they are letting the trough fall, and the appetite effect tracks the trough.