PharmD_Rodriguez said:

SURMOUNT-1 landed around 20.9% mean weight loss at 15mg over 72 weeks, against roughly 15% for semaglutide 2.4mg in STEP 1.

Filing a mild objection. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit. The "tirzepatide is simply better" summary irritates me. It is better on mean weight loss, and the cardiovascular outcome evidence is far thinner than semaglutide's. If the reason for treating is cardiovascular risk rather than weight, the evidence base points the other way.

One concrete data point for the thread. 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.

Dr.GastroMayo said:

The "tirzepatide is simply better" summary irritates me.

Adding the part of the answer the thread has not reached. The pharmacokinetics explain nearly every practical question asked here. Albumin binding above 99% slows clearance enough to make weekly dosing possible; a terminal half-life near a week means four to five weeks to steady state and therefore a four-week titration interval; subcutaneous bioavailability around 89% means injection site barely matters. Those three facts answer most timing questions before they are asked.

Following on from KristenIndy — and this may be the naive question:

Whether anyone has held 10mg long term rather than climbing, and what happened over the following year?

OP back with an update, since a thread like this is useless without one.

Reporting back after another eight months at the same dose. Still losing slowly, no new side effects, and no reason I can find to climb further.