Does splitting a 5 mg weekly dose of ecnoglutide across two administrations change anything?

The specifics, since they change the answer: 5 mg · ecnoglutide.

I would like the mechanism, because I want to be able to reason about the cases nobody has written about.

I have tried to reason it out from first principles and got to two contradictory conclusions.

So what is the mechanism, and how well established is it?

Two administrations of 2.5 mg instead of one of 5 mg — the same 5 mg a week either way. Total weekly exposure is unchanged; what changes is the peak-to-trough ratio, and for an agent with a half-life measured in days the trough barely moves because the dosing interval is already short relative to it. The arithmetic is the easy part: 5 ÷ 2 = 2.5. Whether it is worth doing is a pharmacokinetic question, and nothing here is medical advice.

The honest answer is that reported tolerability benefits are real to the people reporting them and are not well explained by the exposure profile.

For a thirteen-hour half-life agent dosed daily, τ/t½ is about 1.8 and the swing is nearly fourfold, which is why the daily agents feel peakier and why splitting them would have more effect.

Splitting that same weekly dose into two half-doses at 3.5-day intervals gives τ/t½ = 0.5 and a peak-to-trough ratio of about 1.41. The profile is flatter, and the difference between a 2-fold and a 1.4-fold swing is not obviously perceptible.

The caveat is that no split schedule has been evaluated in a trial, so the whole discussion is inference plus report.

Slower titration has evidence; splitting has anecdote. Prefer the first.