Semaglutide pharmacokinetics — half-life, Tmax, steady state modeling

Adding the numbers, since they settle part of this. 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.

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

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?

raj_cambridge 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. 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.

Ask again with the specifics and you will get a better answer than this one.

Reporting back.

Update — tachyphylaxis to the gastric effect, persistence of the appetite effect. Two curves, and I had been watching the wrong one.

Dr.ObesityLA said:

Steady state is the thing most people miss.

That holds for the injectable. The oral formulation has different absorption behaviour and the dose numbers are not interchangeable, which is worth saying out loud because people quote them as if they were.