Semaglutide pharmacokinetics — anyone have experience?

Dr.BariatricHTX said:

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

This answered a question I did not know how to ask. Adding it to my notes with a link back to this thread.

Adding the clinical framing, because it changes how the question reads.

lisa_labSD said:

...but the FDA says semaglutide...

Interesting point. I want to add some regulatory nuance: the FDA labeling reflects the specific clinical trial data submitted for approval. Real-world clinical practice often extends beyond the FDA label based on emerging evidence and clinical judgment.

Example: semaglutide was first approved for diabetes (Ozempic), then obesity (Wegovy). The molecule didn't change — our understanding of its applications expanded. Similarly, semaglutide may evolve as more data accumulates.

Dr.ObesityLA said:

Albumin binding above 99% is the whole reason weekly dosing works, and it is also why the trough matters more than the peak.

Pushing back on Dr.ObesityLA here. The trial means are being read too generously in this thread. STEP populations were selected, supported, and titrated by protocol, and the real-world curves are consistently a few points worse. That difference is not noise, it is what happens when you remove the study infrastructure.

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

Moderator note: two posts asking for a source have been merged into one. Please search the thread before asking again. Thread quality here is what the rules are for. Keep it up.