Taking the question as asked, rather than the general version of it. Oral semaglutide is absorbed in the stomach with the help of SNAC, which locally raises pH and protects the peptide long enough to cross. That mechanism is fragile: bioavailability is roughly 1% and highly sensitive to gastric contents, so a mouthful of coffee genuinely changes the exposure. This is why the label wants 30 minutes and no more than half a glass of plain water.

Dr.PainCLE said:

Oral semaglutide is absorbed in the stomach with the help of SNAC, which locally raises pH and protects the peptide long enough to cross.

Agreeing with Dr.PainCLE, and the qualification matters more than the agreement. The absorption variability is real, but it partly averages out over weeks — the steady-state trough is less erratic than any single day would suggest. Where it bites is in the first fortnight, when people conclude the tablet does nothing.

tom_AK said:

I switched from injectable to oral semaglutide for travel reasons and the fasting window is proving harder to hold than the injection ever was.

Can confirm the pattern tom_AK describes. Orforglipron is the more interesting oral story because it is not a peptide at all. Being a small molecule it does not need SNAC, does not need the fasting window, and has oral bioavailability in the tens of percent rather than about one.

Adding the clinical framing, because it changes how the question reads. Most of what circulates confidently in this community traces back to one summary of one study, and the qualifier was dropped somewhere in the third retelling.