Why oral semaglutide needs an absorption enhancer at all — one year on

Why oral semaglutide needs an absorption enhancer at all — one year on — that is the question, and I have not found it answered plainly anywhere I have looked.

I have seen SCALE (N Engl J Med, 2015) cited in support of a claim I do not think it supports, twice this month, so I would like to work through what it actually shows.

My reading is that the trial is sound for its own question and is being stretched to answer a different one. I might be wrong about that, which is why this is a topic rather than a correction.

What I would like from this discussion: someone who disagrees with me to say why, with the section of the paper they are relying on.

Oral versus injectable exposure: comparing a 14 mg oral dose with a 0.5 mg injectable dose is comparing apples to a different fruit. The oral bioavailability is low enough that dose numbers are an order of magnitude different and not directly comparable.

Trial adherence in an oral trial with strict administration requirements is genuinely worse than trial-published data often suggests. That is why the exposure variability in oral formulations is mentioned repeatedly in the discussions here.

SNAC is the sodium N-(8-[2-hydroxybenzoyl]amino) caprylate, an absorption enhancer that transiently raises local pH in the stomach and promotes gastric mucosal absorption. Without it, oral bioavailability of semaglutide would be too low for clinically useful dosing.

Coming back to post #13, because the follow-up matters more than the original answer.

Dose numbers for oral formulations are not comparable to injectable ones. The 14 mg oral dose is not equivalent to any injectable dose in the traditional comparison sense. They are different formulations with different pharmacokinetics and cannot be put on the same scale.