Oral semaglutide (revision 8)

Oral semaglutide is a tablet formulation of semaglutide co-formulated with the absorption enhancer sodium N-(8-(2-hydroxybenzoyl)amino)caprylate, generally abbreviated SNAC. It was the first orally administered GLP-1 receptor agonist to be approved.^[1]

Peptides are not orally bioavailable: gastric acid and proteases degrade them, and the intestinal epithelium excludes molecules of that size. SNAC addresses both by buffering the local gastric pH and transiently increasing local permeability, allowing absorption across the gastric mucosa itself rather than in the intestine.^[2]

The resulting bioavailability is roughly 0.4–1%, which is why the oral dose is an order of magnitude larger than the injected one in milligram terms. It is also critically dependent on dosing conditions.^[2]

SNAC acts locally and transiently. It raises pH in the immediate vicinity of the dissolving tablet, protecting the peptide from pepsin, and promotes transcellular absorption across the gastric epithelium. The effect is confined to the region around the tablet and to the period during which it dissolves.^[2]

Because absorption occurs at the tablet's location, anything that moves the tablet or dilutes the local environment reduces exposure. This is why the dosing conditions — fasting, no more than 120 mL of water, and a further 30 minutes without food, drink or other oral medicines — are part of the product rather than advice.^[1]

Deviations change exposure severalfold, and between-individual variability is correspondingly larger than for the injected formulation.^[2]

Approved for type 2 diabetes, oral semaglutide reduces glycated haemoglobin by roughly 1.0–1.4 percentage points at the studied doses, with modest weight reduction — smaller effects than weekly injected semaglutide at its obesity dose.^[1]

Its advantage is route. For someone unwilling or unable to inject, an oral option changes what treatment is available at all, and this is the axis on which it competes rather than on effect size.^[3]