Sublingual

Sublingual administration places a substance under the tongue so it can be absorbed through the thin, blood-rich tissue on the floor of the mouth.

The area beneath the tongue drains into veins that lead directly to general circulation, bypassing the liver's first-pass metabolism. Compounds absorbed this way can act faster and more completely than when swallowed. Sublingual products include tablets, films, sprays, and oil drops that are held in place for a period before the remainder is swallowed. Absorption depends on the compound's solubility, the formulation, and how long it stays in contact with the tissue.

Oil-based CBD tinctures are commonly labeled for sublingual use. Because cannabidiol is fat-soluble and oils do not readily cross the moist mouth lining, a substantial portion of a sublingual oil is likely swallowed and absorbed orally, so the practical difference from swallowing is smaller than marketing often suggests. Human pharmacokinetic data on sublingual CBD oils are limited. Readers meet this term on tincture labels, and it is often confused with buccal, which uses the cheek lining instead.