SmokeLESS tablets contain the active ingredient, varenicline (as the tartrate salt), which is a partial agonist selective for (alpha)4(beta)2 nicotinic acetylcholine receptor subtypes.

Varenicline, as the tartrate salt, is a powder which is a white to off-white to slightly yellow solid with the following chemical name: 7,8,9,10-tetrahydro-6,10-methano-6H-pyrazino[2,3-h][3]benzazepine,(2R,3R)-2,3-dihydroxybutanedioate (1:1). It is highly soluble in water.

Varenicline tartrate has a molecular weight of 361.35 Daltons, and a molecular formula of C13H13N13 • C4H6O6. The chemical structure is:

SmokeLESS is supplied for oral administration in two strengths: a 0.5 mg coated tablet and a 1 mg coated tablet.