Demethylation is the chemical process resulting in the removal of a methyl group (CH₃) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms.

Demethylation is the chemical process resulting in the removal of a methyl group (CH₃) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms.