Mescaline of the genus "Echinopsis" are technically controlled substances under the Controlled Substances Act, they are commonly sold publicly as ornamental plants. In the United Kingdom, mescaline in purified powder form is a Class A drug. However, dried cactus can be bought and sold legally. Mescaline is considered a schedule 9 substance in Australia under the Poisons Standard (October 2015). A schedule 9 substance is classified as "Substances with a high potential for causing harm at low exposure and which require special precautions during manufacture, handling or use. These poisons should be available only to specialised or authorised users who have
Mescaline biosynthetic pathway involving "m"-"O"-methylation and aromatic hydroxylation. Tyrosine and phenylalanine serve as the metabolic precursors to synthesis of mescaline. Tyrosine can either undergo a decarboxylation via tyrosine decarboxylase to generate tyramine and subsequently undergo an oxidation at carbon 3 by a monophenol hydroxylase or first be hydroxylated by tyrosine hydroxylase to form L-DOPA and decarboxylated by DOPA decarboxylase. These create dopamine, which then experiences methylation by a catechol-O-methyltransferase (COMT) by an "S"-adenosyl methionine (SAM)-dependent mechanism. The resulting intermediate is then oxidized again by a hydroxylase enzyme, likely monophenol hydroxylase again, at carbon 5, and methylated by COMT. The product, methylated