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 at the two meta positions with respect to the alkyl substituent, experiences a final methylation at the 4 carbon by a guaiacol-O-methyltransferase, which also operates by a SAM-dependent mechanism. This final methylation step results in the production of mescaline. Phenylalanine serves as a precursor by first being converted to -tyrosine by L-amino acid hydroxylase. Once converted, it follows the same pathway as described above. Mescaline was first synthesized in 1919 by Ernst Späth from 3,4,5-trimethoxybenzoyl chloride. Subsequent to this, numerous approaches utilizing different starting materials have been developed. Notable examples include the following: Tolerance builds with repeated usage, lasting for