MeTh BreakDown

Following TexT Frum: https://www.quora.com/Does-methamphetamine-break-down-into-phetamine-after-two-days-for-drug-test

Methamphetamine is double methylated phenylethylamine.

Methamphetamine actually breaks down and metabolizes into amphetamine.

Amphetamine is scientifically known as methylated phenylethylamine.

Methylation, the transfer of a methyl group (―CH3) to [ a chemical ] compound. Methyl groups may be transferred through addition reactions or substitution reactions; in either case, the methyl group takes the place of a hydrogen atom on the compound. Methylation can be divided into two basic types: chemical and biological.