Impact of US and Canadian precursor regulation on methamphetamine purity in the United States

Abstract

US precursor regulations targeting large-scale producers were associated with substantial decreases in continental US methamphetamine purity, while regulations targeting over-the-counter medications had little or no impact. Canada's essential chemical regulation was also associated with a decrease in continental US purity. However, Canada's precursor regulations were associated with purity increases: these regulations may have impacted primarily producers of lower-quality methamphetamine, leaving higher-purity methamphetamine on the market by default. Hawaii's well-known preference for 'ice' (high-purity methamphetamine) may have helped to constrain purity there to a high, attenuated range, possibly limiting its sensitivity to precursor regulation.