What Dose of Methamphetamine Do Regular Consumers Use Daily? Estimating Oral Amphetamine Milligram Equivalents

Abstract

OBJECTIVES: The purity, accessibility, and affordability of illicit methamphetamine have increased in recent decades, which has been linked to rising rates of methamphetamine-involved overdoses, psychosis, cardiovascular events, and other health consequences. Nevertheless, information about the quantity of methamphetamine used by regular consumers has been limited, despite the potential clinical utility of exposure quantification. METHODS: From August 2024 to April 2026, self-reported daily methamphetamine consumption was assessed among n = 94 individuals in Los Angeles County. Methamphetamine samples (n = 256) were analyzed for purity using liquid chromatography-mass spectrometry. Bioavailability by route of administration and stimulant equivalency were obtained from the literature. A simulation model leveraging bootstrapping with 1,000,000 draws was used to estimate oral amphetamine milligram equivalents (AME). RESULTS: The average reported methamphetamine consumption was 1.09 g daily (95% prediction interval: 0.07-4.00). Average purity was 84.52% (95% PI: 14.90%-100.00%). Given estimated average bioavailability of 66.41% (95% PI: 39.35%-85.24%), the average consumer used an estimated 1432.54 AME daily (95% PI: 35.74-6973.05). CONCLUSIONS: We estimate that consumers of methamphetamine in Los Angeles use an average daily stimulant dose (nearly 1500 oral AME) about 25-fold higher than the maximum typical recommended clinical dose of mixed amphetamine salts (60 mg). This may help contextualize why prescription stimulant treatment trials using substantially lower doses have shown limited efficacy. Given this high dose, these findings shed light on the rising incidence of methamphetamine-related sequelae, such as psychosis, cardiovascular complications, and sudden death. Although exposure quantification is commonplace for alcohol and tobacco use disorders, uncertainties in illicit drug markets have complicated this practice for most illicit drugs. This study supports leveraging emerging information from drug checking programs so that clinicians can approximate exposure quantification.