MDMA risks cannot be calculated from sex alone

The key question

NIDA describes cardiovascular, temperature, and neurobehavioral effects that warrant concern across adults. Sex or body size alone cannot turn an unknown product into a predictable exposure. Medicines, health conditions, activity, temperature, and other substances matter, while evidence does not provide a personal safety calculator. Comparisons between women and men must specify what was measured and in whom; an average difference is not a safe-use rule for an individual. [1]

What the evidence can and cannot establish

MDMA has acute physiological effects as well as psychological effects. Research participants, product composition, setting, and other substance use influence what a study can tell us. Observational research cannot always separate MDMA from sleep loss or additional drugs. Controlled research does not recreate every real-world exposure. These distinctions matter when a claim moves from a mechanism in the brain to a promise of treatment or a prediction of long-term harm. [1]

Putting it into practice

Do not use sex-based internet dosing formulas as a safety guarantee. [1]

Small or selected study populations cannot establish safety for adolescents, pregnancy, or all products. [1]