4 evidence-graded facts. Click any card for the full summary and sources.
THC metabolites are fat-soluble and linger for days (occasional use) to weeks (daily use) in urine. Roadside and workplace tests detect exposure, not impairment — one of the hardest unsolved problems in cannabis policy.
Consumption & Dosing STRONG EVIDENCEPeak effects from edibles arrive far later than smoking (minutes). The classic bad experience is re-dosing at minute 45 because "nothing happened" — then both doses land together. The single most protective rule with edibles is: wait two full hours before taking more.
Consumption & Dosing MODERATE EVIDENCEVaporizers heat cannabis below combustion, and studies show drastically reduced carbon monoxide and tar byproducts versus smoking, with similar THC delivery. "Reduced harm" is accurate; "harmless" is not — long-term data is thin, and vape liquids are a separate, riskier category.
Consumption & Dosing STRONG EVIDENCEStudies sealing non-smokers in small unventilated chambers with heavy smoke produced detectable THC metabolites and mild effects. In ventilated real-world conditions, positives were rare and below standard testing thresholds. The "contact high" is real but requires genuinely extreme exposure.
Consumption & Dosing