Scientists Figured Out a Standard Measure For Cannabis Use

OG article by Jess Cockerill

January 19, 2026

Researchers at the University of Bath have developed a standardized THC unit system for cannabis use, similar to alcohol's standard drinks, to promote informed consumption and reduce risks of cannabis use disorder (CUD). As legalization expands globally, harm reduction becomes critical for public health. Senior author Tom Freeman emphasized helping users make better choices amid rising availability. CUD risks include dependence, mental health issues, tolerance, impaired cognition, and social/financial problems. Measuring use has been inconsistent due to past illegality and variable potency—THC levels have risen dramatically over time, amplifying risks. Analyzing CannTeen study data from 150 London users over 12 months, the team quantified potency: a 0.45g joint of high-THC herbal cannabis equals about 12.78 THC units, versus 3.78 for weaker seeded varieties. Guidelines suggest adults limit intake to no more than 8 THC units weekly to minimize CUD odds—70% exceeding this reported disorder symptoms. Lead author Rachel Lees Thorne stressed harm reduction: abstinence is safest, but for ongoing users, clearer metrics aid risk reduction. Experts like psychiatrist Marta Di Forti praise the approach as a valuable foundation, despite cannabis containing over 144 cannabinoids, enabling moderation guidance and better research. Published in Addiction, the framework empowers consumers and supports evidence-based policies in legal markets.