7 evidence-graded facts. Click any card for the full summary and sources.
Raphael Mechoulam's team in Israel isolated and synthesized Δ9-THC in 1964 — and CBD a year earlier. Despite cannabis being used for millennia, its chemistry is a modern discovery: younger than the Beatles.
THC STRONG EVIDENCETHC partially activates CB1 receptors rather than fully switching them on. This partial activity is one reason cannabis has a wide safety margin compared to full-agonist synthetic cannabinoids ("spice"), which can be lethal — a critical distinction often lost in public debate.
THC STRONG EVIDENCEUS potency-monitoring data shows average THC in seized cannabis rising from ~2% in the 1970s–80s to well above 12–15% in recent years, with concentrates reaching 60–90%. "Cannabis today" and "cannabis in the studies from 1985" are not the same exposure.
THC STRONG EVIDENCEEaten THC passes the liver first, where it converts to 11-hydroxy-THC — a metabolite that crosses the blood-brain barrier more efficiently and is more potent per milligram. This is pharmacology, not imagination, and why the same milligrams hit harder eaten than smoked.
THC STRONG EVIDENCETHC is highly lipophilic: after use it partitions into body fat and redistributes slowly back into blood. This storage-and-release cycle is why urine tests can stay positive for weeks after the last use — and why heavy users can show measurable blood THC days into abstinence.
THC MODERATE EVIDENCEDelta-8-THC is a naturally occurring isomer, roughly half to two-thirds as potent as delta-9. Plants make it in trace amounts, so commercial delta-8 is chemically converted from CBD. That conversion market grew in a regulatory gap, with little oversight of reaction byproducts — poison-control calls followed.
THC LIMITED EVIDENCETetrahydrocannabivarin (THCV) acts as a CB1 antagonist at low doses — the opposite move of THC — and early human studies explore it for appetite control and blood-sugar regulation. Effects flip at higher doses where it can activate CB1. Fascinating pharmacology, thin human data.
THC