THC

THC, or tetrahydrocannabinol, most commonly refers to delta-9-tetrahydrocannabinol (Δ9-THC), the principal psychoactive constituent of cannabis. It occurs naturally in Cannabis sativa and can also be produced synthetically. Other cannabinoids and isomers, such as delta-8-THC, can occur in smaller amounts and may produce similar but typically milder effects.

Pharmacology and effects: THC acts as a partial agonist at cannabinoid receptors, with high affinity for CB1 receptors in the brain and CB2 receptors in the immune system. Activation of CB1 alters neurotransmitter release, producing euphoria, altered perception, analgesia, and antiemetic effects. The onset and duration depend on the route of administration: inhalation yields rapid effects within minutes, while oral consumption is slower and longer-lasting. THC is metabolized in the liver to 11-hydroxy-THC, an active metabolite, and is eliminated through urine and feces. Repeated use can lead to tolerance and alterations in receptor signaling.

Medical use and regulation: Purified forms such as dronabinol and nabilone are approved in several countries for chemotherapy-induced nausea and vomiting and for AIDS-related anorexia. Some jurisdictions permit medical cannabis or cannabis-derived products for additional conditions, and use patterns vary widely by country and region. Ongoing research investigates potential benefits for chronic pain, multiple sclerosis, and other conditions, alongside monitoring of risks.

Safety and risks: Acute effects include impaired memory and psychomotor performance, altered judgment, and coordination difficulties. Anxiety, paranoia, and tachycardia can occur, and there is potential for dependence and withdrawal with heavy or prolonged use. Long-term use, particularly starting in adolescence, may be associated with cognitive effects in some individuals, though findings are nuanced and context-dependent.

Legal status: THC is regulated differently around the world, ranging from strict prohibition to regulated medical and recreational markets. Legal frameworks commonly address age limits, product potency, labeling, and public health safeguards.