Myth: Marijuana's Active Ingredient, THC, Gets Trapped in Body Fat

Because THC is released from fat cells slowly, psychoactive effects may last for days or weeks following use. THC's long persistence in the body damages organs that are high in fat content, the brain in particular.

Fact: Many active drugs enter the body's fat cells. What is different (but not unique) about THC is that it exits fat cells slowly. As a result, traces of marijuana can be found in the body for days or weeks following ingestion. However, within a few hours of smoking marijuana, the amount of THC in the brain falls below the concentration required for detectable psychoactivity. The fat cells in which THC lingers are not harmed by the drug's presence, nor is the brain or other organs. The most important consequence of marijuana's slow excretion is that it can be detected in blood, urine, and tissue long after it is used, and long after its psychoactivity has ended.

• Committees of Correspondence. Drug Abuse Newsletter 16 (March 1984).

• Mann, Peggy. Marijuana Alert. New York: McGraw-Hill Book Company. 1985. 184.

• Nahas, Gabriel. "When Friends of Patients Ask About Marihuana." Journal of the American Medical Association 233 (1979): 79.

• DuPont, Robert. Getting Tough on Gateway Drugs. Washington, DC: American Psychiatric Press, 1984. 68.