this question doesn't have a straightforward answer unfortunately. the active ingredient in marijuana is called delta-9-tetrahydrocannabinol or "thc" for short. when a person smokes marijuana the thc is rapidly absorbed by the body which causes the person to feel "high. " this effect is short-lived lasting maybe three or four hours. however an inactive form of thc (called delta thc-acid) deposits itself in the fatty tissue. this is called the "metabolite" of thc. many marijuana tests don't look for active thc in the blood stream or urine. instead they look for this thc metabolite. despite a common belief that it takes longer for heavy pot users to "test clean" than someone who smoked marijuana just one time there isn't much scientific evidence to support that idea. every individual's body is unique. some people's bodies may clear the thc metabolite more rapidly than others. detecting thc depends on the type of test used also. some very sensitive tests can measure delta thc-acid levels up to 25 days after the person stopped using marijuana. while it would be nice to have a solid answer to the question of how long thc stays in your system after smoking marijuana it's just not possible to say with certainty.
how long does thc stay in your system?