How long does cannabis stay in the body after smoking?

It depends on how often and how much cannabis a person smokes, as well as how it's taken (either smoked or ingested (eaten)). It can even vary in each person from day to day.

THC (the active chemical in marijuana) is stored in the fat cells, and takes longer than any other common drug to fully clear the body.

Research shows that regular heavy cannabis users get rid of the drug from the body differently than light occasional users do. For example:

  • people who use cannabis less frequently seem to get rid of the drug quicker
  • people who use lots of cannabis regularly store the drug as body fat. It is then released slowly over a longer period

In general, the less cannabis that’s smoked, and the less often it’s smoked, the quicker it leaves the body.

One-off or occasional users are more likely to get rid of all cannabis from their system within a few days.

For regular heavy smokers, it takes an average of two weeks to one month for it to leave their system, although it can be longer. Long-term users may still have cannabis in their body two to three months after they last smoked it.

Long-term use can make you depressed and less motivated.

Further information:

Page last reviewed: 29/11/2011

Next review due: 29/11/2013