Whether you're expecting a drug test from your employer or planning on giving one to your teen, you might be wondering just how long marijuana stays in your system. There is no one answer to this question, as the drug remains in the body for different amounts of time, depending on a variety of factors. Learn what makes a difference when it comes to detectable levels of THC after marijuana use.
Frequency of use
The chemical THC, which causes the psychoactive effects of marijuana, is also the ingredient looked for in drug tests. THC is stored in the fat cells of the body and excreted through blood, urine and other bodily fluids.
Because of marijuana's ability to accumulate in the body's tissues, a heavy user has the drug stay in their system for much longer than an occasional user. While an occasional user might be all clear for a urine drug test seven to 10 days after their last use, a chronic smoker might take months to get all the THC out of his or her system.
In cases of extremely heavy use, a marijuana smoker might even experience the psychoactive effects of THC when they haven't smoked in days, because of the sheer amount of the chemical stored in the body.
Method of use
A second factor that affects how long marijuana stays in your system is the method of use. Marijuana is ingested through two main methods: either inhaling the substance or eating it. THC is absorbed through either the lungs or the digestive system, depending on how it is used.
In general, when marijuana is smoked or vaporized, it does not stay in the body for as long as when it is eaten. After smoking marijuana, THC reaches peak blood levels within two to 10 minutes, and the "high" lasts for around three to four hours. Those who eat the substance can expect it to take two to three hours to reach peak blood levels of THC, and another four to 10 hours for the high to subside, depending on what else you have eaten that day.
THC content of the plant
Like other substances, the length of time marijuana stays in your system also depends on how much of the substance you consume. Marijuana plants naturally differ in THC content and quality, so the type that is consumed can have a big effect on the length of a user's high, as well as how long it can be detected in the body. Very strong marijuana will create a longer, more powerful high and take longer to exit the system, and vice versa.
If you would like more specific answers about how long marijuana stays in your system, ask your doctor or another medical professional. Also, keep in mind that different types of drug tests, like blood, saliva and urine, can detect the substance for different amounts of time after the last time it was ingested. Be sure to consult the maker of an individual test to find out the specific detection period for that test.