How long does cannabis stay in your system?

Published Jan 29, 2019 02:58 p.m. ET

The answer to that question depends on several deciding factors. Cannabis metabolites (the specific component these tests look for) are fat-soluble. What that means is that they will bind to the fat molecules in your body. Because of this, it can take a fair amount of time before they are no longer detectable. Research shows the averages for the length of time required for a person to no longer test positive for cannabis can vary greatly. From 3 days to 90+ days depending on the test.

Test specific guidelines


 This one is the most commonly used. The following guidelines show the average time that must pass for cannabis to no longer show up in a urine test.

Occasional users are referred to as those who partake less than three times a week. In this group, tests will generally show positive for three days after use.

Regular users are those who partake an average of four times a week. For this group, cannabis remains detectable for 5-7 days after last use.

Daily users also referred to as chronic users, are those who consume cannabis daily. For this group, traces can generally be found for 10-15 days after last use.

Heavy users are those who use multiple times a day. For them, cannabis can show in a urine test for more than 30 days after marijuana was last consumed.


Cannabis is generally only detectable by this method for a short one or two days after last use for regular users. However, there have been cases where it has shown as long as 25 days after. Mainly in heavy daily users.

Cannabis is detectable within seconds of entering your bloodstream. This happens immediately during your first puff and not long after eating for those consuming edibles. So don't think you can smoke or eat edibles and then take a blood test right away.


Blood testing is generally much more precise and typically only used in a lab while searching for evidence of recent consumption.


Cannabis can enter saliva through consumption and also through exposure. (Sitting in a room with someone else smoking.) However, the metabolites are only detectable when weed has been smoked, vaped or eaten.

For occasional users, cannabis can show up on a saliva test for 1-3 days after consumption.

For daily users, cannabis can show for anywhere from 1-29 days after last consumption.


Hair testing can show drug consumption for up to 90 days. After use, marijuana gets into the hair follicles through very small blood vessels.

Since hair grows approximately ½ inch a month, a 1 ½ inch hair is taken as close to the scalp as possible and can provide a view into a person's marijuana use for approx three months.

There are no guarantees when it comes to these tests. These guidelines are just that. Guidelines. It is entirely possible (though less likely) that you could test positive for cannabis even if staying strictly within these guidelines. There are many “system cleansing” kits boast high success rates. Claiming either to mask the molecules that make a test show positive, or to flush out your system entirely. Most are incredibly ineffective. The best way to cleanse your system is to make sure to drink a good amount of water, maintain a healthy diet and get out and exercise.



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