This guide details how long cannabis and cannabis edibles stay in blood, urine, saliva, hair and sweat. As a bonus, we’ve included an online THC detox calculator which will tell you exactly in how many days you’ll be THC-free.
Most of the tests in use today detect THC in levels above 50 ng/dL, so until you get below that level you will keep testing positive.
Body fat percentage plays a huge role in how quickly you are able to flush THC out—the more body fat you have, the longer the THC will stay in your system as that’s where it’s stored.
Only THC is detectable in tests while other cannabinoids (such as CBD) are not detectable in all common tests.
Here’s how long weed stays in your system (Chart)
This chart provides an estimate of how many days it will take to flush THC out of your system.
Precise THC detox calculator
While the chart does provide a decent basic overview, it’s not exactly precise. This is the most accurate THC detox calculator online (based on ProfOfPot‘s formula) as it takes into account two things that influence the metabolism of THC the most: Body fat percentage and urine THC metabolite levels.
Body fat (%):
Urine metabolite level (ng/mL):
Time to clear THC (days):
As you can see, to use this calculator you’ll need to know your urine metabolite levels. Metabolite levels of frequent users hover at around 200-250 ng/mL, measured one day after using cannabis.
The only way to get exact numbers is by using a home kit THC test—don’t go for the most basic one as you’ll need a “multi-level” test that shows THC levels in ng/mL. Here is a cheap multi-level test I found on Amazon.
If you don’t know what your body fat percentage is, take a look at this visual comparison for a rough estimate.
How long is cannabis detectable in the system?
This depends on the testing method and the frequency of use. Here’s a quick overview.
THC can be detected in urine from 7-70 days.
Urine testing does not look for THC, but a nonpsychoactive metabolic intermediate—THC-COOH.
After using cannabis, our liver metabolizes THC into THC-COOH which is then stored in urine.
Again, how long THC stays in urine depends on the frequency of use.
If you’ve used marijuana just once, THC will stay in your urine for about 7 days.
If you ‘ve smoked 2 to 4 times recently but didn’t use it afterward, THC will be detectable in your urine for 10 to 18 days.
If you regularly smoke 5 or 6 times a week you can expect the metabolite to remain in your urine from 30 to 48 days.
Medical marijuana users and daily recreational users need a bit more time to completely detox—about 50 to even 70 days.
THC is detectable in blood from 1 to 7 days.
THC is only detectable in blood for a short amount of time, and so this method of testing is not that popular anymore.
After smoking, THC runs through the blood and into the fat cells, where it stays for longer periods of time.
In general, if you’re not a regular smoker and you only took a few puffs, THC will be detectable in your blood for about one to two days.
If you used cannabis a few times in the past week, THC will be detectable in your blood for about 3 days afterward.
Yet, if you are a regular, everyday user you’ll need around 7 days to flush THC out completely.
THC is detectable in hair for up to 90 days.
In fact, THC is detectable from just a single hair sample taken 1.5 inches from the scalp, which makes the hair test really scary and accurate—it can detect even picograms of THC.
Note: If your first hair sample tests positive for weed, they might ask you to provide a second sample.
THC can be detected in saliva for 1-7 days
Saliva marijuana tests are usually used by the police, through devices like the Dräger 3000.
THC and its metabolites can be detected in saliva just an hour after consuming cannabis.
If you only used marijuana once, it can be detected in your saliva for the next 24 hours.
If you are an occasional user THC can be detected in your saliva for up to 72 hours.
If you are a regular heavy consumer (or a daily medical user), saliva THC test will turn positive for up to a week.
Roadside saliva tests have been very controversial recently. The problem is that you can test positive to THC without even being high, so it’s still very difficult to determine if the driver is actually impaired or not.
THC is detectable in sweat for 7-28 days.
Sweat tests are not that common and they are usually used for monitoring patients during drug rehab treatments and employment programs.
THC metabolites can be detected in sweat for about one to four weeks.
This depends on two factors: How much sweat one produces and how much they smoke.
Also take into account environmental factors, such as temperature and air humidity.
Here’s how this test works:
THC sweat patches are applied to the skin and are usually worn from 7 to 14 days. After that period, patches are taken off for testing.
The amount of produced sweat is subjective, and so the accuracy of this testing method is somewhat limited. And it’s hard to control if someone wore the patch all the time, of course.
How long do edibles stay in your system?
Consumption method is very important when it comes to cannabis testing.
For example, when you eat a cannabis brownie, it takes much longer to get “high” when compared to smoking.
When you take an edible, cannabis has to go through the entire digestion process. Afterward, cannabinoids get processed by the liver and that’s when they enter the blood.
That’s why edibles stay in the system for 7 to 30 days.
Just 5 days after taking an edible, 80 to 90% of THC is flushed out but the remaining 10% can stay there for up to 4 weeks.
How to flush THC out quickly and detox from cannabis?
The best way to flush THC out of your system and pass the test is pretty simple—total abstinence for a set period of time.
If you know you’re going to be tested for THC, I suggest you reverse engineer the chart above and stay cannabis-free for that time period.
If it’s already too late and you don’t have the time, there are a few things you can do to speed up the detox process.
These tips could help, but there are no guarantees they will work.
Take note that research showed that people with a fast metabolism, lower body fat percentage and lower BMI can flush THC out faster than people with standard BMI.
But, here is what you can do.
1) Drink plenty of water
Staying hydrated is essential for your health in general. So if you want to flush marijuana out your system, start drinking a lot of water a few days before the test.
Keep in mind that drinking a lot of water can make your urine clear, so this could look suspicious as well.
2) Eat the right foods
As THC is stored in fat, you’ll need to avoid fatty and greasy foods as well as things rich in sugar and sodium. That means no junk food and red meat.
You’ll need a lot of food rich in fiber and antioxidants so stick to fruits, vegetables and whole grains to detox faster.
Also, vitamin C should be your new best friend. Lemonades and citrus juices are full of electrolytes which are great detoxing agents. Tea will also help you flush THC out, so drink a few cups of green, black or white tea a couple of days before your test.
Vitamin B3 is great when you’re looking to cleanse your system from just about anything. Avocados and potatoes are one of the biggest natural sources of vitamin B3 (also known as niacin).
3) Exercise and sweat
Cardio is the best way to burn fat, which is also where THC metabolites live. By exercising, we sweat more, excrete fluids and we eventually speed up the THC detox.
A workout that mixes cardio and strength would be the best to flush marijuana out, starting a few weeks prior to testing.
But, there is one tricky thing when it comes to exercising. Don’t do it on the day of testing. In fact, try to avoid all exercise a couple of days before the big day.
Even though exercise burns fat, that process also releases more THC metabolites into your blood, which could be a bad choice for the testing day.
If you’re really worried about the test, a sauna can also do wonders.
4) Get a lot of sleep
When we sleep, our whole body recovers for the following day. It’s our own, natural detox mechanism.
So, a few days (or weeks) before taking the test, try to get as much sleep as possible. Give yourself a few nights off and try to go to bed earlier than usual.