How Long Does THC Last In Your System And How To Reduce It

Cannabis legislation is still evolving. Some states allow medical cannabis and others have adult-use legislation.


Cannabis legislation is still evolving. Some states allow medical cannabis and others have adult-use legislation. Wherever you are, look up your local legislation to help you navigate marijuana use.

Sometimes people are concerned about how long cannabis will last in their systems. While marijuana is natural, we classify it as a drug. Maybe your career prohibits marijuana use. Whatever your reason, it’s good to know how long any substance will last in your system.

So, what about cannabis? How long will THC stay in your system? Are 21 days enough to pass a drug test? The short answer is that it depends. We are all different and metabolize weed at different rates. This can depend on your individual chemistry and tolerance. The important thing to understand if you’re concerned about THC in your system is how it’s tested for and what you can do about it. 

Testing For THC

Urine Tests

One of the most popular methods for drug tests is a urine test. If you’re trying to pass a urine test, you’ll need to think about your general habits. Do you have a tolerance for cannabis? Or are you someone who smokes once or twice a month? Technically, marijuana is detectable in urine for over 30 days. But, if you’re an occasional smoker, your urine will probably be passable after about a week. Spend some time thinking about your usage. If you’re smoking often, give yourself 30 days at least to prepare for the urine test.

Blood Test

Hopefully, you won’t ever encounter a blood test to test for marijuana use. These tests are usually reserved for urgent scenarios. Law enforcement may for example order blood tests to test for THC in impaired drivers. Or it may be necessary based on your occupation.

Blood tests cannot detect marijuana use for as long as a window as urine tests can. This is because THC is metabolized through fat tissue rather than through the bloodstream. So, for a blood test to pick up on marijuana, it needs to be performed between 3 to 12 hours for CBD-dominant strains and 6 to 27 hours for THC-dominant strains. So, depending on what you’ve consumed, your positive testing window will vary. 

Saliva Test

Testing for marijuana use using saliva tests is also rare. Like blood tests, you have a short window of detection. For occasional smokers, marijuana will only be detected in saliva for up to 24 hours. If you smoke more frequently however, your marijuana use will likely be detectable for over 30 hours. 

Hair Test

Hair tests are not a common method to detect cannabis use. This is probably a good thing because these tests can’t distinguish between first and second-hand consumption. Even if you don’t smoke yourself, being exposed to marijuana smoke may cause you to fail a hair test.

Hair follicle samples of 1.5 inches are taken to perform the test. After exposure or consumption of cannabis, you will test positive for approximately 90 days. Analyzing hair follicles is better as a qualitative measure since its impossible to distinguish between exposure and consumption.

The Science Behind THC Tests

Hold on, we’re about to get technical. THC is what gives marijuana its potency. It’s the ingredient that gets you high and provides psychoactive effects. Anyone using recreational cannabis has been exposed to THC. Even CBD products designed to reduce pain or nausea will have small amounts of THC.

Scientists think of THC differently. Its technical name is tetrahydrocannabinol but it’s often also called THC Acid, THC carboxy or 11-COOH-THC. THC Acid or THC carboxy is the naturally present forms of THC. Once we decarb (heat) cannabis, we get the psychoactive version of THC. Drug tests don’t just test for THC alone. Labs are interested in finding THC metabolites in the body. This is also called THC-COOH and is found after cannabis is consumed and processed by your body. This metabolite remains in the human system longer than THC itself and is part of the reason why it’s tested for.

Getting Rid of THC Metabolite

If you’re being tested for marijuana use, you probably want to test negative. The first thing you can do to influence your results is to stop smoking. Depending on the window you’re working with, this can be critical. The same goes for any other methods of cannabis consumption. Remember, the more frequent you use, the higher your chances of detection. You’ll feel more prepared for your test and be able to let go of some stress. But, if you’re really in a pinch there are a few tips and tricks you can try.

Body Fat & Metabolic Processing

THC binds to fat cells. Initially, you might be tempted to try to lose fat by exercising or dieting before a drug test. But, this would be ill-advised. The thing is, if you do exercise and lose fat, the THC metabolites will be released back into your bloodstream. So, the more you try to exercise the THC away, the more likely you’ll be to fail your test. So, if you have a drug test coming soon you’re best to stop hitting the gym. The only thing you can physically do is to eat healthily and hope your metabolism is fast enough to pass THC through your system before your test date.

Cranberry Juice Or Miracle Cocktail?

If drinking cranberry juice sounds like a crazy method to you, you’d be right! But, some people swear that it works. Cranberry juice has long been touted as a natural diuretic and solution to a variety of medical conditions. Some people think this natural remedy is also helpful when trying to rid your body of THC metabolites. While this solution definitely sounds tempting, there is no real evidence that this works. In theory, because THC is bound to fat cells, peeing more will not help you pass a drug test. So, while there are no guarantees that drinking cranberry juice will help you get rid of lingering THC, it isn’t the worst remedy in the world to try!

Will My Results Depend On What I Smoke?

The short answer is yes. But that doesn’t mean you’ll pass a drug test if you only smoke a certain strain of marijuana. 

Strains with high levels of THC stay in your system longer than lower potency varieties. Look for marijuana that is CBD dominant if you’re concerned about the possibility of testing. The less THC you consume, the fewer metabolites will be in your system. Your best bet when preparing for a drug test however is to stop consuming cannabis.

If you’re not smoking weed at all, the rules change. Edible cannabis products are metabolized differently. Ingesting marijuana causes your body to hold onto metabolites longer. So, between smoking and consuming cannabis, it’s safer to smoke a low THC strain if you have an upcoming test.

The Takeaways

You may have come across this article because you have a scheduled drug test coming up. Or maybe you’re applying for a new job and think it’s inevitable! Whatever your reason, you’ve probably come across a lot of different advice – like that you only need to stop smoking for 21 days to pass a drug test. Remember, if a solution to rid your body of THC sounds too good to be true – it is. You can drink all the cranberry juice in the world, but nothing will guarantee that you pass the test like abstaining will.