How Long Does THC Stay in the System? Duration and Influencing Factors

THC cannabinoids, delta-9 THC cannabinoids, in particular, are responsible for the high behind marijuana. Because cannabis produces 100s of cannabinoids, with all besides delta-9 THC, either being unable to or they appear in such low amounts they can’t, drug tests are designed to look for delta-9 THC and their metabolites (THC-COOH). 

Despite the effects of a cannabis item wearing off within a couple to several hours, THC metabolites don’t disappear then. No, no, no, they love sticking around in the body, sometimes for weeks. How long THC stays in the system is influenced by several factors, and if you’re not careful, you can test positive for marijuana use over a month after stopping thanks to those metabolites. 

Detection Windows for THC

The ability for a drug test to detect THC is greatly influenced by the type of test it is. 

Urine Test

• Occasional User: Up to 3 days
• Chronic User: Up to 30 days or more

The urine test is without a doubt the most common due to its affordability, ease of administration, and ability to detect drugs up to 30 days — sometimes even longer. This test relies on detecting THC-COOH metabolites. Frequent high doses of CBD products and non-delta-9 THC items like THCV and delta-8 THC can all theoretically cause you to fail a urine drug test. 

Blood Test

• Occasional User: Up to 24 hours
• Chronic User: Up to 7 days

Blood tests are great for accurately detecting recent consumption of cannabis use. However, like other tests, the blood test can detect marijuana use long after the person is no longer feeling its effects. Administration of blood drug tests are typically performed by law enforcement when recent drug or alcohol use is suspected. 

Saliva Test

• Occasional User: Up to 48 hours
• Chronic User: Up to 72 hours

Saliva tests are less common than urine tests, but after researchers from the University of Texas created a saliva test in 2023 that can measure the level of THC with 94% accuracy, this may start to change. This device may offer a better alternative to blood tests for law enforcers undertaking roadside tests who need to detect whether a person is driving impaired.

Hair Test

• Occasional User: Up to 90 days
• Chronic User: Up to 90 days or longer

Hair tests are less common compared to urine, blood, and saliva tests for several reasons. While they have an amazingly long detection window, it’s pretty much too long, making it a bad test for determining just how far out someone used marijuana. An employer is much less likely to care about marijuana use 3 months out vs. a week. Then it requires more expensive and specialized equipment that requires greater knowledge to perform. 

Factors Influencing THC Detection Times

Need to pass a drug test, in particular a urine test? Then it’s time to hit the gym. There are several factors that influence how far out THC is detectable in your system. And most techniques to clear THC from your system involve a fitness program. Like THC, THC metabolites are fat-soluble, meaning the more body fat you have on you, the more material those metabolites can stick around in. 

Staying well hydrated while safely losing as much fat as possible — about a 500-calorie deficit daily for most — can significantly affect whether you pass a drug test. Overweight individuals can push that rate higher, while leaner folk will need to ensure they are getting enough protein while lifting heavy to avoid muscle loss. 

It should go without saying that you must stop all consumption of cannabinoid-based items, including full spectrum CBD products, if you want to pass a drug test. How much THC you’ve consumed and how frequently will greatly factor. Then, it’s important to remember that people metabolize cannabinoids at various rates, i.e., some will clear THC from their system faster than others. 

THC Detection in Different Testing Methods

Different drug testing methods have different detection windows, which can make one more useful vs. another. While employers may be concerned about drug use at most a month out, law enforcement may be less so and more concerned with finding out if you're high at the time of the test. However, a probation officer may prefer a hair test so they can check up to three months out if it falls under the probation period. 

All tests offer their own pros and cons, and it’s hard to say which test you may face depending on the scenario you’re in. In most cases, if you have to take a drug test, it's most likely a urine drug test. 

To Conclude

THC, specifically delta-9 THC, is responsible for the intoxicating effects of marijuana. When cannabis is consumed, THC metabolites form in the body and can be detected in drug tests long after the immediate effects wear off, sometimes for months. The duration of THC detection varies based on factors like the type of drug test and individual metabolism.

Factors like body fat, hydration, and frequency of THC consumption influence detection times. It's crucial to cease cannabinoid consumption before a drug test, consider your individual metabolism rate, and understand the test you are taking. Different tests suit different purposes, with urine tests being the most common in various scenarios, though the specific test may vary based on the situation.

See also: Articles, Cannabis, Research & Studies

Nicholas McEnzie

Cannabis Expert EditorExpertise : Cannabis and Hemp Cultivation

Over the past decade, Nicholas McEnzie has dedicated himself to educating gardeners, enterprises, and enthusiasts on thriving in the dynamic cannabis industry. Whether he's actively involved in cultivation or conducting research on cannabinoids in the laboratory, Nicholas is committed to providing thoroughly researched, accurate, and clear information to a sector that greatly benefits from it.