How Long Does THC Stay in Your System?
Last Updated Dec 2, 2021
Generally, THC can stay in a person’s system for anywhere from 1 to 30 days. How long THC stays in the system depends on a variety of factors which include frequency of use as well as certain physiological factors.
Tetrahydrocannabinol (THC) is an active compound that produces psychoactive effects in users. After use, THC is detectable via a variety of testing methods, such as urine, blood, hair, and saliva tests.
How Is THC Detected?
THC metabolites remain in the body’s system longer than actual THC does after marijuana use. As a result, many of the most common THC or marijuana testing methods detect the presence of THC-COOH as well as other metabolites.
Urine tests are the most common, but THC’s active compound can also be detected through blood or saliva.
THC & the Body
When ingesting marijuana, THC travels from the lungs or mouth to the bloodstream, ultimately making its way to the brain and connecting with specific cells (receptors). THC also gets stored in organs (the liver, bladder, and kidneys, for instance) as well as fatty tissues.
The liver breaks down THC and its over 100 metabolites. Essentially, any form of drug test looks for these metabolites, which end up staying in the body longer than THC.
Ultimately, TCH and its associated metabolites end up being flushed out of the body through urination and defecation.
Timeline of THC Processing
How long THC and THC metabolites stay in the system depends on a variety of factors. Frequency of use is a major factor. For instance, a first-time marijuana user might metabolize THC metabolites fully in around 3 days.
Whether someone uses THC for medical reasons or recreational purposes, someone who uses cannabis every day might end up having detectable amounts of THC metabolites for 30 days or even longer.
Drinking lots of water, eating healthy foods, and exercising do not speed up the processing timeline, contrary to popular beliefs.
The higher the amount of THC metabolites in the body, the longer the timeframe for excretion.
Urine, Blood, Saliva & Hair Tests
The primary methods for marijuana detection in the body include urine (most common), saliva, blood, and hair tests.
Saliva tests have the earliest detection window and in select cases can actually detect same-day marijuana use. Those who smoke frequently can often have detectable amounts of THC and THC metabolites for up to 72 hours.
Saliva testing is most often used in states where marijuana is illegal during roadside sobriety tests.
THC and its metabolites do not stay in the bloodstream for long, so blood testing is rarely used. Exceptions include vehicular accidents as well as roadside sobriety tests.
Both blood and saliva tests can convey current intoxication, but they cannot detect levels of intoxication as blood-alcohol concentration tests have the ability to do.
Hair tests can detect THC for around 90 days. This method of testing is more expensive than other methods, so it is seldomly used for THC.
Hair testing can detect frequent marijuana use, but it is less reliable detecting infrequent use. It cannot detect the specific level of use.
Urine testing is by far the most common method of testing for marijuana and THC. Urine tests can convey recent marijuana use but not current levels of intoxication.
Most employers utilize urine testing to screen for recent drug use.
Factors That Affect How Long THC Stays in Your System
The two strongest determining factors when it comes to how long THC and THC metabolites stay in the body’s system are frequency of use and body mass index (BMI).
Method of use also affects how long THC stays in the system. Vaping and smoking marijuana has a shorter detection window than consuming edibles, for instance.
Use of Marijuana: Effect on Brain Health: A Scientific Statement From the American Heart Association. (February 2022). American Heart Association.
Effects of Δ9-Tetrahydrocannibinol (THC) on Obesity at Different Stages of Life: A Literature Review. (March 2022). International Journal of Environmental Research and Public Health
Cannabis and Driving. (September 2021). Frontiers in Psychiatry.
Interpretation of Workplace Tests for Cannabinoids. (March 2017). Journal of Medical Toxicology.
Objective Testing: Urine and Other Drug Tests. (March 2016). Child and Adolescent Psychiatric Clinics of North America.
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