How Long Does THC Stay In The Body?
Introduction
If you’ve recently used cannabis, you might wonder: How long does THC stay in your body? The answer isn’t simple, because it depends on several factors, including how often you use it, the amount consumed, your body composition, metabolism, and the type of test being used. In general, THC can remain detectable for hours in blood, days in saliva, weeks in urine, and up to three months in hair follicles.
For heavy users, traces can linger even longer. Understanding these timelines is essential if you’re facing a drug test, breastfeeding, or simply curious about how cannabis interacts with your system.
What Is THC and How Does It Work in the Body?
Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis. When you smoke or ingest marijuana, THC rapidly enters the bloodstream and binds to cannabinoid receptors in the brain and body, producing effects like relaxation, altered perception, impaired coordination, or in some cases anxiety and paranoia.
Once absorbed, THC is:
Stored in fatty tissues (liver, lungs, spleen, body fat).
Metabolized in the liver into compounds like 11-OH-THC (psychoactive) and THC-COOH (inactive).
Excreted through urine and feces over time.
Because THC is fat-soluble, it accumulates in the body with frequent use. This means a single puff may clear quickly, but chronic use can leave metabolites detectable for weeks.
Related: CBD vs. THC: How Do They Differ?
Detection Windows by Test Type
The length of time THC stays in your body depends largely on the type of test being used.
Blood tests usually detect marijuana for up to 12 to 36 hours after use, although in chronic heavy users, it may remain detectable for up to a week.
Saliva tests offer a short detection window as well, typically between 24 and 34 hours, though in frequent smokers THC may still be present for as long as 72 hours. Because saliva tests are easy and non-invasive, they are sometimes used for roadside screenings, but they are not reliable for long-term detection.
Urine tests are the most common form of drug testing and can detect cannabis metabolites for anywhere from 3 days to over 30 days, depending on frequency and dosage. Occasional users may test clean within a few days, while daily or heavy users may continue to test positive for several weeks after stopping.
Hair tests provide the longest detection window, with THC potentially showing up for up to 90 days. However, these tests are better at identifying consistent, heavy use and may miss single or occasional consumption.
Less commonly discussed is breastmilk testing, which has shown that THC can remain present for up to six days after use. This is important because THC can transfer to an infant and may negatively affect brain development. Taken together, these detection methods illustrate that the time THC remains in your body can range from a single day to several months depending on your usage habits, body chemistry, and the type of test administered.
Factors That Influence How Long THC Stays in Your Body
The wide range in detection times comes down to individual differences and lifestyle factors.
1. Frequency of Use
Occasional users (once or twice a month) may clear THC in a few days.
Moderate users (several times a week) may test positive for 5–15 days.
Heavy users (daily or multiple times daily) may test positive for 30+ days.
2. Body Fat Percentage (BMI)
Because THC is fat-soluble, individuals with higher body fat may retain metabolites longer.
3. Genetics and Metabolism
Enzymes like CYP2C9 and CYP3A4 affect THC breakdown. Some people metabolize it faster than others due to genetic differences.
4. Route of Consumption
Smoking/vaping delivers THC almost instantly to the bloodstream but clears faster.
Edibles take longer to metabolize and may extend detection windows.
Concentrates/dabs contain higher THC, prolonging clearance.
5. Potency and Dose
The stronger the strain (high THC percentage), the more metabolites remain in your system.
6. Other Medications or Substances
Certain drugs can speed up or slow down THC metabolism by interfering with liver enzymes.
7. Overall Health & Hydration
Hydration, kidney/liver health, and overall wellness can influence how efficiently your body clears THC.
Half-Life of THC and Why It Matters
One of the key reasons THC lingers in the body is its relatively long and variable half-life. The half-life of a substance is the amount of time it takes for its concentration in the body to decrease by half. Unlike alcohol, which leaves the body in predictable stages, THC behaves very differently because it is fat-soluble. This means it gets stored in fatty tissues and organs, slowly releasing back into the bloodstream over time before being metabolized and eliminated.
In people who use cannabis infrequently, the half-life of THC is typically about one to two days. This means that within a couple of days, much of the active THC will have left the body. However, in regular or heavy users, studies have found that the half-life can stretch to five to thirteen days, and in some cases, even longer. This occurs because THC accumulates in fat cells faster than the body can eliminate it, creating a kind of “reservoir effect” where the compound is slowly released over weeks.
It’s also important to note that THC doesn’t have just one metabolite, it breaks down into dozens of by-products, including 11-hydroxy-THC (which is still psychoactive) and THC-COOH (inactive, but the main target of most drug tests). These metabolites have their own half-lives, with some lasting just a few hours and others persisting for up to 10–13 days. Because drug tests look for metabolites rather than THC itself, the detection window often extends far beyond the period of actual intoxication.
Ultimately, it takes about three to five half-lives for a substance to be fully eliminated from the body. For THC, this means clearance could range from a few days in light users to several weeks or even two months in daily users. This variability explains why two people can smoke the same amount of cannabis yet test positive for very different lengths of time. Genetics, body fat, liver function, and frequency of use all play a role.
Understanding the half-life of THC is important for anyone concerned about drug testing, workplace screening, or health effects during pregnancy and breastfeeding. It also highlights a crucial point: just because someone tests positive for THC does not mean they are currently impaired. Instead, it often reflects past use, which is why the conversation around cannabis, drug testing, and impairment continues to evolve in both scientific and legal communities.
Can You Speed Up THC Elimination?
Many people look for shortcuts, especially before a drug test. However, the science is clear: there’s no proven quick fix.
Common Myths & Why They Don’t Work:
Detox kits & teas: Marketed as solutions, but studies show little to no effectiveness. Some may even be dangerous, causing liver dysfunction or psychiatric symptoms.
Drinking excessive water: May dilute urine temporarily, but labs check for dilution. Overhydration can also be life-threatening.
Exercise right before a test: Can actually backfire by releasing stored THC metabolites from fat into the bloodstream.
Household chemicals (bleach, vinegar, etc.): Dangerous and easily detected by validity testing.
The only reliable method is stopping cannabis use long enough for the body to naturally eliminate THC.
Related: Top 10 Myths About Marijuana Debunked
Health & Lifestyle Implications
Workplace Drug Testing
Even in states where cannabis is legal, many employers maintain drug-free policies. Standard pre-employment and random screenings often use urine or hair tests. A failed test can result in losing or being denied a job.
Driving & Legal Risks
Blood and saliva tests are sometimes used in traffic stops or after accidents. Unlike alcohol, there isn’t a standardized THC threshold for impairment, which complicates legal outcomes.
Pregnancy & Breastfeeding
THC can cross the placenta and remain in breastmilk for days. Studies suggest risks to infant development, including hyperactivity, poor cognition, and long-term behavioral impacts.
Cannabis Use Disorder
Contrary to the belief that marijuana isn’t addictive, about 30% of users develop some degree of cannabis use disorder. Those who start before age 18 are 4–7 times more likely to develop dependence later in life. Signs include inability to cut down, cravings, and continued use despite harm.
Related: How to Pass Drug Test for a New Job if You Are a Cannabis User
Short-Term and Long-Term Effects of THC
Short-Term (Hours to a Day)
Relaxation or euphoria
Altered perception of time and senses
Impaired coordination and memory
Dry mouth, red eyes, increased appetite
In some, anxiety or paranoia
Long-Term (Chronic Use)
Cognitive impairment (memory, focus, problem-solving)
Cardiovascular strain (elevated heart rate, increased risk of heart disease)
Respiratory issues from smoking (chronic bronchitis, infections)
Increased risk of mood disorders (anxiety, depression)
Possible heightened psychosis risk in genetically predisposed individuals
Final Takeaway
So, how long does THC stay in the body? The honest answer is: anywhere from a few hours to several months, depending on your usage patterns, body type, and the drug test administered. Blood and saliva tests cover very recent use, while urine tests are the most common and can detect THC weeks after the last session. Hair tests provide the longest window, up to 90 days.
The only guaranteed way to pass a drug test is abstinence, and for those struggling with chronic use or dependence, professional support is available. Whether you’re concerned about employment, health, or personal recovery, understanding how THC interacts with the body is the first step to making informed choices.
If you live in Virginia and are considering medical cannabis as a treatment option, CannabisMD TeleMed is the most trusted choice. Our board-certified physicians provide convenient online evaluations, personalized treatment plans, and compassionate care to help you access Virginia’s medical marijuana program legally and safely. With thousands of satisfied patients and multiple locations across the state, CannabisMD TeleMed makes the process simple and stress-free. Book an appointment today to take the next step toward better health and peace of mind.
FAQs
-
THC can stay in the body anywhere from a single day to more than a month, depending on how often you use it, the potency, and your body’s metabolism. Occasional users may clear THC within a few days, while heavy daily users can test positive for several weeks or even up to 90 days with hair testing.
-
Yes, even a single use of cannabis can show up on a drug test. Urine tests may detect THC for up to three days after one-time use, and hair tests can sometimes capture a record of use months later.
-
There is no proven method to eliminate THC from your body faster. Hydration, exercise, or detox kits may have minor effects, but the only reliable way to clear THC is to give your body time to naturally metabolize and excrete it.
-
If you smoke once a week, you may still test positive, especially in urine tests that can detect moderate use for up to a week or more. Your risk of failing increases with stronger cannabis products or if you have a slower metabolism.
-
It is possible for some light or first-time users to clear THC in about three days, but this isn’t guaranteed. Frequent or heavy users will almost always need more time, often several weeks, to test clean.
