Addiction Drug Addiction How Long Does Marijuana Last? Weed (Cannabis) in Your Blood, Urine, Hair, & Saliva By Buddy T Buddy T Facebook Twitter Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism. Learn about our editorial process Updated on February 22, 2023 Medically reviewed Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Steven Gans, MD Medically reviewed by Steven Gans, MD Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital. Learn about our Medical Review Board Print Seth Ryan/EyeEm/Getty Images Table of Contents View All Table of Contents Effects Duration Detection Times Elimination Symptoms of Overdose Getting Help The effects of marijuana fade quickly, but the drug can last in the body for weeks and sometimes longer. The amount of time the active ingredients and breakdown products of weed remain in the system can range from a few hours to 90 days, depending on how often or how much marijuana the person has been using. For example, a single dose of weed can stay in your system for up to 13 days, depending on the type of test used. If you rarely smoke weed or only have a few puffs, it will leave your system more quickly than if you use marijuana frequently or heavily. Although a number of states in the U.S. have active medical marijuana laws and recreational use of marijuana for adults over the age of 21 is legal in 12 states, Washington, DC, the Northern Mariana Islands, and Guam, the federal government continues to classify marijuana as a Schedule I controlled substance. According to the Substance Abuse and Mental Health Services Administration (SAMHSA), roughly 1 in 10 people who use marijuana will become addicted—and these rates rise to 1 in 6 if they start using the drug prior to age 18. The FDA has not yet approved medical marijuana for any medical indication, but it is often prescribed for chronic pain, nausea, HIV, multiple sclerosis, glaucoma, and irritable bowel syndrome (IBS). How Long Does Weed Stay In Your System? Blood: Up to a few hoursUrine: From 13 (for single use) to 90 days (for heavy use)Saliva: Up to a few hoursHair: Up to 90 days What to Know About Marijuana Use How Long Does It Take to Feel the Effects? The effects of marijuana can vary from person to person. Some people may feel euphoric and relaxed while others feel anxious and paranoid. In other cases, people report feeling "dopey" and experience a loss of interest in activities or an inability to grasp concepts. The chemical in marijuana that makes you feel "high" is tetrahydrocannabinol, also called delta-9-THC or simply THC. It enters the body's bloodstream rapidly after smoking marijuana. If weed is ingested orally rather than smoked, it takes longer to be absorbed into the blood, usually from 20 minutes to an hour and a half, but this can vary based on the amount taken as well as physiological factors such as absorption and rates of metabolism and excretion can influence drug concentrations in circulation. Effects can be far-ranging depending on the strain, method of consumption, and amount and can include the following: Dry mouthSwollen eyelidsBloodshot eyesPleasurable body sensationsIncreased appetite ("the munchies")RelaxationStimulationDistorted perception (sights, sounds, time, touch)Loss of coordinationTrouble with thinking, memory, and problem-solvingIncreased heart rate The short-term effects of marijuana on memory, learning, problem-solving, and coordination last for one to two hours, with some lingering effects for up to 24 hours. It's been shown to impair your driving performance for up to three hours, according to the National Highway Safety Administration. The effects of weed are also influenced by the terpene profiles of a given strain. For instance, citrus terpene profiles tend to be more stimulating, which may be the desired effect, or may contribute to someone feeling anxious. It is important to know that not all marijuana is created equal. Unlike other prescription drugs, marijuana products aren't standardized and can vary considerably in quality, makeup, and dosage. This variance may contribute to how quickly you feel the effects and what those effects are. THC can interact with alcohol, blood thinners, and anti-anxiety medications, so it's important to discuss your marijuana use with your doctor. How Long Do Marijuana's Effects Last? The half-life of marijuana is how long it takes for half of the drug to be metabolized and eliminated from the bloodstream. THC is rapidly broken down and modified into molecules known as metabolites. At least 80 different metabolites are formed from THC and may have their own effects on the body's endocannabinoid system. These metabolites are stored in body fat and are gradually eliminated from the body through feces and urine. Some THC metabolites have an elimination half-life of 20 hours, whereas others are stored in body fat and have an elimination half-life of 10 to 13 days. It takes five to six half-lives for a substance to be almost entirely eliminated. This is why you see advice that one-time use is probably not detectable after five to eight days. Blood and Saliva Because marijuana stays in the bloodstream for only a short time, blood tests for marijuana are usually not used. The exceptions are in the case of automobile accidents and some roadside sobriety checkpoints. Blood or saliva tests can show current intoxication. However, unlike blood alcohol concentration tests, they do not indicate a level of intoxication or impairment. Hair Daily or near-daily cannabis consumption is likely, but not always, detectable by a hair test up to three months later. But, the hair test is not reliably able to detect infrequent cannabis use or determine the amount of cannabis used. Urine Urine tests for marijuana metabolites also only show recent marijuana use, not current intoxication or impairment. This is because of the time required between use and your body breaking down THC to the metabolites that are eliminated in the urine. Because many employers have a zero-tolerance for drug use, most workplaces use urine tests to detect recent use of drugs. False Positive Testing Workplace testing for marijuana might entail first screening the sample with an immunoassay test, known as the EMIT or RIA. If positive results are returned, the sample is again screened with a gas chromatograph-mass spectrometer (GCMS), which is much more accurate and so false positives are rare. No known substances would cause a marijuana urine test to return a false positive. At one time, ibuprofen (sold over-the-counter as Advil, Motrin, and Nuprin) would cause false marijuana positives. But today's tests have been adjusted to eliminate that problem. In places where marijuana is legal, roadside blood tests have been known to show some false positives in people who had been legally consuming cannabis but were not actively intoxicated at the time of the test. A 2016 report detailed a Belgian policy of testing oral fluid at the roadside that found it decreased these types of false positives. Factors That Affect Detection Time The length of time marijuana remains in your body depends on many different factors, including frequency of use, body mass, metabolism, sex, and hydration levels. Frequency of Use There is some evidence that the length of time that marijuana remains in the body is affected by how often the person uses marijuana, how much they use, and how long they have been using. People who use marijuana regularly have reported positive drug test results after 45 days since last use, and people who use more heavily have reported positive tests up to 90 days after quitting. In a 2017 study of 136 people who use cannabis subjected to hair tests, the presence of five cannabinoids, THC, THC-OH, THC-COOH, cannabinol, and cannabidiol, were present in 77% of the heavy users and 39% of the light users. Sex Women often metabolize THC at a slightly slower rate since they tend to have higher levels of body fat than male counterparts. Metabolism The faster your metabolism, which can be impacted by age, physical activity, and certain health conditions, the faster marijuana will exit your body. Body Mass Index (BMI) THC metabolites are often stored in the fat cells in your body, so the higher your body fat (or BMI), the slower you'll likely be able to metabolize and excrete marijuana. Body Mass Index (BMI) is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes. Hydration When you're dehydrated, you'll have more concentrations of THC in the body. Flooding yourself with water won't make you pass a drug test, however. Instead, it will dilute it and you'll likely need to retake the test. Smoking vs. Vaping vs. Edibles The method of use also impacts the detection time. If marijuana is smoked or vaped, the THC levels in the body will drop faster than if you ingest it. Edibles take longer to break down in the body and leave your system. How to Get Marijuana Out of Your System The only way to rid your body of marijuana is to abstain from the drug completely. However, it's important not to detox from any drug, including marijuana, on your own without the help of a medical professional. If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. For more mental health resources, see our National Helpline Database. The experience of detoxing from marijuana is highly individual and is dependent on a variety of factors—including age, gender, sex, genetics, and history of use. For instance, if you've been using marijuana for an extended period of time, you are more likely to experience severe withdrawal symptoms compared to an occasional user who may not experience any symptoms. According to research, you may begin experiencing symptoms about a week after you stop using the drug and may witness a peaking of your withdrawal symptoms during the 10-day mark. You should experience a decline in the severity of your symptoms over the following 20 days. Before you embark on this journey, it's important to seek guidance and also consider whether you'd be comfortable detoxing at home or at a treatment facility. Keep in mind that the risk of detoxing at home can include the risk of relapse without a strong support network in place. A treatment facility can provide the structure needed to sustain sobriety and the support of peers and healthcare professionals to help ease the transition. What To Expect From A Marijuana Detox Symptoms of Overdose It is very difficult to physically overdose on marijuana because the lethal dose is so much higher than the effective dose. Very few marijuana overdoses have ever been reported. If someone you know has taken too much marijuana, and that is the only thing they have taken, an overdose is highly unlikely, but that doesn't mean that marijuana is not harmful. Psychological distress is possible as is impairment of judgment, both of which can lead to hazardous behaviors that can harm yourself and someone else. Although rare, people can experience THC toxicity when using marijuana in high doses, especially in the form of edibles. Symptoms can include: Heart arrhythmiasPsychosis or paranoia (or exacerbation of pre-existing mental health conditions)SeizuresUncontrollable vomiting If you or someone you love has a family history of mental illness, it is beneficial for you to consult your doctor before using marijuana. The concept of "set and setting" is also important. Since people who have taken too much marijuana can experience sensory overload, minimizing overstimulating inputs in the environment can help them to relax. Some people are also more affected by marijuana than others. Can You Overdose on Marijuana? Getting Help You may have a prescription for medical marijuana, or you may want to partake of weed or marijuana edibles in states where it is now legal for recreational use at the state level. There is a common perception that you cannot develop a physical dependence on marijuana, but this is not the case. Psychological dependence is also a consideration. If you discontinue marijuana after regular or heavy use, you may experience symptoms of withdrawal. Signs of marijuana withdrawal include: Appetite changeCramps or nausea after eatingCravingsDigestion problemsHeadachesMood swingsSleep disruptionWeight gainWeight loss Marijuana Withdrawal Symptoms If you find that you can't handle symptoms of withdrawal without relapsing, you may be at risk for a substance use disorder. Do not be afraid to seek out professional support from a mental health professional. There are therapists who can help you understand your reasons for using. They also can help you determine how cannabis use is impacting your life, and how to develop a plan to stop using if that ends up being the best choice for you. If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. For more mental health resources, see our National Helpline Database. Cannabis Use Disorder & Problematic Marijuana Use 8 Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Huestis MA. Human cannabinoid pharmacokinetics. Chem Biodivers. 2007;4(8):1770-804. doi:10.1002/cbdv.200790152 National Institute on Drug Abuse. Marijuana. Kulig K. Interpretation of workplace tests for cannabinoids. J Med Toxicol. 2017;13(1):106-110. doi:10.1007/s13181-016-0587-z Doucette M, Frattaroli S, Vernick J. Oral fluid testing for marijuana intoxication: enhancing objectivity for roadside DUI testing. BMJ Intervention. 2016;24(1). doi:10.1136/injuryprev-2016-042264. Taylor M, Lees R, Henderson G, Lingford-Hughes A, Macleod J, Sullivan J, Hickman M. Comparison of cannabinoids in hair with self-reported cannabis consumption in heavy, light and non-cannabis users. Drug and Alcohol Review. 2017. doi:10.1111/dar.12412. Harvard Health. If cannabis becomes a problem: How to manage withdrawal. Hesse M, Thylstrup B. Time-course of the DSM-5 cannabis withdrawal symptoms in poly-substance abusers. BMC Psychiatry. 2013;13:258. doi:10.1186%2F1471-244X-13-258 Center for Disease Control. Marijuana and Public Health. Additional Reading Doucette M, Frattaroli S, Vernick J. Oral fluid testing for marijuana intoxication: Enhancing objectivity for roadside DUI testing. BMJ Intervention. 2016;24(1). doi:10.1136/injuryprev-2016-042264. Meier M. Associations between butane hash oil use and cannabis-related problems. Drug and Alcohol Dependence. 2017;179:25-31. doi:10.1016/j.drugalcdep.2017.06.015. Taylor M, Lees R, Henderson G, Lingford-Hughes A, Macleod J, Sullivan J, Hickman M. Comparison of cannabinoids in hair with self-reported cannabis consumption in heavy, light and non-cannabis users. Drug and Alcohol Review. 2017. doi:10.1111/dar.12412. U.S. Department of Health & Human Services. Learn About Marijuana Risks. SAMHSA website. Updated. Wong A, Montebello ME, Norberg MM, Rooney K, Lintzeris N, Bruno R, Booth J, et. al. Exercise increases plasma THC concentrations in regular cannabis users. Drug and Alcohol Dependence. 2013;133(2):763-7. doi:10.1016/j.drugalcdep.2013.07.031. By Buddy T Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Get Treatment for Addiction Advertiser Disclosure × The offers that appear in this table are from partnerships from which Verywell Mind receives compensation.