How long do you need to wait before you are clear to take a drug test?
How long does Marijuana stay in your system for?
It is impossible for anyone to accurately state the time it would take for somebody to test clean. This is because there are so many different variables (see below) that impact on the rate that marijuana is both metabolized and excreted.
We can give an estimate of the time, but the most reliable way is to test yourself twice weekly until your first, morning urine sample tests clean. However, even this is not 100% foolproof because home drug detection kits have a higher upper limit of detection (usually 50 ng/mL) compared to some other medical testing kits. This means you may test negative, but a laboratory test may still show marijuana in your system.
Note that charts, graphs, or computer programs that claim to be able to predict how long it will take you to test drug-free, are essentially useless at doing this, even though they may say otherwise.
What is delta-9 THC?
The marijuana plant (Cannabis sativa) contains over 421 chemicals including 61 different cannabinoids, of which delta 9-tetrahydrocannabinol (delta-9 THC) is considered the most psychoactive. Delta-9 THC has a thick, sticky consistency (somewhere between a solid and a liquid) and is easily vaporized. It readily dissolves into lipids and fats, and once in the body gets deposited in fat (adipose) tissue, and in the liver, lungs, and spleen.
Delta-9 THC undergoes metabolism in the liver to another psychoactive compound, 11-OH-THC, and then further metabolism to the inactive THCCOOH. CYP2C9 and CYP3A4 are major enzymes involved in this metabolism and both enzymes show genetic variation – this means that some people will metabolize THC faster than normal, whereas others will metabolize it slower than normal.
What variables impact on the time Marijuana stays in your system for?
Individual variables that play a role in how long marijuana stays in your system for and detection times include:
- Body fat: People with more body fat will retain THC for longer. Skinny users have few places to store THC
- Fluid intake at the time of the test
- Genetics: Fast metabolizers will excrete THC rapidly
- How frequently you exercise
- Method and frequency of usage: Infrequent users clear THC faster than chronic users
- Type of detection test used (blood, hair, saliva, or urine)
- Your general health: Many medical conditions impact on how your body retains, stores, and metabolizes marijuana
- Other drugs taken: Many drugs interact with CYP2C9 and CYP3A4 enzymes.
In addition, the potency of the marijuana and your tolerance to it can also have an impact.
Table 1: An estimate of marijuana detection time after last usage
|Usage||Estimate of marijuana detection time|
|* Occasionally, some chronic users with a high tolerance may eliminate THC as fast as a one-time user.|
|One time only||4-8 days|
|2-4 times per week||23-35 days|
|5-6 times per week||33-48 days|
|Daily usage||49-70 days after last use*|
|2-4 times per month||11-18 days|
What are the different ways Marijuana can be tested for?
Firstly, it is important to understand the difference between qualitative and quantitative testing.
Qualitative testing tells you if a substance is there or not. It does not tell you how much of the substance is there. There will be a cut off point for detection. For example, the Alere DDs 2 Mobile test system used roadside by law enforcement agencies has a cut off level for Delta-9-THC in saliva of 25 ng/ml. Research has shown that this testing system is 97.5% accurate at this cut off (this means that more than 97 people will accurately test positive out of 100 people who have used marijuana in the past 24 hours).
Quantitative testing measures the actual quantity of a substance. This type of testing is more expensive and time-consuming than qualitative tests and is normally reserved for people who have tested positive in a qualitative test. It needs to be done in a laboratory and is used when a more defined value is needed, say, for prosecution. Quantitative testing can detect minute quantities of a substance, far below the cut off point in a qualitative test. A series of quantitative tests can determine if drug usage is ongoing or has stopped.
The most common ways marijuana can be tested for is in urine, saliva, blood, or hair. Most testing practices look for the presence of THCCOOH which has a much longer half-life (the time it takes for 50% of the substance to be excreted) than delta-9 THC. The half-life of THCCOOH is 20-57 hours in occasional users compared to 3-13 days in regular users.
Table 2: Estimated periods of detection of the marijuana metabolite THCCOOH
|Assay||Detection period (estimated)|
A false-negative is when the test result is negative for a substance, but the person has been using the substance. A false-positive is when the test result is positive for a substance, but the person hasn’t been using the substance.
Can second-hand marijuana smoke make you fail a drug test?
For kits that detect at the 50 ng/ml level the circumstances would have to be extreme, for example, if you were in a closed car full of marijuana smokers for a couple of hours and you were drug tested the next day. If you are a non-smoker in a ventilated area where other people are smoking marijuana you are generally safe.
- Krotulski AJ, Mohr ALA, Friscia M, Logan BK. Field Detection of Drugs of Abuse in Oral Fluid Using the Alere™ DDS®2 Mobile Test System with Confirmation by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). J Anal Toxicol. 2017 Dec 28. doi: 10.1093/jat/bkx105.
- Levy S, Siqueira L. Testing for Drugs of Abuse in Children and Adolescents. Clinical Report. Pediatrics 2014;133(6) http://pediatrics.aappublications.org/content/133/6/e1798.long
- Sharma P, Murthy P, Bharath MMS. Chemistry, Metabolism, and Toxicology of Cannabis: Clinical Implications. Iranian Journal of Psychiatry. 2012;7(4):149-156.
- Windows of detection. Alere Toxicology. 2018 https://www.aleretoxicology.co.uk/en/home/support/testing-explained/windows-of-detection.html
- Verstraete AG. Detection times of drugs of abuse in blood, urine, and oral fluid. Ther Drug Monit. 2004 Apr;26(2):200-5.
As a rough guide: if you smoke the occasional joint, weed will stay in your system for up to 10 days. If you smoke regularly, up to 45 days and if you smoke constantly, 90 days.
As for being detectable in a drug test, well this depends on the type of drug test. A Urine test will detect up to a month prior, but a blood test will show positive if you've smoked any weed in the last 6 months.
Also important to note that marijuana/thc residue is stored in the fat cells, so if you're skinny or have a high metabolism, the time it takes to leave your system may be reduced.
This is a difficult question to answer. Detection of marijuana or its metbolites in the urine depends on many factors such as drug potency, tolerance, patients condition, fluid intake at time of test, method and frequency of marijuana use, patients metabolism etc etc.
It is impossible for anyone to estimate the time it would take for someone to test clean. The best thing you can do is if you know you have a drug test coming up stop immediately. You could also test yourself twice weekly and when you have your first clean reading you would have a resonable idea of how long it takes for you to clear marijuana.
As a general estimation if you smoke rarely your urine may be clear of metabolites in less than 1 week and if you are a more frequent user it could be anything beween 3 and 50 days.
It is worth noting that marijuana metabolites are stored in fat tissue so those users who are overweight will probably take longer to clear the drug.
The first answer is correct. It really depends on how much pot you smoke or smoked and your metabolism. If it is a urine test, you can drink alot of water the day before and day of test to flush it out. I have done it plenty of times to know that it works. I am not condoning it but its some help. Also if it is a hair test its there for good.
I agree with the first two posts. i do not use marijuana on a regular basis anymore but at a time when i did i tested negative after 7 days clean. I am skinny and have a high metabolism. It would also seem logical-I say this because i cannot be 100% sure on this, that if you consume fatty foods or foods with a high level of carbohydrates while "high" and remain innactive it will stay in your system longer. Marijuana is one of those drugs you can never be sure about in these regards though and there is no rule of thumb when judging an amount of time to stay clean to pass a drug test.
hi there I´m 41 years old i have been clean for 8 years now, and was addicted to almost every durg out there ... started with the occasional joint, the problem is not how long it stays in your system, the problem is that in time you are killing brain cells( becoming a walking zombie), and the worse is the mental dependency ( first twice a week ... then believe me everyday and more than one joint... tolerance) and the worst is that it opens the doors for more hardcore drugs. I wasted 20 years of my life 2 wives my children ... MY DIGNITY.
My advice to you as you seem young is to stop now, while you have time and stop worrying about how long TCH (is what gets you high) stays in your system.
if you are not currently using marijuana and you use it one time ONLY ( one joint or one pipe load) it will take 3 -5 days for your system to be cleansed of the medication. if you are not currently using marijuana and use it several times over the course of 2 -3 days it will take approx 2 -3 weeks after for your system to be cleansed of the medication. if you are a regular daily marijuana user it will take 1 - 3 MONTHS after stopping the medication for your body to be cleansed of it. if you are overweight it will take longer than if you are a normal weight for your body to cleanse itself of the medication as THC ( the active ingredient in marijuana ) is stored in the bodys fat cells. also the heavier your use of course the longer it will take for your body to cleanse but regular daily users should expect a minimum of 30 days for your body to cleanse.
Search for questions
Still looking for answers? Try searching for what you seek or ask your own question.
Posted 6 Sep 2009 • 1 answer
Posted 8 Nov 2009 • 1 answer
Posted 15 Mar 2010 • 1 answer
Posted 2 Nov 2010 • 1 answer
Posted 26 Apr 2011 • 5 answers