This is pretty interesting, and it's a study from Colombia University....Just hope to God that they don't do a "hair folicle' test on you.......read on: This is from Wikipedia..........
Marijuana itself does not "stay" in your system, but the main chemical in marijuana, THC, does. It fact, it may stay in your system forever because it is stored in fatty tissues of various organs.
Despite being stored in body fat, THC is only detectable for a certain amount of time. Many drug tests, including urine tests, look for 9-carboxy-THC which is the by-product of your body metabolizing the THC in your fat.
According to Columbia University's Health Services site, THC and its metabolizing by-product can be detected within the following time frames.
Marijuana Detection Times
Frequent users* blood drug test
THC: 4-8 hours after smoking
THC by-product: 2 or more weeks after smoking
Frequent users urine drug test
THC by-product: 2 weeks to a month after smoking (3 months for extremely heavy users)
Infrequent users blood drug test
THC: 3-4 hours after smoking
THC by-product: 2-3 days after smoking
Infrequent users urine drug test
THC by-product: up to 10 days after smoking
* In this case, Columbia University defines a frequent user as someone who smokes several times per week.
Additional input from other WikiAnswers contributors:
* I attended a court ruled drug class and learned that marijuana has a halflife in your system. How long it takes to leave your system depends on how much you smoke. But the time maxes out at around 45 days. One smoking session for someone with a clean system takes about 3-4 days to be clean. Smoke 2 days later and then have to wait about a week, and so on. The time it will take roughly doubles every time you smoke until it maxes at about 45 days to be clean. So if you are maxed out and you wait about 2 weeks and then smoke again, you're basically back to 45 days.
This also depends on the test. Most job drug tests only test down to about 100 nanograms, which isn't dead accurate but will pick up if you are a smoker obviously. Court-appointed tests can test anywhere down to 10-20 nanograms, which is very accurate, and can also detect high levels of water, and any other drug test liquids. You can not fool those tests, and drinking water and tea does nothing for getting weed out of your system at all. The ONLY way to get it out is time, because it is in your blood.
* Marijuana can be detected in urine for nearly a week after smoking. Blood tests can be more accurate, and it might take a month to be totally clear. Hair tests show every drug ever taken when that hair was growing - this is why you see so many drug addicts with shaved heads or buzz cuts, by the way. Also by the way: taking laxatives and drinking wacky chemicals won't "cheat" a drug test. It will just make you go to the bathroom!
* I don't usually smoke marijuana but I went to the comedy show and smoked a blunt. I smoked the blunt on February 29, 2008, and took a urine test for a job on Tuesday, March 11, and tested negative. My height is 5' 7.5" and I am overweight (254 lbs.), but I go to the gym 4-5 days a week and drink plenty of water.
I recall reading a while back that weed -- if you are a rare user -- usually stays in your system 3-4 days. But to be safe, I would say a 10-day "test window" after you last smoked will give you a negative result. If you are a regular user, you will definitely have to detox yourself for at least 30 days.
Also, when you take those drug tests, it stipulates that if there is any reason to believe that you have tried to deceive the test it would be treated as a positive and you won't be hired anyway. Therefore, I'm sure they also test for those substances that will give you a negative reading when they do the test.
* I don't smoke weed regularly, but only every few months, over the duration of about a week. Whenever I've had to do a drug test, I just drank plenty of water (lots!) on the night before the test -- and on the day of the test -- and it came back clean. I also take a hydrochlorothiazide pill and I'm sure that helps too.
* Most of the answers on this blog are incorrect. It depends on how often you smoke, and on your metabolism. If you smoke once a week for 3 months and stop, you'll be clean within 3-5 days. If you smoke daily for 3 months and then stop, but exercise daily, you're looking at 2-3 weeks. The best way to find out is to purchase a few urine tests. They're cheap, and you can use them at home.
I've never heard of a blood test for marijuana.
There are ways to beat a hair test. Cut your hair to a reasonably short length and use Aloe Rid daily. Soak your hair in an astringent and wash with Tide. Again, you can buy hair test and mail it in.
It doesn't take months.
* I know the best way to get bud out of your system in under 3 days. All it takes is for you to