How Long Does Marijuana Stay In Your System?

how long does weed stay in your system

There are many people who ask the question “how long does marijuana stay in your system?”  Unfortunately, the answer to this question is not simple and straightforward, the fact is that if you want to use a drug test effectively, it is a question that requires an answer.

So let’s cut through the misinformation on the Internet and provide one!

Before we understand the period of time that marijuana lasts in the system, there are a couple of facts that you should know.

– The presence of marijuana is detected by a drug test through the presence of the active chemical THC or Tetrahydrocannabinol.  Technically, what is detected is known as THC-COOH (11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid).

– The time that marijuana stays in the system depends on the amount of marijuana intake and the frequency at which it is consumed.

– When you smoke marijuana, your body breaks it down like it would anything else.  The products of this breakdown are known as metabolites.  The main metabolite of marijuana is THC-COOH.  THC-COOH can be stored in the body in fat if you’ve consumed more than your body can get rid of at a given time.

– If you consume marijuana continuously, your system will be sort of “overloaded” with THC-COOH (which is not to say that you’ll be continuously high).  Some of that THC-COOH will be stored away in the fat since the body can’t get rid of it.  This means that the THC-COOH will be present in the system for much longer, as the body will have to play catch up at getting rid of the THC-COOH.  Think of it as the difference between eating a peanut butter sandwich and a KFC Double-down.  Both count as one meal, but one has far more calories and fat content.  Since the body can’t use the calories and fat content it’ll store them away.  Same with THC-COOH and someone who smokes a lot of marijuana.

– Marijuana drug testing can be conducted using saliva, urine, hair and sometimes blood as the sample.

– The specific window that you need to check for marijuana consumption depends on whether you are checking on someone who has tried for the first time or if you are testing someone who smokes a few times a week, or someone who smokes daily.

How Long Does Marijuana Stay in Saliva?

Marijuana does not stay in saliva for very long.  Most of the rules that apply to marijuana’s detection time in urine and hair do not apply to marijuana in saliva.  It can be detected by a saliva drug screen about an hour after intake. The accuracy of a saliva drug test (97%-98%) will decrease rapidly about 12 hours after the marijuana was consumed. So while a saliva drug test option may be useful if you want to find out if someone is high or if they were smoking yesterday, it is not an effective test for long term or less recent use.

How often someone smokes marijuana (for example, every day for 6 months, or just once) has no bearing on the results of a saliva drug test.

How Long Does Marijuana Stay In Urine?

The amount of time marijuana can be detected in urine depends on the amount and frequency of its consumption.  Marijuana can stay in the urine for up to two months in cases of very frequent, prolonged use.   Basically, the more you use marijuana, the longer it will remain in your urine.  If you have just tried marijuana, for example, and that was your only use, it will probably be out of your urine within a week.

Those who kick the habit after consuming the drug almost daily can still have THC traces in the urine for a month or longer.

Be sure when testing to wait for about 2 to 5 hours after consumption or last suspected conception for THC to appear in the urine though.

How Long Does Marijuana Stay In Hair?

When smoked, marijuana enters the bloodstream and as the blood nourishes the hair, the drug gets into the hair follicles too. As the hair grows, the hair follicles contain traces of THC that can confirm the intake of marijuana. THC can show up in hair about a week after consumption (it takes the hair bearing traces of THC that long to emerge from the scalp).

Drugs take a long time to deteriorate in the hair and therefore testing can be done many days after consumption. A standard laboratory will check up to 90 days but a court or another law enforcing institution can have hair analyzed for more than 3 months as well.  Special arrangements can usually be made with laboratories if inquiries are made.

While hair drug testing provides a good opportunity to confirm whether someone has been on marijuana, and has the largest detection window, the issue is that this drug is not one of the easiest drugs to hair test. THC, when it’s in your body, does not always bind successfully to the hair follicle. Therefore, it is possible that a semi-frequent user may get a negative reading on a hair follicle drug test while someone who had it just once a couple of weeks back may get a positive result. It is a bit of a toss up. The hair follicle drug test is therefore not considered to be as reliable for marijuana as it is for other drugs like cocaine (and for drugs like cocaine, and all other drugs tested for in a standard consumer hair drug test, hair follicle drug testing is actually found to be better at catching drug use than urine tests).

So while the question “how long does marijuana stay in your system” is a pertinent and popular one, there are all of the above factors to consider before an appropriate and correct answer can be given. Even though there is all this discussion about the whole question, if you are concerned, the best thing to do is to just go out there and purchase a home drug test and check out whether you or someone else test clean or not.

(Check out our home drug test product line here! We carry all of the tests profiled above in the chart.)

Anne Hamilton


  1. admin says:

    There are no hard fast rules as you can see in the comments by other folks here. One guy can always get clean in two weeks and then someone else is over 45 days and still testing positive. The only way to know is to test yourself … it is easy and cheap and will give you the answer with no guessing.

  2. cln says:

    i am 220lb i have a drug screen every two weeks for probation i am also lazy and dont exercise or really do much for that matter lol but i smoke about two joints and six days later i pass my drug test and i dont do anything to clean myself out !!! y boyfriend also smoked a joint and a day in a half passed a drug test for his cap classes he weighs about 160lb and didnt do anything to clean his self out and he smokes all the time i only smoke a few times a week so i hope my experiences help u and gives u hope that u will pass!!!

  3. JJ says:

    Hi there, i smoked once at new years with some friends, and had a urine screening today. I do work out and had lots of fluids. 23 Days passed since that day, before that i tried it occasionaly, not too often though. How are my chances of passing?

  4. admin says:

    Most likely you would pass if it has been 22 days since you smoked once.

  5. Walid says:

    just had a urine drug screen and there getting the results in about a week last time i smoked weed was 33 or 34 days ago i do it occasionally i am 5f5 120 pounds about 7% fat and high metabolism skinny will i pass?

  6. star says:

    ok if my first time smoking since may of 2012 was jan 1 2013 and i havent smoked since then and i have a urine drug test sometime possibly this week or next week do you think i should pass the drug test?

  7. Kay says:

    Hi there, I have not smoked in 2mnts and have to take a urine test I am 130lbs and smoked every other day and good stuff at that. what should I do to make sure I pass????

  8. admin says:

    I would think you will pass your test.

  9. admin says:

    Depends on what you mean by “occasionally” for your previous use. Only the test can give you the answer.