Tag Archives: Testing

How Long Does Weed Stay In Your System?

By: Sera Jane Ghaly

The amount of time that weed stays in your system depends on the user and how frequently they smoke. There are other factors involved, too, such as how it is being tested. THC binds the longest to the hair follicle and to saliva for the least amount of time. 

THC has a cumulative effect in the body and includes other factors such as the metabolic rate. However, as a general rule of thumb, this is how long cannabis stays in the system.

THC in urine. 

Photo credit: Smoking Pagoda
The most common way to test for THC is in the urine because it is the cheapest method and has a long detection period. However, the length of time will vary depending on the frequency of use because of the cumulative effect of THC. 

  • Someone who has smoked for the first time can test positive for THC for up to 8 days in urine.
  • Someone who smokes frequently can test positive for THC for up to 15 days in urine.
  • Someone who smokes heavily can test positive for THC for up to 30 days in urine.
  • Some heavy marijuana smokers have been tested positive for up to 45-90 days in urine after stopping smoking cannabis.

As a guide, if you´re a heavy smoker, chances are THC will remain in your urine for up to a month after stopping. This is also the most likely way you’ll be tested for weed in your system.

THC in saliva.

THC lasts the shortest time in the saliva. This is the method most often used by road police in checking for drugged drivers. It starts to test positive about 1 hour after smoking and can remain positive in saliva for up to 12 hours.

THC in hair. 

In the case of hair follicles, THC binds for the longest period of time. A single use of cannabis can test positive in the hair for up to 7 days, and most hair follicle tests are for a 90 day period. However, it is not always certain that cannabis actually binds to the hair follicle, so this method is hardly ever used.

THC in blood. 

THC is hardly ever measured from the blood because the metabolite of THC doesn´t bind to the blood for very long. As a result, testing cannabis in the blood only detects recent use. 

How to pass a urine test

Unfortunately, there´s no certain way to pass a urine test if you´re a heavy smoker. There are products that can be purchased solely for the purpose of cleansing urine, but their reliability is questionable. 

The most scientific way to pass a urine test is to drink a lot of cranberry juice or a lot of fluids. Adding more water to the system will naturally dilute whatever is in your urine. 

But the surest way to pass a urine test is to stick safely and generously to the time guidelines! 

How long other chemicals stay in the system

While on the topic, it´s interesting to note how long other chemicals remain in the system after use. 

  • Heroin can be detected in blood and saliva for up to 12 hours, and in urine for up to three days.
  • Amphetamines can be detected in blood and saliva for 12 hours after use and in the urine for 1-2 days after use.
  • A standard drink of alcohol can be detected in the body for only about 5 hours after use (the more that is consumed, the longer the it takes to metabolize, but is the shortest detection time of them all).


So many employers these days are testing their employees for drugs. However, it is easier to get away with having a problem with amphetamines than it is to be a cannabis smoker. Given the technology that is available, shouldn’t there be some leniency towards frequency of use with cannabis? It is legal now, after all. In fact, after legalization, the risk to the workforce if drug testing is not altered is extreme. It could result in a giant loss for the workforce in the USA.

Cannabis stays in the system longer than almost all other chemicals in the body because of it´s cumulative effect. However, everyone knows that you´re not necessarily high 12 hours after use. The best advice to smokers out there afraid of the ever prevalent urine test, stick to jobs that don´t require it!
Original article can be found here