How Long Does Weed Stay in Your System?

How long does weed stay in your system? This is one of the most common questions cannabis users have. Well, it’s not such a simple answer. First, which system are we referring to? Second, every person has a unique physiology, so how long weed stays in your system will likely be different than your friends.

Overview: How Long Does Weed Stay In Your System?


Most people who want to know how long weed stays in their system because they may be facing a drug screening. Some people are simply genuinely interested in knowing the answer to this for that reason alone.

When you smoke weed, your body metabolizes THC very quickly. If you’re eating an edible, the process your body goes through is similar, although it takes much longer to feel the effects of the THC. With either method, it’s pretty close to impossible to stay high for several days. Your body is pretty effective at processing psychotropic THC quickly.

Nonetheless, cannabis leaves byproducts in your body called “metabolites,” which can stay in your body for a good amount of time dependent on a variety of factors. “Metabolites” stay in your body much longer because they’re stored in fatty tissue, despite the fact the THC is no longer active.

How Long Does Weed Stay In Your Blood?

THC stays in your blood for usually 1-2 days for infrequent users, and up to a week for heavier users.

How Long Does Weed Stay In Your Saliva?


How long weed can be detected in your saliva depends on a number of factors, however, you can accelerate the process by staying well-hydrated, frequently brushing your teeth, using mouthwash, and limiting fatty foods. But generally it won’t stay in your saliva for very long, usually 1-2 days, and no longer than a week for even the heaviest users.

How Long Does Weed Stay In Your System for a Drug (Urine) Test?


Since the majority of employer drug screens test your urine, most people want to know how long cannabis can be detected. Technically, cannabis doesn’t stay in your pee. It’s actually THC-COOH, which is short for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol. THC-COOH is the primary-secondary metabolite of tetrahydrocannabinol (THC), which forms in your body after consuming cannabis.

Nonetheless, how long traceable amounts of THC will stay in your system is difficult to pinpoint, as it’s highly dependent on your physiology (including body mass index and your metabolic rate). It’s also influenced by how often you use pot.

However, from research, we can provide some approximate time ranges. A National Institute on Drug Abuse and National Institutes for Health sponsored study confirmed the range is very different depending on how often you use. Researchers divided the test subjects into three groups correlating to use which they determined by on initial testing levels: (Low Use: 0-50 ng/mg, Medium Use: 51-150 ng/mg, High Use: 150+ ng/mg). This particular study only tested subjects for 28 days. Most subjects in the low and medium use groups eliminated THC-COOH in less than 28 days. For heavy users, cannabis was detectable in most subjects for more than 28 days.

Graph: How long does weed stay in your system?

Summarizing the available research, High Times breaks it down like this:

  • 1-Time Use: Most people will be clean in 5-8 days.
  • 2-4 Times / Week: Even if you’re a fairly frequent user (2 – 4x per week), the average is 11-18 days.
  • 5-6 Times / Week: If you’re a near (but not quite) daily user, most people will have weed out of their system in 33-48 days.
  • Daily Use: For chronic users, it can take 50-65 days, although it’s possible it could take even longer.

How Long Does Weed Stay In Your Hair?

Cannabis use can be detected by hair longer than anything else. In fact, it can theoretically be years. However, most follicle tests are looking for use up to 90 days prior. And, it’s not uncommon for weed to be detectable for 180 to 360 days. Hopefully, if you’re getting tested, they won’t be analyzing your hair.



Basically, the 30 days most people cite for how long weed stays in your system is an imperfect benchmark. The fact is the range can vary tremendously. For blood and saliva, though, it will be detectable for no more than a week. Urine and hair, of course, are a totally different story. Weed can stay in your urine and hair for a long time if you’re a chronic user. If you’re not a frequent user, the amount of time is far shorter.

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