How Long Does Marijuana Stay in Your System?

Drug test, drops, and plant in vase all next to one another on green backdrop

Few topics in the judicial system and across society have been more polarizing than the journey toward legal marijuana use. After years of lobbying, marijuana, and cannabinoids have slowly been legalized across the United States. As of the writing of this article, 22 states plus the District of Columbia have legalized marijuana used recreationally, and thirty-eight states allow cannabis to be used for medical purposes. Support for legalizing cannabis has steadily increased since the early 1990s, and today, most people see it as having minimal societal effects while also being a revenue source for local governments. While the federal government has not yet recognized cannabis as legal, we believe it is inevitable. There is still, however, a lot to learn about how cannabis affects the body, particularly the psychoactive ingredient Tetrahydrocannabinol, known as THC.

From a law enforcement and employment standpoint, there is still heated debate over how long marijuana stays in a user’s system. In other words, how long is marijuana detectable in the body? We must learn more about how the body stores THC to understand this.

THC is absorbed into the body most commonly by inhalation or ingestion. The liver then metabolizes it, at which point about 85% is eliminated through feces and urine. The rest is stored in various organs around the body and in fat tissue. Over time, THC is released by bodily structures into the blood, metabolized by the liver, and eventually removed from the system. Because THC is fat soluble, it is stored in the fat tissue for extended periods.

Does Chronic Use Make a Difference?

Absolutely. It has been shown that the more consistently marijuana is used, the longer the detection time in the body. Mayo Clinic research shows that a single use of marijuana is detectable for up to three days, and moderate use four times per week is noticeable between five and seven days. Daily users, which would be considered chronic use, may be detectable for 15 days, and a heavy smoker using chronically may have THC detectable for greater than 30 days.² Of course, the frequency of use is only part of the equation. Other factors can also change how long THC is detectable.

Other Factors Affecting THC Detection Times

Several factors can increase or decrease the detection window – when THC can be tested in the urine. This will include the following:

  • The strain of marijuana
  • Dosage
  • Body mass
  • Acidity or alkalinity of urine (PH)
  • Urine concentration and
  • Organ impairment, particularly liver, and kidney

Why This Matters

The detection window for marijuana use is a hotbed issue, especially in the judicial system. If, indeed, marijuana use has a long detection window, users can fail a drug test even if they have not consumed the drug in the recent past. This has, of course, legal and employment ramifications. A 2006 National Drug Court Institute fact sheet³ calls much of the research surrounding the ubiquitous 30-day detection window into question. On the one hand, law enforcement is frustrated with the lack of clarity around what constitutes recent use. On the other hand, it offers guidance for drug courts to develop better testing guidelines that more accurately approximate the last use.

How We Test for Marijuana

There are many possible tests for marijuana consumption, and when used appropriately, detection can be relatively precise. Typically:

  • Urine tests detect THC for 3-5 days after use
  • THC is seen in the blood for up to 2 days
  • It is seen in saliva for up to 3 days
  • THC is often seen in the hair for 30 or more days. Sometimes up to 90 days

These timeframes can vary based on the concentration of the THC as well as chronic use.

Can I Get Intoxicated or Fail a Drug Test from Secondhand Marijuana Smoke?

While the smell of marijuana can be very pungent and unmistakable, it is highly unlikely that someone will become impaired or fail a drug test unless this exposure is concentrated and prolonged. Most of the THC the user smokes is absorbed by the body, and what is exhaled typically contains very little THC.³ Studies have shown that it would take extreme exposure to secondhand marijuana smoke to become impaired and ultimately fail a drug test. This is not to say that there is no exposure to THC; simply that, if your levels are low enough, it is unlikely to have an effect.

It is worth noting, however, that the other compounds in marijuana smoke may cause damage to the heart and cardiovascular system, much like secondhand tobacco smoke does. This has not been fully understood, but preliminary rodent-based studies have shown this is a possibility. This is particularly problematic for those suffering from breathing concerns, like asthma or COPD, and children during their developmental stages.

Is There a Way to Clear Marijuana from My Body More Quickly?

THC is processed and metabolized in the liver, so anything that increases its capabilities can more quickly reduce the amount of the drug in your system. Healthy habits, including proper diet, exercise, and good hydration habits, all allow the liver to work most efficiently. Be mindful, however, that every person is different, and it is virtually impossible to know how quickly marijuana will be eliminated from the system.

Why Do You Ask?

While many of you are interested in knowing more about the psychoactive compound of marijuana, there are likely some readers looking for ways to get around or beat, a drug test. For those that fall into the latter category, this can be a crucial moment in your life or that of somebody around you. Marijuana use, just like other substance use, can escalate to the point of causing significant consequences in the life of an individual. Known as marijuana use disorder, the CDC estimates that about 3 in 10 people that use marijuana suffer from this condition. Marijuana use disorder can also exacerbate co-occurring mental health diagnoses, jeopardizing mental health stability and potentially resulting in mental health decompensation or crisis.

In other words, problematic usage is not limited to illicit and highly addictive drugs; people become dependent on legal substances, like alcohol, prescribed medications, and marijuana, too. If you have found yourself scrambling to beat a drug test and walk a fine line between getting a recreational high and losing something near and dear to you (relationships or jobs) or even finding yourself in compromising positions due to marijuana use, it’s time for help. Often, it’s tough to see our own problems, and these are the times when you can lean on the support of mental health facilities like The Sylvia Brafman Mental Health Center to understand if you could benefit from mental health treatment.

Often, the most challenging part of the recovery process is the first step – asking for help. This requires great strength and humility in admitting that you may have a problem and need help to correct it.


  3. Herrmann ES, Cone EJ, Mitchell JM, et al. Non-smoker exposure to secondhand cannabis smoke II: Effect of room ventilation on the physiological, subjective, and behavioral/cognitive effects. Drug Alcohol Depend. 2015;151:194-202. doi:10.1016/j.drugalcdep.2015.03.019.

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