There’s two very important reasons someone would want to know how long tetrahydrocannabinol (THC), or the active ingredient that makes marijuana users high, stays in your system. One is getting offered your dream job, only to learn you have to take a routine drug test, if you use marijuana. The other is if there’s a legal threshold amount still in your system and you get pulled over by police, who ask you to take a roadside sobriety test, because they suspect you are high. In either case, you are sure to be a little panicked.

Factors That Determine How Long Cannabis Stays in Your System?

How Long Does Marijuana Stay in Your System? | Broomfield DUI Attorney

How Long Does Marijuana Stay in Your System? | Broomfield DUI Attorney

Most experts will say Cannabis can stay in your system for up to 30 days. However, the answer is more complex than that, because everyone’s level of sensitivity and ability to store THC is different. The following are factors that determine how long THC will stay in a person’s system:

  • Biological make-up varies from person to person.
  • THC stores up in fat cells, so THC will stay or store longer in an obese person’s system than a skinnier person’s system.
  • Frequency of use also determines how long THC stays in the system.

What Method of Testing Detects THC in Your System?

In Colorado, the law stipulates that a driver with 5 nanograms of active THC in their system (blood) can be prosecuted for driving under the influence of drugs (DUID). There are several ways to test for THC in a person’s system, including taking and testing a sample of a person’s:

  • Urine
  • Blood
  • Hair
  • Breath
  • Saliva
  • Fingernails

Even though each method has certain advantages, urine tests appear to be the test of choice by most private employers, and the sole test recommended for law enforcement as well, according to the Substance Abuse and Mental Health Services Administration (SAMHSA). Interestingly enough, urine tests do not measure the of THC present in the system, but instead measure the levels of metabolite THC-COOH.

How Does Marijuana Impair Drivers?

Like alcohol, a driver can’t really perceive or judge their level of impairment, which puts themselves and others on the road at risk. The following are ways using marijuana impairs a person’s ability to drive, according to the National Institute on Drug Abuse:

  • Impairs judgement and the ability to judge distances and speed of other vehicles.
  • Impairs coordination making it difficult to react to regular driving conditions.
  • Impairs reaction time making it difficult to make simple turns at intersections or hit the brakes at the appropriate time.

The National Institute on Drug Abuse even acknowledges that there have been studies done that have found a direct correlation between THC concentrations in the blood and impaired driving. Marijuana is also the most common drug found in drivers who have been involved in motor vehicle crashes and fatal crashes.

Latent Impairment Impacts from Marijuana

One research study suggests that those who take cannabis for sleeping disorders, such as insomnia, actually have different results that depend on each individual. The study found the following findings:1

  • Those who suffer from depression slept better with cannabis use.
  • Those who suffer from anxiety slept better with cannabis use.
  • However, those not suffering from anxiety or depression may not get the beneficial effects from cannabis for better sleep, and may in fact end up harming their sleep.

So, in some cases cannabis can be seen as inhibiting sleep and may in fact cause drivers to be drowsy the following day. Driving drowsy is in fact a sign of impairment, and if the THC levels in your body are high enough, you may still be drugged and could be charged with a DUID.

Contact a Broomfield DUI Attorney at The Datz Law Firm

Getting arrested and charged for a DUID can be a scary ordeal, and you might be overwhelmed with emotion, fear, and frustration immediately afterwards? If so, the Broomfield DUI Attorney at The Datz Law Firm is compassionate and ready to give you a clear outlook on what you’ll need to do to preserve your rights. The Broomfield DUI attorney will put you at ease and explain all the nuances that can change the outcome of your case – whether for better or worse. Our aim, however, is to get you the most favorable outcome for your case as possible.

We can assist in every aspect of your DUI/DUID case, including matters involving the Division of Motor Vehicle with regard to the suspension or revocation of your driver’s license. For a free, no-obligation consultation to meet and learn how we can best help your case, call (720) 256-2404, or use the form at the top of the page to email us.


1“How Much Does Marijuana Affect Sleep?” published in Newsweek, Sept. 2017.