Why Does the Body Hold On to THC for So Long?

A marijuana high typically lasts for a couple of hours, but the THC stays in your system much longer—as in, weeks longer. This fact can be annoying for anyone who has to undergo drug testing. Nobody wants to subject themselves to a 30-day pot detox just so they can keep their job or avoid legal trouble.

So why does THC stay in your system for so long? And is there anything you can do about it?

What Is THC?

For a quick primer, THC is delta-9-tetrahydrocannabinol. It’s one of over 100 cannabinoids found in marijuana. Cannabinoids are the compounds that bind to the body’s natural cannabinoid receptors, and these interactions are what cause the well-known physical and physiological effects of marijuana.

For most marijuana users, THC is the most important cannabinoid; it’s the psychoactive compound that gets you high. But it’s also the compound that conventional urine, blood, and hair tests look for. That means it can come back to haunt you long after your smoke session is a distant memory.

How Long Does THC Stay Inside the Body?

If you’re a regular user, THC may be detectable in your system for a full month, sometimes longer. Some research has even detected cannabis a full 90 days after the user’s last toke. On the flip side, there are instances when THC is only detectable for about 48 hours after use.

Why such a wide spectrum? It appears that the detection time is largely related to frequency of use. The more often you light up, the longer the compound stays in your system.


Why Does THC Stay in the Body as Long as It Does?

Conventional drug tests don’t actually detect the presence of THC; they detect the presence of THC metabolites (the byproducts of metabolism). These metabolites can remain in the bloodstream much longer than the THC itself, and they’re easier to detect.

When THC enters the body, it’s broken down by the liver and converted into about 80 different metabolites. The main metabolites are THCCOOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol) and 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol).

The problem is that not all THC is metabolized at the same time. THC is a lipid-soluble compound, which means that it binds to fatty tissue in the body. This means an occasional user might quickly metabolize and expel all THC from their body, but a frequent user will have more THC stored in their fat. The THC is reabsorbed into the bloodstream and metabolized gradually, so it’s detectable in the system for much longer. Eventually, all of the THC and its metabolites are expelled via urine and stool.

Frequency of use isn’t the only factor that impacts how long your body holds onto THC. There are other variables that play a role as well, including:

Your age

Metabolism slows down with age, so it may take longer for your body to break down and eliminate metabolites as you get older.

Your gender

Women tend to have a higher proportion of body fat and may therefore hold on to THC for longer than men. Hormonal differences in men and women may also play a role.

Your body fat percentage

Because THC is stored in fatty tissue, excess body fat is associated with longer detection times.

The type of marijuana delivery system

Edibles are digested and metabolized more slowly than smoked marijuana, so the THC can linger in your system much longer when you opt for the brownie. Edibles also get you high for much longer.

The amount of THC in the cannabis strain

Your average cannabis strain can range from 10% to 25% THC. A cannabis concentrate (wax, shatter, etc…) can have a staggering 80% THC. The more THC you consume, the longer it will be detectable in your system.

Still, despite these variables, there are some average detection times that we can look to as ballpark figures.

  • First-time users – detection time of 5 to 8 days
  • 2-4 times per month – detection time of 11 to 18 days
  • 2-4 times per week – detection time of 23 to 35 days
  • 5-6 times per week – detection time of 33 to 48 days
  • Daily use – detection time of 49 to 63 days

Present THC vs Detectable THC

Just because someone has active THC metabolites doesn’t mean they’re currently using marijuana; as we previously established, THC can sometimes linger in the body for months. In the same way, just because a drug test fails to detect THC doesn’t mean that the body is free of this cannabinoid.

This is an important point to highlight because it serves as a reminder that drug tests aren’t foolproof. If you want to know whether or not an upcoming drug test will detect THC, try to find out what kind of test is being administered. Consider that:

  • Blood tests can only detect THC for about 3 to 4 hours after use.
  • Most saliva tests can only detect THC for about 24 hours.
  • Most urine tests can detect THC for about 3 to 30 days.
  • Hair tests can detect THC for up to 3 months.

So, if you’re going to get tested, you ideally want a blood or saliva test. Urine tests are the most common because they are easy to administer and reasonably accurate.

Hair tests are the worst because marijuana reaches the hair follicles via small blood vessels and can then linger on those follicles long after the hair has emerged on the scalp. Hair grows about .5 inches every 30 days, so the THC may still be detectable on hair that has grown to 1.5 inches over 3 months.

To make matters worse, hair tests are notoriously prone to false positives. That’s because conventional hair tests can’t distinguish between THC ingestion and environmental contamination. If a marijuana user touches your hair, the oils from their skin can transfer the THC to your hair follicles, triggering a positive result.

So even if THC can theoretically linger in your system for 30 to 90 days, that doesn’t mean a drug test will detect it. It all depends on the type of test, the accuracy of the test, and when the test is administered.


Can You Remove THC From Your System More Quickly?

You’ve probably seen plenty of online tips informing you how to “beat” a marijuana evaluation. And yes, while there is some evidence that zinc may produce a false-negative urine test or that over-hydrating may dilute the presence of metabolites in your urine, these techniques won’t actually remove the THC from your body—nor are they guaranteed to help you pass a drug test.

Likewise, you can’t flush THC from your system by drinking water or detoxing, at least not with great effectiveness. If THC was simply metabolized and expelled from the body, it might be easy to speed up the process. But remember, those metabolites cling to fatty tissue, often for weeks at a time, and all of the detoxing in the world won’t give rid of them.

The metabolites will leave your body when they’re good and ready, so just be aware of that if you’re subject to drug testing. The best thing you can do is avoid excess use, stop using cannabis in the weeks leading up to a drug test (if you know it’s coming), and pray that you don’t receive a hair follicle test.

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