How Long Does THC Stay in the System?

Knowing how long THC, the psychoactive cannabinoid, stays in your system is important for just about every cannabis user–—from the veteran to the novice. Whether you’re looking to take a tolerance break or a possible drug test looms in your future, it’s always smart to plan ahead when enjoying the ganja. So, the first, if not most important, question that comes to mind is: how long does it stay in your system?

To understand this answer, we need to define the players. What THC is, what it isn’t, clarify what we mean when we say “your system,” and establish a general timeline based on personal factors.

Sounds like a lot, doesn’t it? Well, take a deep breath. It isn’t. Cannabis works hard to relax your worries and bring total bliss to your everyday life––don’t disturb those efforts by conjuring an undue sense of anxiety.

Understanding What THC Is

You might know THC as one of the two most abundant cannabinoids in the cannabis plant––along with CBD. The THC molecule has gotten mankind baked for hundreds of years. But, when looking at a raw hemp plant, you aren’t seeing activated THC, not yet. Cannabis molecules pulled directly off the stem are actually THCA. This precursor molecule is non-psychoactive.

To become its activated form, THCA needs to get decarboxylated. Don’t worry; that’s about as sciencey as we’ll get today. Decarboxylated just means set on fire. So, when you light a joint or bake some buds, the heat from the lighter or oven converts that THCA into psychoactive THC. This THC molecule enters your bloodstream and dances with the CB1 receptors in your endocannabinoid system.

A Brief Introduction to The Endocannabinoid System

Inside your body, right now, is a network of receptors that are innately designed to process cannabinoids. Discovered only recently, the endocannabinoid system is what’s at work when you feel THC’s euphoric effects. Whether from digesting or inhaling cannabinoids, the body ushers these compounds through the bloodstream and steers them towards the endocannabinoid system’s CB1 and CB2 receptors.

When we’re investigating THC’s effects on the body, CB1 receptors are the main ones at play. There are fewer CB2 receptors inside the body, and most of them are condensed around periphery nerves. CB2 receptors engage CBD and not THC. On the other hand, CB1 receptors are focused in the brain’s neural network, which explains THC’s psychoactive effects when smoked or eaten.

Everyone Processes THC Differently

Have you ever enjoyed cannabis with a friend, and both of you experience drastically different effects? They claim to have the munchies while you are too focused on a task to think about anything else. They feel a vibrating sensation in their toes while you lose track of your thoughts in a fit of giggles. This dichotomy is due, in large part, to the fact that everyone processes THC differently.

How your body interacts and engages with THC is predetermined by a series of personal factors. These factors include your tolerance level, what you’ve eaten that day, your fitness level, your hydration, and several others. While these factors dictate your euphoric state, they influence how long THC stays in your system. So, understanding some of these factors can guide you on how long you can expect a positive result on a THC drug test.

General Fitness Level

Once your body processes THC, it stores the molecules in your fat cells. While the science of why the body does this is still inconclusive, the fact that the body uncharacteristically hoards THC adds to the molecule's mystical meaning. Once inside the fatty tissue, the cannabinoids linger until the fat is burned through either exercise or caloric deficit. The body then processes THC molecules out of the body through the bloodstream. While the science has yet to prove it, many long-time users who’ve quit cannabis report having “flashbacks” while working out. The stored THC gets one last hoorah, so to speak.

So, if you’ve already guessed, people with less fatty tissue process THC quicker than those with more fatty tissue. One way to speed up the process is to take up a cardio-focused workout routine. This will burn fat which will, in turn, rid the body of THC sooner.

Metabolic Rate

Related to how much fatty tissue your body naturally stores, your metabolism also significantly determines how long THC stays in your system. For those who don’t remember health class from high school, your metabolism is a series of processes that convert food into energy. When we’re younger, our metabolism is quicker, so fat develops slower, we stay lean, and we tend to eat ravenously. But as we age, our metabolism slows down, resulting in food taking longer to process through our body. This lengthened process can also stretch the amount of time THC stays in your system. So, those with quicker metabolisms can see THC process out of their bodies faster than those with slower metabolisms.

How Long Does THC Show Up on a Drug Test?

If you have a drug test looming in the future, it’s best to know a rough timeline for how long THC stays in your system. While, of course, these factors are all dependent on personal factors unique to you, some studies shed some light on this timeframe.

Studies have shown that 80%-90% of the compound has left your body after five days;1 THC can still linger in your urine for a few weeks. As for hair, the general rule is that THC stays in hair for around 90 days.

Sharma P, Murthy P, Bharath MM. Chemistry, metabolism, and toxicology of cannabis: clinical implications. Iran J Psychiatry. 2012 Fall;7(4):149-56. PMID: 23408483; PMCID: PMC3570572. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570572/