Five main factors determine how long THC (tetrahydrocannabinol) stays in your system:

1. How much THC you have taken.
2. How regularly you use THC.
3. The method by which you take THC.
4. The other cannabinoids and terpenes that you combine THC with.
5. Activity levels and food deprivation.

Here’s everything you need to know about how long THC stays in your system for, in the short, medium and long term.

THC in the Short-Term

THC can have short term and immediate effects. When you breathe in THC, such as through smoking, vaporizing, and inhalers, it passes through the lungs and has an immediate effect. This effect usually lasts anything from 1 – 2 hours to 3 – 4 hours, depending on how much has been smoked/vaped/inhaled. Small doses of THC are not likely to last longer than a couple of hours, whereas a large amount of THC (e.g. using a THC concentrate through a dab rig) can last longer – 3 – 4 hours, or even 8 hours if a potent concentrate has been used.

Cannabinoids like tetrahydrocannabivarin (THCV) can actually block THC’s psychoactive effects in low doses, and exacerbate it in higher doses. THCV is found in varieties like Doug’s Varin, Durban Poison and Girl Scout Cookies (GSC). This could be one reason why cannabis varieties high in THCV can have powerful but short-lasting effects (around 1 hour).

When it comes to cannabidiol (CBD), even though it can dampen THC’s psychoactivity, it may also help THC stay in the bloodstream for longer periods of time. THC is metabolized quite rapidly, but CBD could slow down the metabolization of THC as it is preventing THC from binding to CB1 receptors.

When taken as a tincture and sublingually, the effects of THC can last longer – around 6 to 8 hours. If a lot of THC-rich tincture has been used, the effects can last well into the next day. Tinctures usually take effect within 15 – 30 minutes, although some have reported effects kicking in after 1 hour.

The effects of edibles don’t tend to kick in until 1 – 2 hours after ingestion, but the effects can be a lot longer-lasting and powerful. This is because, when eaten, THC passes through the liver and then into the bloodstream, and is metabolized into the more powerful 11-OH-THC along the way. This means that the effects of edibles can last around 8 hours, and even, 12, 14 or the next day.

THC in the Medium Term

The effect of small doses of THC don’t tend to last long, and even larger doses of THC are metabolized rather quickly, meaning that a deadly overdose on cannabis alone is not practically possible.

However, the after-effects of high amounts of THC (called the “weed hangover” or the “stoned-over”) – which can include detrimental effects on short-term memory and hand-eye coordination – can be felt. These after-effects do not usually affect those who take cannabis in controlled doses (such as medical marijuana patients), but those who are using high amounts of THC for recreational purposes may feel the effects into the next day.

THC in the Long-Term

As THC binds to fat cells, it tends to stay in the body for quite some time. For regular users, THC can remain detectable in the body for around 30 – 35 days after last use. This means that, if you use THC-rich cannabis regularly, it will stay in the body for up to 35 days, even if you use no cannabis in those 35 days. “The plasma half-life of THC is 1 to 3 days in occasional users and 5 to 13 days in chronic users.”

For those who rarely or occasionally use cannabis (less than 3 times per week), THC is detectable in the blood, urine or saliva 3 – 7 days after last ingestion. Those who use cannabis regularly may find that THC is detectable in their body for 10 – 35 days after last ingestion. If the test uses hair follicles, THC is detectable for up to 90 days after last ingestion. The cutoff for most cannabis urine tests is 50ng/ml of THC-COOH or 11-OH-THC (THC metabolites), although they can be set to be more sensitive.

Is There Any Way to Speed Up the Processing or Metabolization of THC in the Body?

Fat is notoriously stubborn, and compounds that attach themselves to fat tend not to be easily moved. This is because the body naturally stores fat as an energy source for emergency situations, which is why having a body fat percentage that is too low (less resistance to cold and disease) or too high (strain on the heart and diabetes) can be detrimental to health.

Regular exercise, plenty of water, a healthy diet, zinc, and green & herbal teas may flush THC out of the body more quickly, but there is no guarantee that this will work for everyone. Activated charcoal capsules are another potential solution, but this should be avoided in most instances as it can interfere with the absorption of many medications, vitamins and minerals.

If You Want to Eliminate THC From Your Body

• Stop using THC-rich cannabis!
• Drink plenty of fluids, in particular water and green & herbal teas. Detox teas may help as well.
• Zinc supplements can help.
• Exercise regularly.
• Eat plenty of fruit and vegetables, avoiding too many fatty foods.
• Activated charcoal capsules may help, but be careful if you use other medications, as activated charcoal can interfere with absorption of medications.
• Remember that there is no sure-fire way of ridding the body of THC quickly, and everyone’s metabolism is different.