How long does THC stay in your body?
THC is fat-soluble, so your body parks it in fat tissue instead of clearing it fast. Plasma half-life starts at about 1.5 to 4 hours during the first distribution phase, then stretches to a terminal half-life of 20 to 30 hours in casual users and up to 5 days in daily users. The metabolite carboxy-THC lingers longer than THC itself, which is why a urine test can stay positive for weeks after the high fades.
How Long Does Cannabis Stay in Your System?
What is the half-life of THC, step by step?
Half-life is the time your body needs to clear half of a substance from the blood. THC moves through two phases, and each phase runs on its own clock.
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- Distribution half-life: 1.5 to 4 hours. THC leaves the blood and spreads into tissue, fat included.
- Terminal half-life: 20 to 30 hours in people who use now and then. Daily users can push this past 5 days.
- Carboxy-THC half-life: about 3 to 13 days. This inactive metabolite is what most urine screens look for.
Half-life is not the same as a detection window. A drug test needs a detectable amount, not zero THC, so the window runs past the half-life math.
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Why the numbers vary so much
Dose, route, frequency, and body composition all shift the curve. Someone who takes one 5 mg edible and someone who vapes concentrate all day are not running the same timeline, even if both test positive.
Why does body fat store THC?
THC dissolves in fat and does not dissolve in water. Fat tissue holds it, then releases small amounts back into the blood over days or weeks.
- Adipose tissue acts as a reservoir, pulling THC out of circulation.
- Slow release keeps a low level of THC and metabolites in the blood long after use stops.
- People with more body fat tend to store more and clear it slower, though the effect differs from person to person.
This reservoir effect explains the gap between how long you feel high (hours) and how long a test can find THC (weeks).
How does convenience shape THC storage?
Convenience decides the dose, and dose decides how much lands in fat. A 10 mg gummy eaten alone delivers a set amount. A vape pen lets you hit it again without measuring. Same chemistry, different total load.
Convenient formats also change timing. Fast-acting edibles and nano-emulsified drinks hit in 15 to 30 minutes, while standard edibles take 30 to 120 minutes. People who feel nothing at 20 minutes often take a second dose, and that doubles the THC headed for storage.
- Vapes: quick onset, easy to repeat, hard to track total milligrams.
- Edibles and drinks: measured dose, slow onset, higher risk of double dosing.
- Pre-rolls and flower: shared dose, variable potency.
- Concentrates: high potency per hit, so a small amount delivers a large load.
Delivery route changes how fast THC reaches peak blood levels. It does not change where the leftovers go. Fat still takes them.
How long can cannabis show up on a drug test?
Detection windows depend on the test, your use pattern, and your body fat.
- Urine: 1 to 3 days after one use, 5 to 7 days for moderate use, 30 days or more for heavy daily use. Long-term heavy users can test positive for up to 60 to 90 days.
- Blood: hours to a couple of days, since blood levels drop fast.
- Saliva: about 24 to 48 hours.
- Hair: up to 90 days, since hair traps metabolites as it grows.
These are general ranges, not promises. Individual results swing wide.
What changes your storage and clearance time?
- Frequency of use: daily use builds a bigger reservoir than weekend use.
- Dose and potency: more THC in means more THC stored.
- Body fat percentage: more fat tissue means more room for storage.
- Metabolism and liver enzymes: CYP2C9 and CYP3A4 activity differs by person and by genetics.
- Age: clearance tends to slow with age.
- Route: inhaled THC peaks fast, while oral THC passes through the liver and produces more carboxy-THC.
Hydration and exercise come up a lot in this conversation. Water does not pull THC out of fat cells, and the research on exercise is mixed, with some small studies finding a brief rise in blood THC after workouts in chronic users.
FAQ
Can you flush THC out of body fat?
No. There is no proven method to clear stored THC on demand. Time is the main factor, and heavy users need more of it.
Do edibles stay in your system longer than smoking?
Not because of storage, but because of dose and metabolites. Edibles pass through the liver and create more carboxy-THC, and people often take larger doses in edible form.
Does a fast metabolism mean a clean test sooner?
Not on its own. Metabolism matters, but body fat, frequency, and dose carry more weight. A fast metabolism with daily high-dose use still clears slower than a slow metabolism with one-time use.
Is half-life the same as detection time?
No. Half-life measures how fast the body clears half the drug. A test looks for any detectable amount, which stays above the cutoff for far longer.
Bottom line
THC half-life runs from hours to days, and body fat stretches that timeline by holding THC and releasing it back into the blood. Convenient, high-dose formats raise total intake, which raises storage. If a drug test matters, plan in weeks, not days.