Cannabis in Blood: How Long Does THC Stay Detectable?

Cannabis usually stays detectable in blood for about 1 to 2 days after a single use, and up to 7 days or longer with heavy, daily use. Delta-9-THC peaks in blood within minutes of smoking and clears quickly, while the metabolite carboxy-THC (THC-COOH) lingers longer. Your dose, frequency, body fat, and the lab's cutoff level decide the exact window.

How long does cannabis stay in your blood?

The blood detection window is shorter than urine or hair, so a blood test mostly reflects recent use. Typical ranges look like this:

• One-time or occasional use: 1 to 2 days, sometimes up to 3 days.
• Moderate use (a few times a week): 2 to 5 days.
• Heavy daily use over months or years: 7 days, and in some chronic cases up to 30 days.

These are general ranges, not guarantees. Two people with the same habit can test differently on the same day.

How fast does THC peak in blood?

Smoked or vaped THC hits peak blood concentration within 3 to 10 minutes, then falls by roughly 90 percent within the first hour or two. That fast drop is why blood testing is used to look for very recent use.

Edibles behave differently. They peak later, usually 1 to 3 hours after you eat them, with a lower peak but a longer tail of detectable THC.

What changes how long THC stays in your blood?

No single number fits everyone. The main factors are:

• Frequency and dose: daily, high-dose users build up more THC and metabolites.
• Method: dabbing and concentrates deliver a bigger dose than a small joint.
• Body composition: THC stores in fat tissue, so higher body fat can extend release.
• Metabolism: liver enzyme activity, age, and genetics affect clearance speed.
• Test cutoff: a lab looking for 1 ng/mL finds far more positives than one using 5 ng/mL.

Blood vs urine vs saliva: which window is longest?

Different specimens tell different stories. A blood test is the shortest window, while urine and hair reach back much further.

• Blood: about 1 to 2 days for casual use.
• Saliva: roughly 1 to 3 days.
• Urine: about 3 days for one-time use, 30 days or more for chronic users.
• Hair: up to 90 days.

Does one hit of cannabis show up on a blood test?

Possibly, if the sample is drawn within a few hours. A single puff can push THC above common detection cutoffs for a short time, then fall below them within hours to a day.

Do edibles stay in blood longer than smoking?

Edibles often produce a longer detectable window even though peak levels are lower. The liver converts THC into 11-hydroxy-THC, which is more potent and clears more slowly.

Can you flush THC out of your blood faster?

There is no proven way to speed THC clearance from blood. Drinking water, sweating, and intense exercise do not reliably lower blood THC and can be risky if you overdo them.

Time is the only dependable factor. How much time depends on how much and how often you use.

Does a positive blood test prove impairment?

Not exactly. Detectable THC in blood shows use, not necessarily current impairment, and some states set a legal threshold such as 5 ng/mL for driving cases.

If you face a drug test for work, court, or medical reasons, treat any home remedy with caution and ask a healthcare provider about your specific situation.