How long is THC detectable in the blood?

After a single use, THC is detectable in the blood for 1 to 3 days. In the case of regular use, active THC can be detected for up to 30 days in the blood. The detection threshold is about 1 ng/ml for active THC.

How quickly does the body eliminate THC?

The half-life of THC in the blood is about 1 to 3 days. The THC-COOH metabolite (measured in urine) has a half-life of 3 to 13 days. THC is metabolized in the liver into 11-OH-THC and then into THC-COOH, and eliminated through urine and feces.

Can THC elimination be accelerated?

THC elimination can only be accelerated to a limited extent. Regular physical activity, sufficient hydration (water), a healthy diet, and sauna can stimulate metabolism. Warning: shortly before a test, exercise can temporarily increase THC levels, as THC is released from fat cells.

How does THC elimination work in the body?

THC (delta-9-tetrahydrocannabinol) is metabolized in the liver by the cytochrome P450 enzyme system. First, the psychoactive 11-hydroxy-THC is formed, then the inactive THC-COOH. THC-COOH is liposoluble and stored in fatty tissues, which is why it remains detectable longer in overweight individuals or in cases of chronic use.

What is the difference between THC and THC-COOH?

THC (active delta-9-THC) reflects recent use and is measured in the blood. THC-COOH is the inactive degradation metabolite, detected in urine. During roadside checks, active THC is measured in the blood (threshold: 1 ng/ml), while workplace screenings generally test for THC-COOH in urine (threshold: 50 ng/ml).

THC threshold for driving – what does the law say in France?

In France, driving after drug use is prohibited and subject to zero tolerance: any trace of THC detected during a check is penalized, regardless of a concentration threshold. In case of an offense, you risk a fine, license suspension, and points deduction. Cannabuben products contain less than 0.3% THC.

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THC Elimination
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Calculate how long THC remains detectable in your body. Our calculator takes into account consumption frequency, body fat percentage, metabolism and test method for an individual estimate.

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Consumption frequency

Test method

Body fat percentage: 22%

8% (very lean)45% (obese)

Metabolism

Days since last consumption: 0

Today90 days

THC detection times at a glance

Test method	One-time	Occasional	Regular	Daily	Limit
Urine test	3–8 days	5–15 days	15–30 days	30–77 days	50 ng/ml (screening)
Blood test	1–3 days	2–7 days	3–14 days	7–30 days	1 ng/ml (active THC)
Hair test	up to 90 days	up to 90 days	up to 90 days	up to 90 days	0.1 ng/mg
Saliva test	1–3 days	1–3 days	1–3 days	1–7 days	25 ng/ml

Sources: Huestis (2007), Sharma et al. (2012), SAMHSA Guidelines. Information without guarantee.

THC elimination in the blood

Active THC (delta-9-THC) is broken down in the blood within hours. The road-traffic limit has been 3,5 ng/ml in blood serum since 2024. With one-time consumption, the value usually falls below the limit within 24–72 hours. With chronic consumption, active THC can remain detectable in the blood for up to 30 days.

THC-COOH in urine

In urine, THC itself is not measured, but the metabolite THC-COOH. This is detectable significantly longer than active THC. The standard limit is 50 ng/ml (immunological screening) or 15 ng/ml (confirmation analysis by GC-MS). Since THC-COOH is fat-soluble, the body fat percentage considerably influences the detection time.

Influencing factors

The THC detection time is influenced by several factors: consumption frequency (biggest factor), body fat percentage (THC is lipophilic), metabolic rate, form of consumption (smoking vs. edibles), THC content of the product and individual genetics (CYP2C9 enzyme polymorphisms).

Road traffic

Since April 2024, a THC limit of 3,5 ng/ml in blood serum applies in Germany (previously 1 ng/ml). For novice drivers in the probationary period and those under 21, zero tolerance continues to apply. With mixed consumption with alcohol (from 0,2 per mille + THC), stricter sanctions apply. Traffic checks use rapid tests (saliva); if the result is positive, a blood sample is taken.

Frequently asked questions about THC elimination

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Test method

One-time

Occasional

Regular

Daily

Limit

Urine test

3–8 days

5–15 days

15–30 days

30–77 days

50 ng/ml (screening)

Blood test

1–3 days

2–7 days

3–14 days

7–30 days

1 ng/ml (active THC)

Hair test

up to 90 days

0.1 ng/mg

Saliva test

1–3 days

1–7 days

25 ng/ml

THC EliminationCalculator

Enter your data

THC detection times at a glance

THC elimination in the blood

THC-COOH in urine

Influencing factors

Road traffic

Frequently asked questions about THC elimination

How long is THC detectable in the blood?

How quickly does the body eliminate THC?

Can THC elimination be accelerated?

How does THC elimination work in the body?

What is the difference between THC and THC-COOH?

THC threshold for driving – what does the law say in France?

THC EliminationCalculator

Enter your data

THC detection times at a glance

THC elimination in the blood

THC-COOH in urine

Influencing factors

Road traffic

Frequently asked questions about THC elimination

How long is THC detectable in the blood?

How quickly does the body eliminate THC?

Can THC elimination be accelerated?

How does THC elimination work in the body?

What is the difference between THC and THC-COOH?

THC threshold for driving – what does the law say in France?

THC Elimination
Calculator

THC Elimination
Calculator