How long does cannabis stay in the body? Expert explains after Mohammad Nawaz's ICC ban

The ICC's decision to ban Pakistani cricketer Mohammad Nawaz after he tested positive for Carboxy-THC has once again brought cannabis into the spotlight.

As the drug is increasingly being legalised or decriminalised in several countries, one scientific fact remains unchanged: while the effects of cannabis may wear off within hours, traces of the drug can remain in the body for weeks.

Nawaz's sample did not contain THC itself, but Carboxy-THC, an inactive metabolite formed when the body metabolises tetrahydrocannabinol (THC), the principal psychoactive component of cannabis. This explains why a person may no longer feel "high" but can still test positive in a doping test.

THC can remain in the body for weeks

"THC is highly fat-soluble, which means it is stored in the body's fatty tissues and released slowly over time," says Dr Meenakshi Jain, Senior Consultant, Psychiatry, Amrita Hospital, Faridabad.

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"Urine tests can be be positive in occasional users for three to seven days, while regular users can stay positive for three to four weeks, and in some cases longer, depending on body composition, metabolism and frequency of use."

"A positive test does not mean you are currently intoxicated. It means you have been exposed to it previously."

According to Dr Jain, anti-doping tests are designed to detect evidence of previous cannabis exposure, not whether someone is under the influence at the time of testing.

Why athletes can fail a doping test long after using cannabis

Unlike alcohol, which leaves the body relatively quickly, cannabis leaves behind metabolites that remain detectable long after its psychoactive effects have disappeared.

"The lesson for professional sport is simple," Dr Jain says.

"Anti-doping laboratories do not test whether an athlete appears intoxicated on the day of competition. They test for biological evidence of previous exposure."

"This means that cannabis leaves a biochemical footprint that can last far beyond its psychological effects. It can remain for several weeks, turning a momentary decision into a career-defining consequence."

Cannabis remains the world's most widely used illicit drug

The World Drug Report 2025, published by the United Nations Office on Drugs and Crime (UNODC), says cannabis remains the world's most widely used illicit drug, with more than 240 million people reporting annual use.

At the same time, scientific evidence continues to highlight the health risks associated with frequent or high-potency cannabis use.

Cannabis can affect mental health and cognitive function

"From a psychiatric point of view, cannabis is far from being a harmless recreational drug," says Dr Jain.

"When used repeatedly, it can impair attention, memory, decision-making and reaction time, functions that are essential to elite athletes."

She adds that some individuals may be particularly vulnerable to its effects.

"People with a family history of mental illness are especially vulnerable. Cannabis can trigger panic attacks, worsen depression or trigger psychotic episodes in those with vulnerable brains."

Studies published in journals such as The Lancet Psychiatry have consistently shown an association between frequent or high-potency cannabis use and an increased risk of psychosis, anxiety disorders and cognitive impairment, particularly among adolescents and young adults.

A positive test is not the same as being intoxicated

While the immediate effects of cannabis typically wear off within hours, the body's biology tells a different story.

As Dr Jain explains, a positive anti-doping test does not necessarily indicate that a person is intoxicated. Instead, it confirms previous exposure to cannabis, sometimes weeks after it was consumed.

For elite athletes, that distinction can have significant consequences, as anti-doping rules focus on biological evidence rather than visible impairment.