The time that cannabis remains detectable in the human body does not have a single answer and varies drastically from person to person. The detection window, which can range from a few days to over a month, depends on a complex interaction of factors, with frequency of use being the most determining.

Drug tests, in fact, do not only seek tetrahydrocannabinol (THC), the main psychoactive component. They look for its metabolic byproducts, which persist in the body for a much longer period.

How the Body Processes the Substance

When cannabis is consumed, THC enters the bloodstream and travels throughout the body. As it passes through the liver, it is broken down into various substances, including an inactive metabolite called 11-nor-9-carboxy-THC (THC-COOH). It is this byproduct that most drug tests look for.

Unlike active THC, THC-COOH is liposoluble. This means it binds and is stored in the body's fat molecules. From there, it is slowly released over time, being mainly eliminated through urine and feces.

Factors Affecting Cannabis Stay in the Body

Several elements influence the time these metabolites remain in the system. Frequency and dose of consumption are crucial; chronic users and those consuming larger doses accumulate more THC-COOH in fat, taking much longer to eliminate the substance than an occasional user.

Additionally, individual metabolism, genetics (which affect liver enzymes), and the person's body fat amount play significant roles in the speed of elimination.

Detection Methods and Windows

The most common testing methods are urine, blood, saliva, and hair, each with distinct detection windows.

Urine Test: It is the most commonly used standard. According to a review from the Mayo Clinic Proceedings, detection in urine can vary from:

Occasional use: Approximately 3 days.

Moderate use: 5 to 7 days.

Daily use: 10 to 15 days.

Chronic use (multiple times a day): Over 30 days.

Blood and Saliva: In blood, the presence of active THC is short-lived, disappearing within a few hours. However, the metabolite THC-COOH can be traced in the blood plasma for up to 25 days in some cases.

Saliva tests usually detect recent use, ranging from one to three days for occasional users, but can reach up to 29 days in chronic users.

Hair Follicle Test: This method offers the longest detection window, being able to identify cannabis in the body for up to 90 days. However, research indicates that this method is more effective in detecting frequent users and may be less reliable for occasional use.

With information from El Planteo