Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis that gives users a “high.” When you smoke, vape, or ingest weed, THC enters your bloodstream, crosses into your brain, and attaches to cannabinoid receptors. This triggers the release of dopamine and creates the classic effects recreational marijuana users seek like euphoria, relaxation, altered senses of time, and even hallucinations at very high doses. The rate of THC metabolism depends on factors like how much body fat a person has, genetics, sex, and prior history of cannabis use. In occasional marijuana users, detectable THC metabolites typically clear out within 3-5 days. But, in heavier, chronic consumers, THC lingers in the body for three weeks or longer before dropping below drug test cutoff levels.
THC absorption after smoking, vaping, or eating edibles
what is thc? Smoking and vaping cannabis causes THC to enter the bloodstream almost immediately through absorption in the lungs. Users start feeling high within seconds to minutes after inhaling. With edibles and drinkables, absorption happens more slowly. THC is processed through the digestive system, so effects don’t set in for 30 minutes to 2 hours. THC blood levels may ultimately reach higher peaks with ingestion compared to inhalation.
THC distribution to fat cells and organs
Once in the bloodstream, THC quickly distributes to body tissues. The lipophilic or fat-soluble nature of THC leads it to accumulate in fat cells and highly vascularized organs like the brain, liver, kidneys, spleen, and lungs. THC easily crosses the blood-brain barrier where it activates CB1 receptors and triggers dopamine release. Distribution explains how smoking just a fraction of a joint creates cerebral effects within minutes. THC also avidly binds to plasma proteins inside red blood cells, although lasting just temporarily before breaking free again. It helps expand the volume and depth of distribution.
Excretion in urine and feces
Inactive carboxy-THC metabolites like THC-COOH don’t stay in the body forever. Eventually, metabolites exit mainly through the urine and feces for elimination from the body. Traces also get excreted in sweat, saliva, and hair but in much lower amounts. THC itself directly exits through respiration since unlike water-soluble compounds, it cannot break down for easy renal disposal.
How long does THC stay in your system?
The approximate timeline for how long weed stays in your system depends on usage levels.
- Occasional Users (1-3 times per week) – 3 to 8 days
- Moderate Users (4-10 times per week) – 11 to 18 days
- Chronic Heavy Users (10+ times per week) – 30 to 45 days
- Regular Consumers Using Oral Products – 30 to 45 days
But again, many variables affect THC clearance rates like genetics, lifestyle factors, dose size, and testing method. For urine analysis, the standard cutoff is 50 ng/mL of THC-COOH. Blood tests look for 5-10 ng/mL of active THC. And hair testing detects usage patterns from one month (1.5 inches) to 90 days (3.9 inches). While urine and blood work only detect recent use, hair tests capture months of cumulative long-term use. Hair follicles retain traces of fat-soluble chemicals like THC that gradually build up in keratinized tissue over time. An occasional puff won’t show up. But, weeks of repeated smoking potentially leaves enough residue to trigger positive results for up to 3 months.