Research states that brain receptors called cannabinoid 1 receptors begin to return to normal after 2 days without marijuana, and regain normal functioning within 4 weeks of stopping the drug. Once THC has been metabolized and eliminated, CB1 receptors begin to be upregulated to their normal level of availability. Upregulation after a single or occasional dose of cannabis occurs rapidly. Most people don't feel affected the next day.
Chronic smoking of cannabis (marijuana, hashish) can cause dependence. Rodent studies show reversible downregulation of brain cannabinoids CB1 (cannabinoid receptor-like receptors) after chronic exposure to cannabis. However, it is unknown if downregulation occurs in humans who chronically smoke cannabis. Here we show, using positron emission tomography imaging, the reversible and regionally selective downregulation of CB1 cannabinoid receptors in the brain in human subjects who chronically smoke cannabis.
Downregulation correlated with years of cannabis use and was selective for cortical regions of the brain. After approximately 4 weeks of cannabis abstinence continuously monitored in a safe research unit, CB1 receptor density returned to normal levels. This is the first direct demonstration of the downregulation of the cortical CB1 cannabinoid receptor as a neuroadaptation that can promote cannabis dependence in the human brain. Brain receptors return to normal function.
Memory, mental acuity and attention span improve. It takes approximately 3 weeks for THC to leave your system. Therefore, your cannabis tolerance break should last at least 21 days. If you stop using cannabis, your brain can recover.
And it does so impressively quickly, usually in a matter of weeks.
