Any cannabis user has likely pondered how to get THC out of the body at some point or another. Unfortunately, the short answer is that there is no surefire way to completely “get weed out of your system” at a quicker than normal rate. Because of the way the body metabolizes THC, it stays in the blood, hair and urine for many days or even weeks, according to Medical News Today. The good news is that it will eventually leave the body if users completely abstain from consuming weed for long enough. But the question on how long that will take has a rather complicated answer.