THC, the main active ingredient in Marijuana, is what stays in ones system. THC is stored in the fatty tissues in the body. Therefore, THC can stay in your system for months after use. THC can only be detected for a certain amount of time despite being stored in body fat. Rather than looking for THC directly, drug tests, such as urine tests, look for 9-carboxy-THC, the by-product of your fat tissues metabolizing THC.
The length of time THC stays in one's system depends on the frequency and quantity of marijuana the user consumed. For example, frequent users, defined as those who use several times a week, can show evidence of THC for up to three months. Infrequent users commonly have detectable TCH contents up to 10 days after smoking. The speed in which THC leaves your body also depends on the speed of your metabolism and the half-life of THC. Different from most substances, the half-life of THC can vary depending on when it's used, and who is using it. The half- life of THC varies within a period of 1-10 days, contributing to the difficulty of marking its elimination time. A person's body weight, fluid intake, and general health conditions also play a role in the amount of time THC will stay in your system.
All in all marijuana's active ingredient, THC is stored in one's body for a significant length of time, depending on the regularity and amount of drug use, and the person's metabolism.