There are several factors which determine the amount of time THC (the substance found in marijuana) will remain detectable in the system. The different factors involved in determining if you will test positive for a marijuana drug test after use are: Body Mass Index (body weight), metabolic rate, the amount of marijuana used, the frequency of marijuana use, and the potency (strength) of the strain of cannabis used. This article will attempt to explain the process which occurs when marijuana is introduced into your system; and how it is ultimately broken down and purged from your system, and answer: How Long Does Marijuana Stay in Your System?

THC/Marijuana is similar to all drug substances in regard that all drugs must be digested, broken down, and then flushed from the system. Marijuana is most commonly ingested by smoking; however there are other ways to introduce it into your system. Once in the system, your body will begin to break it down THC through the metabolic process. The human metabolism is a series of processes which processes all substances introduced into our system to convert those substances into energy and waste.

The active chemical found in marijuana is called THC or Tetrahydrocannabinol. THC is primarily metabolized by the liver before being excreted through the kidneys, and then flushed via feces and urine.

The remaining THC metabolites not easily pass through our body's excretion process ultimately end up stored in our bodies fat cells. THC is not broken down easily or quickly by the human system, so it remains in our body's fat cells much longer than other drug metabolites

A person's body mass index (BMI) or body fat percentage is a key factor when figuring out how long marijuana stays in our system. The higher the BMI the longer the system will take to excrete marijuana from the system.

It has been proven that in most cases frequent marijuana users, evidence of THC may be detected via urine drug testing for up to 30 days.

A casual marijuana (weed) user (1-2 times a week) may expect marijuana to remain detectable for 7-10 days.

Chronic marijuana users (everyday) can expect THC to remain detectable in their system for 30-90+ days.

Detecting marijuana in hair is another story. Frequent marijuana use will remain detectable in a hair drug test after 48 hours of use and until the contaminated hair is removed from the body.