One of the reasons that drug tests are a colossal scam is that not all drugs stay in your system for the same amount of time. In fact, some of the least dangerous drugs such as marijuana can be detected in your urine, blood, and hair for much longer than harder drugs such as heroin and meth — meaning that schools, employers, and law enforcement agencies that drug test disproportionately penalize marijuana users.

Attn: has previously reported on how workplace drug testing discriminates against marijuana users, but in order to illustrate just how disparate drug interactions can be, here's a breakdown of how long each drug stays in your system.