How does smoked crystal meth travel the body? where does it go and how long does it remain?

Smoking meth: Smoked methamphetamine goes into the lungs and into pulmonary vasculature -- and then to the rest of the body including the brain. Effects typically last 2-4 hours, with residual effects up to 12 hours. It can be detectable in the body for 2-4 days after use, depending on frequency of use and other factors. Using at all can be deadly.