How long does meth stay in your system?max?

Which "meth???": Methamphetamine is a short-acting drug, but it has longer acting metabolites which are what are measured in urine. After a single dose, it's half-life is about 4 hours, but metabolites can be found for 2-3 days. After regular heavy use, it can be detected for 5-7 days. Methadone (also called meth) lasts for 3-5 days, and in long-term use metabolites can be detected for weeks.