How long meth stays in the system depends on several factors. 

Ways People Use Meth

The way someone consumes methamphetamine is directly related to how quickly the effects of the drug will be felt. Methamphetamine can be consumed in various ways and it will typically take several days for the drug to completely exit the system. The drug can be smoked, snorted, injected, swallowed, or inserted rectally (known as “boofing” or “booty bumping”).

When methamphetamine is swallowed, the peak concentration is seen within 2-4 hours. When snorted, smoked, or injected, peak concentration will occur within minutes. Smoking, injecting, or inserting methamphetamine rectally allows the drug to reach the brain faster, which causes an immediate and intense “rush”. This is why smoking or injecting methamphetamine has a higher likelihood for addiction. 

Snorting or swallowing produces feelings of euphoria, but not the same “rush” that smoking or injecting does. 

The effects of methamphetamine can last for many hours and it may take up to 4 days for the drug to completely leave the body. Methamphetamine has an average half-life of 10 hours, meaning it takes 10 hours for half the drug to exit the system. Metabolites may show up in drug tests for days after use. Different drug tests have varying detection times. For example, one can receive a positive urine test after a single use for up to 4 days after use, whereas a hair test can be positive up to 3 months later.

Methamphetamine can be used in a “binge and crash” pattern. This means that the pleasurable effects of methamphetamine start to wear off even before the drug has been fully metabolized, so people might try and maintain their high by taking more. A “run” refers to taking the drug over several days and staying awake the whole time,  leading some people to neglect the need to eat, hydrate, rest, or maintain hygiene during that time. 

Combining Substances

People often use methamphetamine with other substances and combining substances can alter the effects of methamphetamine on the body and how someone may feel. People may drink alcohol and take methamphetamine together to “take the edge off” the jitteriness that methamphetamine causes. However, alcohol inhibits methamphetamine metabolism, meaning that it will take longer for methamphetamine to leave the body if someone consumes alcohol.

People may also combine methamphetamine with other stimulants, like cocaine or MDMA. They may take it with opiates like heroin, or with other drugs such as GHB, poppers, or ketamine when engaging in chemsex. Combining methamphetamine with other substances can have unpredictable (and sometimes harmful) effects on the body, and also lengthens the time it takes for all drugs to leave the system.

Differences Between Illicit Meth and Adderall

It should be noted that the effects of illicit methamphetamine can be very different than prescribed methamphetamines or amphetamines, such as Adderall. The effects of Adderall are generally felt within 45 to 60 minutes of swallowing the tablet, and effects do not last longer than 4 to 6 hours. However, effects of illicit methamphetamine can be unpredictable since what is often sold as methamphetamine is of unknown quality and potency and may include other substances or adulterants. 

See the fact sheet for more information and sources.