By Edmund Murphy

Last updated: 13 March 2024 & medically reviewed by Dr. Kimberly Langdon

Methamphetamine, better known as meth or crystal meth, is a potent illicit central nervous system stimulant that is smoked or injected for its euphoric effects. While the effects of meth are often short-lived, traces of it can linger for much longer in the body's system.

Key takeaways:

  • It can be detected in other forms of standard drug tests, though its detection as amphetamine in urine makes this the most common form of drug test for meth.

  • Most urine tests will detect meth up four days after last use, though it can be detected up to seven days later in heavy users.

  • Many substances have similar detectable characteristics to methamphetamine that can be picked up in a urine test, even if the person being tested has never taken the drug. 

How Long Does Methamphetamine Stay in Your System?

How long does meth stay in your system?

Methamphetamine is metabolized into amphetamine in the body, meaning traces of it will show up in urine up to 5-7 days after it was last taken. It can also be detected in other forms of standard drug tests, though its detection as amphetamine in urine makes this the most common form of drug test for meth. 

These are the average detection times for methamphetamine by test type in the average adult body. 

Type of drug test

Detection time

Urine testing

up to four-seven days

Blood testing

up to three days

Saliva testing

up to four days

Hair testing

up to 90 days

What is the half-life of meth?

Methamphetamine, commonly known as meth, has a half-life of around 10 hours in most people. While meth’s half-life and high may be short-lived, traces of the substance can stay in the system for far longer.[1]

Does meth show up in drug tests?

Different methods of drug testing are able to detect meth over different lengths of time. Some are more accurate than others while some have longer detection windows. 

Meth in saliva tests

Saliva tests are rarely used as substances tend to be hard to trace after a short amount of time. The presence of methamphetamine is detectable 10 mins after last use in saliva and for up to four days.[1]

Meth in hair tests

Hair follicle testing takes longer to process and is more expensive than other drug tests but can trace substance use back much further and more accurately. Meth is detectable in hair follicles up to 90 days after the last dose.[2]

Meth in blood tests

The presence of meth is detectable in blood tests within a few hours of last use and can be traced for up to three days.[3] Cheap or low-cost meth may have fewer meth metabolites in it due to being heavily cut and potentially may not show up in these drug tests.

Meth in urine tests

Most urine tests will detect meth up four days after last use, though it can be detected up to seven days later in heavy users.[2]

Any detectable amount of methamphetamine in the system is a strong sign of meth abuse.

Factors that affect meth detection times

There are many factors that can influence the detection rate of illicit drugs in a toxicology test and these can vary from person to person. 

Factors that influence meth detection rates include:[3]

  • Length of time meth was abused for (a chronic meth user will have larger traces of the drug in their system)

  • Quantity of meth used (the concentration of meth in the system will be higher after a meth binge or heavy meth pipe use)

  • Purity of the drug

  • Fitness (physical activity can speed up the metabolism of meth)

  • Whether other substances were taken (such as alcohol or other stimulants)

  • Weight (obese people will take longer to process meth)

  • Gender

  • Age

  • Pre-existing medical conditions (especially those involving liver, heart, and kidney function)

Related: How long do drugs stay in your system?

Is there a risk of a false-positive drug test result for meth?

Urine tests, or immunoassays, is the most common form of drug testing used in the U.S. as they are cheap, easy to use and provide quick results. 

For meth testing, immunoassays have a drawback that makes them occasionally inefficient. Many substances have similar detectable characteristics to methamphetamine that can be picked up in a urine test, even if the person being tested has never taken the drug. 

This is known as a false-positive result, where the drug has been detected even though it isn’t in the body’s system. Drugs that can have an effect on meth urine tests include:[3]

Antibiotics - Levaquin (levofloxacin) and Cipro (ciprofloxacin)

CNS stimulants - Ritalin (methylphenidate) and Adderall (dextroamphetamine-amphetamine)

Decongestants - Sudafed (pseudoephedrine)

Antipsychotics - Thorazine (chlorpromazine)

Blood pressure control medicine - Trandate (labetalol)

Oral diabetes medicine - Glucophage (metformin)

Antidepressants - Prozac (fluoxetine), Zoloft (sertraline), trazodone

When having a drug test for methamphetamine, it is important to notify the clinician if you have had any of the above substances. This way a more accurate drug test can be conducted.

Related: What does meth look, taste, and smell like?

Can I get meth out of my system quickly?

There are many claims on the internet for quick fixes to get meth out of your system quickly. Not only are these false, but some are also potentially life-threatening. 

A “baking soda bomb” is a concoction of water, baking soda, and bleach that is reported to clear methamphetamine out of the system through urine. This recipe is unproven and incredibly dangerous as consuming bleach can cause liver, kidney, and intestinal damage as well as death.

The only way to get meth out of your system is to let it metabolize naturally and be passed in urine.

Related blog: Can Damaged Skin Heal After Meth Addiction?

Meth addiction treatment

Meth is an incredibly potent stimulant that holds a high potential for abuse, dependence, and addiction. The drug is also cheap and readily available in many areas, making it even more likely for people who try it to become addicted.

If you or someone you care about is abusing meth and may have developed a dependence, it is important to seek out professional treatment before addiction occurs. 

Getting treatment from a rehab facility can help to get meth and other drugs out of your system and regain control of your life. Visit our rehab directory to find a rehab center near you.