How Long Does Methamphetamine (Meth) Stay in Your System?

Methamphetamine in Your Blood, Urine, Hair, & Saliva

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Methamphetamine is a stimulant drug that speeds up the body’s systems. After marijuana, meth is the second most popular illicit drug in the world.

Also referred to as meth, crystal, speed, or crank, methamphetamine is classified as a Schedule II drug in the United States. This means that it has a high potential for abuse which may lead to severe psychological or physical dependence.

Though most often used illicitly as a recreational drug, it is also available in prescription form as Desoxyn, which is used for treating ADHD and the short-term treatment of obesity.

How long meth stays in your system and how long it can be detected in a drug test depends on several factors, including the amount of meth used and frequency of use. It also depends on the type of drug test being used. Though some tests only detect meth for up to three days, others can detect it for up to three months.

How long meth stays in your system
Verywell / Jessica Olah

How Long Does It Take to Feel Effects?

How quickly you feel the effect of meth depends on the form, how it's administered, and how much of it you use. Smoking or injecting delivers meth to the brain quickly (within seconds), causing an immediate "rush." When taken orally, meth starts producing effects within 15 to 20 minutes.

The initial effects of meth are often described as euphoric. Additional effects are similar to those of other stimulants and include:

  • Decreased appetite
  • Hyperthermia (higher than normal body temperature)
  • Increased attention
  • Low inhibitions
  • Physical alertness
  • Reduced fatigue

Meth gives you the energy to get a lot of things done in a short amount of time. The downside is that after a few hours, the crash can leave you feeling drained and depressed.

Driving Concerns

According to the National Highway Traffic Safety Administration (NHTSA), drivers who are under the influence of methamphetamine display a wide variety of behaviors including:

  • Accidents
  • Agitation
  • Awkward movements
  • Disorientation
  • Erratic driving
  • Irrational or violent behavior, and unconsciousness
  • Lane travel
  • Nervousness
  • Rapid and non-stop speech
  • Speeding
  • Staggering
  • Unintelligible speech

In the 101 cases reviewed by NHTSA in which meth was the only drug detected, impairment was attributed to "distraction, disorientation, motor excitation, hyperactive reflexes, general cognitive impairment, or withdrawal, fatigue, and hypersomnolence."

Because meth remains in the system long after the effects of the drug wear off, you might feel like you are OK to drive. But you can be charged with driving under the influence if any amount meth shows up in a blood or urine test.

Meth and Alcohol

Some believe that methamphetamine can reverse some of the impairment effects of alcohol. That's because meth may restore alcohol-induced impairment in simple repetitive tasks of short duration. However, NHTSA research has uncovered no restoration of alcohol-induced deficits of balance and steadiness.

Overall, research indicates that methamphetamine is more likely to increase the impairing effects of alcohol. The substances should not be used together.

The combination can also increase the risk of alcohol poisoning since people do not realize how much they’ve had to drink.

How Long Does Methamphetamine Last?

The half-life of methamphetamine is an average of 10 hours. This means it takes about 10 hours for half of the ingested dose to be metabolized and eliminated from the bloodstream. 

When taken orally, concentrations of methamphetamine peak in the bloodstream between 2.6 and 3.6 hours, and the amphetamine metabolite peaks at 12 hours. If meth is taken intravenously, the elimination half-life is a little longer at about 12.2 hours.

Methamphetamine is metabolized by a liver enzyme and is excreted by the kidneys in urine. It is metabolized (or broken down) into amphetamine, and 4-hydromethamphetamine.

Compared to other drugs, the effects of meth are relatively long-lasting. The "feel good" feeling typically lasts for six to 12 hours, but can sometimes last up to 24 hours.

After taking meth, most people experience the following stages of meth intoxication before crashing:

  • The Rush: This stage occurs after your first ingest meth. It usually ends in five minutes, but it can last up to 30 minutes. 
  • The High: The initial rush is followed by a longer meth high. Sometimes called "the shoulder," the high typically lasts four to 16 hours.
  • The Binge: During the binge phase, people may try to maintain their high by smoking or injecting more meth. A binge can last from three to 15 days. During this time, they may barely eat or sleep. 
  • Tweaking: After prolonged use, meth is no longer able to give you a high, and you begin "tweaking," which is a stage characterized by symptoms like paranoia. This period can last up to two weeks.

Detection Time

While a meth high lasts less than a day, the drug stays in your system for much longer. How long meth can be detected in your system depends on a variety of factors, including how much and how often you use meth.

The more meth you use, the longer it takes to clear your system.

The type of drug test used to detect meth also makes a difference. When it comes to detecting meth, different tests have different meth detection time ranges.

  • Urine: Meth can be detected in urine two to five hours after use and up to seven days following the last dose.
  • Blood: Meth can be detected by a blood test within one to two hours after use and up to three days following the last dose.
  • Saliva: Meth can be detected in saliva 10 minutes after use and up to four days following the last dose.
  • Hair: A hair follicle test can detect meth use in the past 90 days.

False Positive Testing

Urine tests are the most common method of drug testing, and immunoassays are the most commonly used urine drug testing approach. Immunoassays are a quick and inexpensive drug screening tool.

But the immunoassay has a major drawback. They will detect substances with similar characteristics, resulting in a false-positive result. This means it's possible to test positive for methamphetamines even if you don't use the drug.

A false positive occurs when the test results come back positive for drugs, even though you haven't used drugs.

Taking the following medications can result in a false-positive result for methamphetamine:

  • Antibiotics, such as Levaquin (levofloxacin) and Cipro (ciprofloxacin)
  • Antidepressants, such as Wellbutrin (bupropion), Prozac (fluoxetine), Zoloft (sertraline), Effexor XR (venlafaxine), and trazodone
  • Antipsychotics, such as Thorazine (chlorpromazine)
  • Blood pressure control medicine, such as Trandate (labetalol)
  • Central nervous system stimulants, such as Ritalin (methylphenidate) and Adderall (dextroamphetamine-amphetamine)
  • Decongestants, such as Sudafed (pseudoephedrine)
  • Oral diabetes medicine, such as Glucophage (metformin)

Because of the risk of false-positive results, testing to identify specific drugs, rather than classes of drugs, is needed to confirm a positive urine drug screen for methamphetamine. To ensure clinicians can accurately interpret your drug screen results, always disclose any prescription or over-the-counter medications you are taking.

Factors That Affect Detection Time

The timetable for detecting methamphetamine in the human body depends on the individual's health, metabolism, age, physical activity, and frequency of use, making it difficult to determine how long meth will show up on a drug test.

  • Overall health: Your overall health, including liver and kidney function, can play a role in how quickly meth is processed and cleared from your body.
  • Frequency of use: People who use amphetamine very frequently will have longer detection times than those who use the drug one time.
  • Metabolic rate: People with a high metabolism tend to process and excrete amphetamine more quickly than those with a slower metabolism. Age, activity level, and overall health can all play a role in your metabolic rate.
  • Smoking vs. injecting: Whether you take the drug orally or intravenously can impact detection time. If you take it orally, it will be eliminated slightly more rapidly than if you inject the drug. If, on the other hand, you've been prescribed Adderall and take it as prescribed, the drug will likely remain in your bloodstream for longer periods of time.

How to Get Methamphetamine Out of Your System

There are plenty of false claims and myths when it comes to how to pass a drug test.

For example, there are false claims that "baking soda bombs," which is a mixture of water, bleach, and baking soda, mask the presence of methamphetamine in urine. There is no proven research that this works, and further, you take an enormous health risk when you ingest any amount of bleach.

The only way to get meth out of your system is to stop using the drug and allowing your body time to metabolize and eliminate it. Staying healthy by getting regular exercise and drinking plenty of water may also help you metabolize the substance more quickly.

Symptoms of Overdose

One of the main reasons to be aware of how long meth remains in the system is the risk of overdose. Here are some symptoms of a meth overdose:

  • Chest pain
  • Difficulty breathing
  • Extremely high body temperature
  • Heart attack
  • Irregular heartbeat
  • Kidney damage or failure
  • Paranoia
  • Seizures
  • Severe agitation
  • Stroke

Some overdose symptoms can be life-threatening, so it is important to seek professional medical help right away if you suspect that you or a loved one may be experiencing a methamphetamine overdose.

Getting Help

If you're concerned about having too much meth in your system or testing positive for the drug, it's likely time to seek help or consult your doctor. If you use meth heavily and/or regularly, it's best to detox from the drug under the guidance of a medical professional who can guide you safely through the withdrawal and treatment process.

Twenty-four hours after you stop using meth, you can expect to experience symptoms of withdrawal, which can range from mild to severe, depending on the frequency of use and dependency. Some common signs and symptoms of meth withdrawal include:

  • Anxiety
  • Cravings
  • Depression
  • Fatigue and sleepiness
  • Increased appetite

If you or someone you love wants to quit using meth, there are steps you can take to get through the withdrawal process and succeed in your recovery.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. 

For more mental health resources, see our National Helpline Database.

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6 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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