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How Long Does “Meth” Stay In Your System? (Methamphetamine)

Methamphetamine (MAMP), commonly referred to as “meth,” is an illicit Schedule II controlled-substance in the United States.  It is often used recreationally for a variety of reasons such as to: attain a temporary state of euphoria, enhance sexual experiences, promote wakefulness, boost motivation, and/or bolster cognitive function.  The pleasurable experience associated with methamphetamine usage is derived primarily from increases in dopamine concentrations [within the brain].

Though dopamine increases stemming from methamphetamine usage may yield favorable effects (e.g. euphoria), sometimes dopamine levels increase too much; resulting in unwanted effects.  Excessive or high dopamine levels caused by methamphetamine ingestion may provoke: agitation, anxiety, delusions, hallucinations, mood swings, and violence.  Abuse of methamphetamine may even trigger a condition known as “stimulant psychosis” in which a user has a psychotic break.

Scientific research reveals that methamphetamine is a potent neurotoxin, capable of killing brain cells (specifically dopamine neurons) and damaging various structures within the brain.  Despite knowing the deleterious effects of methamphetamine ingestion, many people are unable to stop using because they are addicted; after all, it is one of the most addictive drugs on the planet.  That said, when push comes to shove and meth addicts want to turn their lives around, it is possible to start fresh and fully clear meth from their systems.

How long does “meth” stay in your system? (Methamphetamine)

Assuming you’ve stopped using meth and have dealt with the array of unpleasant meth withdrawal symptoms, you may want to know how long meth stays in your system.  Knowing how long the drug (and its metabolites) remain in your system is valuable information that may help you understand your likelihood of passing a drug test.  Passing a meth drug test may be necessary to get a new job, maintain your current job, or prove that you’ve been able to stay sober in rehab.

It is documented that the elimination half life of methamphetamine spans between 10 and 12 hours.  This means that it could take up to 12 hours for 50% of the drug to get eliminated from your system.  When considering the elimination half life, it becomes apparent that methamphetamine may be detectable within your system for up to 2.75 days (following your most recent ingestion).

It would be most likely to stay in your system for a longer term if you used intravenous methamphetamine due to the fact that the half life is ~11.4 hours for IV, compared to intranasal or smoking methods of ingestion with half lives of ~10.7 hours.  Therefore if you smoked methamphetamine, it is likely that it would be eliminated from your system in 2.45 days; quicker than an intravenous user.

Regardless of the dosage or modality by which you administered methamphetamine, it is recommended to cease usage as soon as possible if you want it to fully clear from your system.  It is also important to understand that specific rates of clearance are subject to individual variation based on personal factors such as: age, frequency of usage, metabolism, liver/kidney functionality, etc.

Factors that may influence how long meth stays in your system

If considering specific rates of methamphetamine clearance, there is some variation among users.  This variation in clearance speed is largely due to individual factors, but could also be related to the route by which methamphetamine is administered.  Some speculate that frequency of usage and dosage last utilized may also impact how quickly meth is cleared from the body.

  1. Individual factors

Perhaps the most influential factors in regards to clearance speed of methamphetamine are a person’s age, genetics, metabolism, level of physical activity, and whether they take any other drugs (or supplements).  A younger individual who exercises regularly and has a fast metabolism may clear meth quicker than an elderly individual with liver problems.

  • Age: A person’s age is understood to affect bodily processes, including metabolism and the ability to clear toxins. Methamphetamine is an exogenous substance and will be perceived as a toxin by your body.  Younger individuals are thought to have more efficient functioning of liver and kidneys, and typically maintain higher metabolisms than older individuals.  As a result, it should be expected that younger people will metabolize and clear meth at a quicker rate than elderly (age 65+).
  • Genetics: It should be suspected that certain genes may aid in the metabolism of methamphetamine. While specific genes associated with expedited or efficient metabolism of methampehtamine haven’t been pinpointed, many genes facilitate increased efficiency in metabolizing various drugs.  A person with genes that efficiently metabolize methamphetamine may clear it from their system quicker than inefficient metabolizers.
  • Liver/kidney function: A person in good physical health will generally have a properly functioning liver and kidneys, resulting in normal metabolism of methamphetamine. Since meth is metabolized primarily in the liver, and broken down by various enzymes, a person with renal abnormalities may retain the drug for longer than average.
  • Metabolism: It is also necessary to account for individual metabolism when considering variation in methamphetamine clearance. Individuals with a fast baseline metabolism may clear the drug from their system quicker than a person with a slower baseline metabolism.  A multitude of complex factors such as: age, body mass index, dietary intake, activity level, etc. – can contribute to metabolism.
  • Other drugs / supplements: If you’re taking any other drugs and/or supplements along with methamphetamine, it is important to consider how they may interact. Co-administration of certain drugs may prolong the clearance of methamphetamine from your body (e.g. 2D6 enzyme inhibitors), whereas others may actually speed up clearance.  Similar variability in clearance rates may occur as a result of ingesting dietary supplements.
  1. Route of Administration

There is substantial evidence to suggest that the route by which you administer meth will affect the rate at which your body is able to clear it.  Specifically, those who inject it intravenously tend to have slightly longer clearance rates than those who resort to intranasal (snorting) or smoking.  The time it takes to fully clear intravenously injected meth from your system may be hours longer than it would take to clear smoked or snorted meth.

Intravenous (IV): The elimination half life of intravenously injected methamphetamine is reportedly 11.4 hours.  This means that following cessation of usage, it takes your body 11.4 hours to clear 50% of the drug.  If we were to do the math, this means that in order to assure that 100% of the drug is cleared from your system, it could take up to 2.61 days (nearly 63 hours).

Smoking: The elimination half life for smoking methamphetamine is documented as 10.7 hours. In other words, following cessation of usage, a smoker of meth would clear 50% of the ingested drug in under 11 hours.  The clearance rate would be quicker than an intravenous user, but still could take up to 2.45 days (nearly 59 hours) to fully clear it from the body.

Intranasal: The clearance rate of methamphetamine from the body of those who snort it is approximately equal to those who smoke the drug.  Therefore it takes nearly 11 hours to clear 50% of the drug from the body, and up to 2.52 days to fully clear 100% of the drug from the body.  Specifically, it could take slightly over 60 hours for systemic clearance of meth among intranasal users.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/14586388
  1. Frequency of usage

How often you use methamphetamine (and the time span over which you use it) may influence the rate at which your body is able to clear it.  The more frequently a person uses the drug, the greater their level of tolerance, and ultimately the higher the dose they are likely ingesting. In addition, the more times a person ingests meth throughout the day, the greater the total accumulation of the drug within their system.

With ongoing frequent usage of methamphetamine, a person’s system may adapt and be unable to process or excrete the drug as quickly as an infrequent user.  This could be due to neurophysiological adaptations caused by the drug, but may also be related to the fact that they are ingesting dosages that exceed their body’s clearance mechanisms.  Therefore, one could conclude that long-term heavy users will retain methamphetamine for a longer term than short-term, infrequent users.

  1. Dosage

Some studies suggest that there is unlikely to be a relationship between dosage of methamphetamine and excretion rate.  However, a common belief among users is that ingestion of high meth doses will result in greater accumulation of the drug throughout the body.  With greater accumulation of the drug, one can logically expect a prolonged clearance period.

If there is a relationship between dosage and the duration over which methamphetamine stays in your system, high-dose users will eliminate the drug at a slower rate than low-dose users.  Assuming the dose theory in regards to elimination has merit, it is unknown as to how much quicker 10 mg would be metabolized and excreted compared to 200 mg.  There is likely a threshold speed at which the body is capable of metabolizing methamphetamine.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/15570192

Methamphetamine Peak Levels, Metabolism, & Excretion

Following oral ingestion of methamphetamine, the plasma concentrations of the drug reach a peak between 2 to 4 hours.  Those who administer methamphetamine intravenously reach peak blood levels within just moments following injection, and several minutes after smoking.  When used for therapeutic purposes, blood concentrations of methamphetamine typically range between 0.02-0.05 mg/L.

When administered recreationally for a “high,” blood concentrations usually fall within the range of 0.01 to 2.5 mg/L (~0.6 mg/L), but when abused these levels exceed 2.5 mg/L.  The body metabolizes methamphetamine primarily via cytochrome P450 2D6 (CYP2D6).  CYP2D6 is an enzyme expressed primarily in the liver that breaks down methamphetamine into amphetamine (the active metabolite).

Plasma concentrations of the “amphetamine” metabolite tend to peak at around 10 hours post-methamphetamine administration.  Methamphetamine is also broken down into various inactive metabolites including: p-OH-amphetamine and norephedrine.  The metabolites associated with methamphetamine usage can be detected in a person’s system for up to 6 days, but are generally eliminated within 3 days.

It is thought that between 30% and 50% of orally-ingested methamphetamine remains chemically unchanged upon urinary excretion.  Among intravenous users, it is thought that up to 45% of methamphetamine remains unchanged upon urinary excretion.  Typically between 7% and 23% will be excreted in the form of amphetamine (the active metabolite).

  • Source: http://www.nhtsa.gov/people/injury/research/job185drugs/methamphetamine.htm

Types of Meth Drug Tests (Methamphetamine)

There are several ways in which a person can be tested for methamphetamine.  The most common type of test issued is a urine test.  Blood testing is also fairly common, but less preferred due to the fact that it is more invasive than urine testing.  Other types of testing for meth include: hair testing (which works great to detect usage over a long-term) and saliva testing (which is less invasive than other methods).

Urine tests: Collecting and analyzing fresh urine samples is among the most common ways to test for the presence of methamphetamine (and its metabolites).  Urine tests can determine whether someone has used methamphetamine within an approximate period of 1 to 5 days; the drug is excreted in urine within 2 to 5 hours of ingestion.  For most individuals, methamphetamine is unlikely to show up in urine for longer than 3 days.

However, among chronic long-term users – it may appear within the urine for up to 6 days.  It should be noted that urinary pH (acidity vs. alkalinity) can affect results.  Since nearly 50% of methamphetamine remains unchanged prior to urinary excretion, it is easily detectable.  Furthermore, nearly 10% to 20% of the amphetamine (AMP) metabolite will appear in the urine.

Blood tests: Depending on route of administration, meth can remain in the blood for a period of 1 to 3 days following ingestion.  A blood test should detect the presence of methamphetamine within 2 to 4 hours of oral ingestion, several minutes after smoking, and just moments after intravenous injection.  Since blood testing doesn’t detect methamphetamine for as long as a urine test, and is more invasive, it isn’t used as often.

Hair tests: While a hair test may not tell us whether a person used meth recently, it can tell us whether an individual has used meth within the past 90 days (3 months).  Hair testing typically involves collecting a 3 cm to 6 cm sample of hair, and then analyzing the hair to determine whether the drug is present.  Since hair grows at a rate of 1 cm per month, if a person recently used meth for the first time, an immediate hair test wouldn’t show a positive result.

However, if a person used meth today and was hair-tested in 2 months, the test should come back positive.  The hair test is considered a highly-accurate form of testing.  If conducted by a laboratory with a long (cm) sample of hair, results may accurately detect meth usage over a term longer than 90 days.

Saliva tests: Saliva testing to detect the presence of methamphetamine is rare compared to other testing modalities.  That said, a swab of saliva may be collected to accurately determine whether an individual had ingested meth within a 1 to 3 day period.  Meth can be detected in saliva in as little as 10 minutes post-ingestion, and usually remains for a period of 48 hours (2 days).

  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2709797/
  • Source: http://www.clinchem.org/content/48/10/1703.full

Why are people tested for methamphetamine?

There are a multitude of reasons why a person would be tested for methamphetamine.  In the world of athletics, using a psychostimulant is regarded as “doping.”  Additionally, some employers and/or rehabilitation facilities may require that individuals be tested for the presence of meth.

  • Athletic doping: In certain professional sports such as football, boxing, and even racecar driving – everyone is looking for an edge. Methamphetamine gives users increased energy, improves their focus, and enhances alertness.  In many sports, athletes are tested randomly to ensure that they haven’t been using methamphetamine (or any other substances).
  • Employers: Many employers want to make sure that their employees aren’t ingesting illicit substances. Since up to 50% of meth is metabolized unchanged as “methamphetamine,” it would be relatively easy to detect those who are using illicit drugs.  Someone testing positive for methamphetamine (specifically) could be fired from their job.
  • Drug-free commitment: Many former users of meth assure others that they are no longer using the drug. In order to hold them accountable, family members and friends mandate that the person agrees to random drug testing.  Random testing helps them stay focused on remaining drug-free and sober from meth.
  • Rehab programs: Some rehabilitation programs will test clients to determine whether they’ve been staying “clean” for a period of time. Rehab clinics typically utilize urine testing, but may also call for hair testing to get a more accurate long-term understanding of a person’s usage.

Tips to clear meth from your system quickly

Below is a short list of tips that may help you clear meth from your system quickly.  Many of these are common sense.

  1. Stop using meth immediately: The quickest way to clear meth from your system is to discontinue immediately. The quicker you stop using the drug, the faster your body will excrete it.  If you continue to use, the drug will accumulate – resulting in a prolonged clearance period.
  2. Stay hydrated: It is important to stay hydrated to flush methamphetamine from your system. If you are dehydrated, the drug may not be metabolized and excreted via urine as quickly as it could be. Drinking sufficient water should help you eliminate meth at a normative rate.
  3. Manipulating pH: Those that have a more acidic pH can eliminate methamphetamine at a quicker rate than those with an alkaline pH. It is known that acidic urine expedites excretion of meth, whereas basic urine prolongs excretion.  Eating certain foods to increase your acidity may help clear methamphetamine at a more rapid pace.
  4. Exercise: It is known that exercise promotes a quicker metabolism and healthy organ function. Those who exercise frequently may be able to speed up their metabolism and increase the efficiency by which their body is able to clear meth.  If you aren’t already exercising, adding a run or jog to your routine may help.
  5. Healthy diet: A proper diet ensures that your body is getting the nutrients necessary to function optimally. Those with dietary deficiencies may clear meth at a less efficient rate than those who are eating healthy foods such as vegetables, fruits, and foods with high fiber.

Have you been drug tested for methamphetamine?

If you’ve been subject to drug testing for methamphetamine, mention whether you passed or failed the test.  To help others better understand your situation, note how long you had stopped using meth prior to your drug test, as well as the specific type of test that was administered (e.g. urine, hair, blood, etc.).  Also discuss your route of meth ingestion, frequency of usage, and the dosage that you typically consumed.

For those that passed the drug test, were there any tricks or tips that helped you clear meth from your system quicker?  Share any helpful detoxification methods and/or techniques that you believe may have helped expedite the metabolism and excretion of methamphetamine from your system.

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{ 21 comments… add one }
  • Rabbitt December 11, 2015, 7:28 am

    I quit for 5 days I was using between a quarter and a half a gram a day for about 2 months and I failed. The test I took was a urine test and the dr. said that I failed for meth and I told her I didn’t remember doing any. She said well you would remember if you put a meth pipe up to your mouth and smoked it. So I said yes, I’m sure I would, but my question is, can they tell if you were smoking it or snorting it or if you were handling the stuff and it somehow got contaminated? It there is no way to tell that? Why would she assume I smoked it? Anyway, any answers would be greatly appreciated. Thanks.

    • David January 22, 2016, 6:14 am

      I can see the frustration of being singled out as a smoker. But does it really matter? You tested dirty, you know when you used last. And trying to lie your way out of testing dirty by playing stupid, is just as bad. But no they can’t tell from any test if your a smoker, sniffer and/or a slammer. Well a slammer will have tracks, a sniffers nose will be raw or may bleed for no apparent reason and a smoker… I don’t know how to spot out a smoker. Bottom line… A tweaker is a tweaker. There is no getting around it.

  • Zoie December 20, 2015, 10:13 am

    I think her comment about smoke just comes from the general assumption that it’s how the drug is used lol. I have plenty of non-user friends who are surprised when I say I snort it. As to why you could have failed is just math. You may have quit 5 days ago BUT you liver didn’t start at zero, the last time you used. Had you used once, then prolly woulda been good, but if you’re using a 1/2g one day and following it up with 1/4g the very next day…

    Your liver was still holding onto what it hadn’t processed the day before. Now multiply that by however many days you used outta those 2 months. Even if you took into account the days you didn’t use, it still had accumulated an undesirable amount to process…even if your liver was at 100%… Your still in the “heavy user” range and would need the farther end of 3-10 days.

  • Amber March 15, 2016, 10:48 pm

    I stopped using Meth for 7 days and had to take a urine test for probation. I used 3 ready clean drinks, ate fruits and veggies and drank 5 gallons of water in 1 & 1/2 days and I still failed my drop. It had been considered an amphetamine, but still Meth substance. I say water, exercise, anything fiber and peeing are the best way to go.

  • nick March 20, 2016, 4:03 pm

    I had injected about a half a gram of meth one Thursday night and had a drug test the next Thursday. I had went into the hospital and detoxed off of everything the night I used it and a week later I still showed positive for meth. I am in stage 3 cirrohosis and I guess my liver being bad is why it was still in me.

  • Calligraphy March 21, 2016, 7:16 am

    While your ph is acidic your renal gland is pushing more out. You need to take white vinegar to become acidic then drink water to push it which will slowly neutralize your pH. So you must continue to drink white vinegar. Then before your test you need to become alkaline so your renal gland suppresses excretion.

    Drink baking soda, it will give you the runs. The balance comes from staying alkaline long enough to pee the acid dirty waste out until your bladder is full of more basic urine. The baking soda will try to dehydrate you and you must hold just enough long enough to pee with color. This is a 2-3 hour process to clear your bladder at a minimum. It’s not pleasant.

    Do this over the course of several UA’s and you’ll want to quit to avoid doing this process. I would by an at home test and check right before going in. One time test still showed dirty, a pee later went in and barely passed. I can say that I’ve had much misfortune during this process and recommend just quitting to avoid going through this.

  • Peebody April 23, 2016, 4:59 pm

    I went over a year clean and sober from every substance including alcohol, but on a Friday I took 3 hits off of a pipe and exactly 3 weeks to the day on a Friday – I was tested by my probation officer. It was a urine test and I failed the test for methamphetamine? How does that happen? Three hits and 21 days later and I was still dirty. Anybody out there have any clues as to why?

  • Dee May 29, 2016, 3:46 am

    I’m hoping my hair test will show negative. I have used meth a handful of times though the years but have not done but approximately smoked one half of a quarter. That’s been a week ago and this coming Tuesday is court. Test will probably happen. I’m scared this one time may come back to haunt me. I have long hair, I’m female weigh about 150 lbs. Any Advice??? Please and thanks. I have learned my lesson.

    • Danielle June 20, 2016, 6:42 pm

      Cut your hair short and bleach it.

  • Jlm June 24, 2016, 11:04 am

    I have a question… I smoked meth for the first time yesterday and I have court on Tuesday. Will it still show up on a drug test?

    • Worried June 26, 2016, 11:31 am

      I smoked Meth on Sunday at 3am for the first time and I go to the doctor on Thursday at 9 am for a urine test. Any suggestions to pass?

      • Aaron Shelton August 7, 2016, 2:06 am

        Go buy herbal life from GNC and do as it says and you will pass with flying colors.

        • Ginger August 24, 2016, 5:41 pm

          Herbalife shake or is there some kind of cleansing drink? Keep searching but can’t seem to find it on GNC site…

  • Tammy July 7, 2016, 11:37 am

    I quit doing meth for 7 days, and I caved last night. I really need to find out how to get this out of my system in 6 days. I am 45 years old, I weigh 180lb. Please help me out with the best suggestion that will positively work.

  • Chris July 26, 2016, 1:51 pm

    I use about a 10 or 20 once every two to three weeks and pass a urine test in about 60 hours…

  • Scared July 28, 2016, 10:41 pm

    I have injected meth once in my life. I am 20 years old 180 pounds and am 6 foot 1. I injected under a tenth of a gram of meth and drink around 6 gallons of water a day. What is an estimated amount of time that the meth will be in my system? I AM VERY WORRIED I HAVE A BIG INTERVIEW COMING. SOMEONE PLEASE ANSWER ME AS SOON AS POSSIBLE. THANK YOU.

    • Aaron Shelton August 7, 2016, 2:07 am

      Buy herbal life fom GNC and follow directions.

  • Coy August 2, 2016, 12:34 pm

    I snorted a half a gram a day for about 6 months. I had a hair test for a custody hearing so I did the bleach and dye method. Bleached my hair 2 times the day before the test dyed it back to normal color then soaked in vinegar and washed with tide. Failed the test. The hair test can’t be beat. I don’t care what you read on the internet.

  • Opi August 9, 2016, 7:18 pm

    Great article however there’s something you forgot to mention that is especially important in blood serum half-life: the differing bioavailability of methamphetamines relevant to their route of administration.

    -Insufflated (snorted) meth results in 79% of the dose actually having a CNS effect.

    -Smoked (vaporized is a more accurate term, as the meth does not combust and therefore does not produce smoke) methamphetamine has a range of bioavailability as some of the meth is destroyed during heating (caramelization, or brown coloration of melted crystalline methamphetamine) and some is also exhaled. The bioavailability of this route varies from 40% to around 70%.

    -IV methamphetamine usage has a bioavailability of 100% – meaning 100% of the dose is absorbed as IV use doesn’t undergo any form of first-pass metabolism and the entire dose can be delivered assuredly without chemical decomposition.

    Thus, the half-life times are skewed by the AMOUNT of methamphetamine in the system. Say a person were to use 50mg insufflated, 50mg smoked, and 50mg IV. The actual effective dose for the snorting user would be 40mg and the elimination half-life would act on that number. The actual effective dose for the smoker could be anywhere from 20mg to 35mg, maybe a bit more – and the elimination rate would act on that particular dose level.

    An IV use of 50mg would result in all 50mg being absorbed, and the elimination half-life would work on that particular dose level. This is why users who inject their methamphetamine take longer to clear their system – the rate of clearance is the same, but the total amount that must be cleared is unchanged by first-pass metabolism and thus it will take longer to fall before positive test cutoff concentrations.

    I would also like to add that it is possible to speed up methamphetamine’s rate of elimination through the use of CYP2D6 inducers. CYP2D6 is the liver cytochrome responsible for breaking down and eliminating methamphetamine and by taking an inducer – a medicine that increases the efficacy and rate of this particular part of your liver – you can really cut down on the amount of time meth remains detectable above cutoff rates in your blood serum. Two easily obtained and generally safe ways of going about this are the common OTC nasal spray Rhinocort, and the common OTC herbal supplement St. John’s Wort.

    As with any new medications, even over the counter, consult with the pharmacist on staff at the place you purchase these about possible interactions with any medications you may be taking. Ultimately though, your main goal should be to get clean off methamphetamine. I won’t preach at you for paragraphs about this, because you already know it’s terrible for you. Getting clean will be hard – one of the most difficult things you’ll ever experience – but it’s certainly possible with the right help and it is -so- worth it (I am a former IV heroin user with 3 years 9 months clean from H).

    Don’t get trapped by an individual program’s claims that only their ways work. If a religious group doesn’t help you, switch to a 12 step group. If that doesn’t help you, switch to a therapist. If that doesn’t help you, try alternative medicine. If that doesn’t help, try medical detox. If that doesn’t work, try marijuana maintenance (believe it or not, this has been a huge help to me in staying away from heroin) etc, etc, etc. There are many ways to get clean and I wish you the best, and that you can resolve your meth addiction and experience the beauty of a free life, you deserve better.

  • scared September 10, 2016, 10:05 pm

    I did two small shots Thursday night and have a drug test next Thursday seven days away. Does anybody think I’ll pass? Please give your opinion.

  • I'm so stupid October 18, 2016, 9:09 pm

    I used for a week probably total amount 2 grams and I still tested positive 8 days later. Lost my pain doctor because of it. 1 time and you’re OUT. I am 58.

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