“It was the hardest boyfriend I ever had to break up with [referring to crystal methamphetamines]”~ Fergie
Methamphetamine is known as Chalk, Crystal, Glass, Ice, Meth, and Tina. However, meth is the most common name for the drug.
It’s a highly addictive stimulant. Most people use it by swallowing a pill or snorting a powder. However, some also inject a liquid with the dissolved powder. Those that use crystal meth will sometimes smoke it in a pipe.
Since meth is a stimulant, it gives the person using the drug a sudden rush. While many experience positive emotions, others also feel angry, scared, or edgy.1
On average, meth reaches its peak 15 minutes to 3 hours after taking the drug. However, tests can detect the drug for 2-7 days, depending on the dosage and test type.3, 4
How Long Is Meth Detectable in Drug Tests?
Meth’s half-life is 6-15 hours after someone takes the drug. This is when the body eliminates half of the drug’s active ingredient.2
The rate at which your body eliminates meth depends on your health, build, and dosage. For example, someone with healthy kidneys who drinks plenty of fluids will eliminate meth from their systems much faster than someone with a slower metabolism and poor kidney functions.
In addition, taking meth orally tends to move through your system faster than injecting meth since injecting puts more drugs into your bloodstream, where it may last longer.
Lastly, someone who uses meth continually for several days will see it show up on tests longer than someone who used a low dosage once.3
Use this guide to understand how long meth is detectable in each common drug test.
People expel about 70% of meth in their urine within 24 hours.3 However, urine tests will continue showing positives for meth for up to four days after you use the drug.2
If you consistently use the drug for several days, tests might be able to detect it in your urine for up to a week afterward.3
Meth’s half-life in the bloodstream is 10 hours after someone uses the drug. Tests can detect meth in the bloodstream for 36-48 hours after someone stops using it.3
Saliva tests can only tell if someone used meth recently, as the typical detection window is 24 hours after a single dose. However, some saliva tests can detect meth for up to three days, especially if you frequently use high doses.3
Hair Follicle Testing
Drug tests can detect meth in hair follicles much longer than other tests. The exact time for hair follicles to test negative depends on how much meth you use.
For the average person who uses meth, tests detect the drug up to 90 days after the person stops using it. However, nearly everyone will test negative by 153 days after using meth last, even those that frequently use meth.4
If you are concerned about your use of meth, California Behavioral Health can help you find long-term recovery. Call 855-404-2172 to speak with a treatment support specialist and discuss your substance use disorder treatment options.
Can Other Substances Cause a False Positive for Meth?
Several substances can cause a false positive for meth as it metabolizes into an amphetamine. Doctors commonly prescribe amphetamines as medications. Amphetamines are common in attention deficit hyperactivity disorder (ADHD) medications.5
Some bath salts can also cause a false positive, but this is less common because your body does not absorb enough bath salts to show up in tests as false positives.
Additionally, breathing in secondhand smoke can cause a false positive on drug tests, even though you may not feel the effects of the drug.6
Some chemicals, commonly found in ADHD medications, that can cause a false positive include:5
Before taking a drug test, check your medication ingredients. Then, let the person administering the test know your prescriptions so they can account for potential false positives.
How Long Do the Effects of Meth Last?
People who use meth see results fairly quickly. When someone takes it orally, they usually feel the peak between two and four hours after taking meth. Snorting, smoking, and injecting meth moves the drug to the body’s system much faster, with people experiencing the peak within minutes.2
Here is the average time to reach the peak effect for each method of administration:3
- Injection: Less than 15 minutes
- Smoking: 18 minutes
- Oral: 180 minutes (3 hours)
- Snorting: 15 minutes
Meth’s high fades quickly, which is why people often use repeat doses. This is known as a binge and crash pattern. When this pattern extends over several days, this is a run. People with meth runs also tend to give up eating and sleeping to focus on the drug.6
The use of meth and the rate of fatal overdoses involving meth is significantly increasing. To protect yourself and your loved ones, understand the full short-term and long-term impact of using meth.7
The short-term effects of using meth include:7
- High blood pressure
- Increased body temperature
- Rapid breathing
- Loss of appetite
- Sleep apnea
- Erratic or aggressive behavior
If you continue using meth, you may see some of these negative long-term effects:7
- Heart and brain damage
- High blood pressure
- Heart attacks and strokes
- Liver, kidney, and lung damage
- Paranoia and hallucinations
- Skin problems like itching and sores
- Dental problems
Signs of a Meth Addiction
How do you know if you have a meth substance use disorder?
Use these signs and symptoms to evaluate yourself.
If you answer yes to two or three symptoms, you may have a mild case of substance use disorder. Meeting four or five criteria means you may have moderate substance use disorder. You may have severe substance use disorder if you answer yes to six or more criteria.8
- Taking more meth than you intended
- Feeling the desire to stop using meth but unable to stop
- Spending much of your time buying, using, or recovering from meth
- Craving to use meth
- Unable to complete work, school, or personal obligations because of meth
- Continuing to use meth even though it negatively impacts your social life
- Participating less in social and recreational activities because of using meth
- Using meth even if it is not safe
- Using meth even though you know it will cause physical or mental problems
- Tolerance: Needing to use more meth to experience the same effects
- Feeling withdrawal symptoms when not using meth
Physical tolerance and withdrawal signs also occur when you use prescription medications. In comparison, the other symptoms are exclusive signs of substance use disorder.
Meth Withdrawal Symptoms
If you suddenly stop taking meth after consistently using the drug, you may experience some of the following withdrawal symptoms:6
- Psychosis (disconnection from reality)
- Drug cravings
Help is available no matter how severe your substance use is.
California Behavioral Health is dedicated to helping you find freedom from substance use disorders so that you can live your life to the fullest. If you are concerned for yourself or a loved one, contact one of our treatment support specialists to find the right road to recovery for your situation.
How long does meth stay in your system?
Blood or urine tests can detect meth in your system for 2-7 days after you stop taking the drug. However, hair follicle tests can detect meth up to 153 days after you last used it.
What should you do if you have a positive meth test?
Honesty is the best response to a failed drug test. If you test positive, start by being open about what drugs you currently take. This includes prescription and recreational drugs.
If you had a false positive because of prescription drugs, you could quickly resolve the issue with a note from your doctor. However, if you receive a positive test for drug use, you can ask for help.
Being open and willing to find treatment shows you want to improve. This might encourage your employer to protect your job while you recover.
What is the half-life of meth?
The meth half-life is 6-15 hours after you stop using the drug. This is the time it takes for your body to eliminate half of the drug’s active substance.
What are the effects of meth?
Meth is a stimulant that causes a rush of good feelings. However, some may feel anxious or fearful instead.
Some of the negative effects of meth include high blood pressure, rapid breathing, nausea, and poor sleep.
What do hospitals use meth for?
Healthcare providers use methamphetamines to treat symptoms of attention deficit hyperactivity disorder (ADHD). If you received a prescription, use only the amount your doctor recommended.
If you start feeling any symptoms of dependency or addiction, let your doctor know.
Does meth stimulate the sympathetic nervous system?
Meth activates the sympathetic nervous system. These are the nerves that trigger your fight-or-flight response. When you activate this system, you feel more alert and receive a rush of energy, similar to working out or sensing danger.
Support Is Available
While meth use disorder can feel overwhelming, you do not have to face your fears alone. California Behavioral Health is on your side and wants to see you succeed. We offer various treatment plans that fit your needs and your life.
You can choose from inpatient care, where you receive 24-hour support for faster recovery from more severe substance use disorders. You can also select outpatient care, where you receive treatment while maintaining other obligations like work, school, and family life.
Contact our treatment support specialists to discuss how we can best help you find a better quality of life through substance use recovery.
1. MedlinePlus. (n.a.) Methamphetamine. NIH National Library of Medicine.
2. Richards JR, Laurin EG. (2022 Oct 10). Methamphetamine Toxicity. NIH.
3. Cruickshank, C.C., Dyer, K.R. (2009). A review of the clinical pharmacology of methamphetamine. Addiction, 104, 1085-1099.
4. Suwannachom N, Thanachai T, Junkuy A, O’Brien TE, Sribanditmonkol P. (2015 Sep). Duration of Detection of Methamphetamine in Hair after Abstinence. PubMed.gov
5. Algren DA, Christian MR. (2015 May). Buyer Beware: Pitfalls in Toxicology Laboratory Testing. NIH.
6. NIDA. (2019, May 16). Methamphetamine DrugFacts.
7. Hedegaard, Holly M.D., Minino, Arialdi M., M.P.H., Warner, Margaret, Ph.D. (2020, January). Drug Overdose Deaths in the United States, 1999-2018. CDC. 8. McNeely J, Adam A. (2020 Oct). Substance Use Screening and Risk Assessment in Adults. NIH.