Drug tests may be used for pre-employment screening or after an on-the-job injury, in medical settings, in law enforcement, or in addiction treatment to identify drug abuse. These drug tests can detect a wide range of commonly used drugs like heroin, fentanyl, prescription opioids, cocaine, and marijuana, as well as some less common drugs like MDMA, depending on the test.
Some drugs are detectable for months, such as in hair tests, while others may clear from the body within hours or days, depending on the test type and drug properties. The drug, the type of test, and individual factors can influence how long drugs stay in your system.
Key Points
- Drug tests are used by employers, law enforcement, medical professionals, and more to detect the use of prescription and illicit drugs.
- Different drugs stay in the body for different lengths of time, depending on factors like the drug itself, the dosage, and your individual health.
- Urine tests are commonly used because they are inexpensive, deliver fast results, and can detect commonly used drugs, but saliva, hair, or blood tests may be used in different situations.
- If you’re dependent on a drug, quitting cold turkey may lead to withdrawal symptoms, which can be severe in some cases.
What Is a Drug Test?
Drug tests analyze a bodily sample to detect the use of prescription or illicit drugs. Drug tests are commonly used for pre-employment screening if you’re applying for a job, typically as a urine test, but drug tests can use hair, saliva, blood, or sweat – all with different detection windows.
The purpose of a drug test could be to identify the use of illicit substances, such as heroin or meth, or to detect the use of a specific drug like marijuana. Some drug tests screen for a class of drugs or their metabolites, such as benzodiazepines, amphetamines, opioids or opiates, steroids, or barbiturates.[1]
Urine tests are commonly used in the workplace because they are inexpensive and can offer fast turnaround for results, even as little as a few hours after the test. However, other drug tests may be used in different settings for practical reasons or because they have a longer detection window.
Hair drug testing is considered effective and difficult to tamper with, but external contamination or cosmetic treatments like bleaching may affect results. Hair testing also has a long detection window and may be able to detect drug use up to 90 days after the last use.
Drug Effects Duration and Elimination Time
The effects of different drugs can last for different times. Some drugs have intense but short-lived euphoria, such as cocaine and methamphetamine, while a psychedelic like lysergic acid diethylamide (LSD) can have effects that last for up to 12 hours. This is also true of how long a drug stays in the body, even after the effects have worn off.
The detection windows for different types of drug tests are:[2]
- Urine tests: Depending on the drug and other factors, urine can detect drugs in as little as 10 hours to up to a week after last use.
- Saliva tests: Drugs may be detectable in saliva for 1-36 hours for most drugs, but it can vary.
- Blood tests: Alcohol is detectable for 10-12 hours in blood tests, but many drugs are detectable for a few days.
- Hair tests: Hair follicle tests have the longest detection window and can detect drug use for up to 90 days, but results may be influenced by hair growth rate, hair treatments, and individual metabolism.
Factors That Affect Drug Detection Time
Though there are general guidelines, several factors affect how long a drug is detectable in your system, including:
- The type of drug used
- The dosage of the drug
- The drug use frequency
- Your body mass
- Your metabolic rate
- The presence of other drugs
- Your gender
- Your weight
- Your tolerance
What Is a Drug’s Half-Life?
A drug’s half-life, or the elimination half-life, is how long it takes for a drug’s concentration in the body to drop by 50%. Each drug has its half-life and can be affected by several individual factors, but it helps to determine how long the effects will last and how quickly they’re felt.
Generally, drugs with a long half-life stay in the body longer and are detectable for a longer period. For example, benzodiazepines with a long half-life, such as Valium, may be detectable longer overall than a drug with a short half-life, such as Xanax.
Drug Detection Windows for Common Drugs
There are different periods when drugs can be detectable in a drug test:[3]
- Alcohol is detectable for 10-12 hours in urine and up to 24 hours in saliva.
- Amphetamines are detectable for 2-4 days in urine, 1-48 hours in saliva, and up to 90 days in hair.
- Benzodiazepines are detectable for up to 7 days in urine and up to 90 days in hair.
- Barbiturates are detectable for up to 7 days in urine and up to 90 days in hair.
- Cocaine is detectable for 1-8 days in urine, 1-36 hours in saliva, and up to 90 days in hair.
- Marijuana is detectable for 1-30 days in days in urine, up to 24 hours in saliva, and up to 90 days in hair.
- Methamphetamine is detectable for up to 2-5 days in urine, 1-48 hours in saliva, and up to 90 days in hair.
- Heroin is detectable for 2-3 days in urine, 1-36 hours in saliva, and up to 90 days in hair.
- Morphine is detectable for 2-5 days in urine, 1-36 hours in saliva, and up to 90 days in hair.
How to Beat a Drug Test
Suppose you’re concerned about taking a drug test for a job, law enforcement, or other reasons. In that case, it’s best to avoid the temptation to “cheat” the test with over-the-counter “detox” products or home remedies that supposedly flush drugs out of your system.
First, these methods haven’t been proven effective. Likely, the drug test will still detect drug use. Second, these products aren’t necessarily safe. They’re not regulated, so you don’t know what ingredients or additives you’re getting. In some cases, it may even be obvious that you’re trying to beat the test – which looks as bad to the tester as having positive results.
If you want to have a “clean” drug test, stopping drug use is the only way, but how you quit can be risky. In some cases, stopping drug use suddenly can cause serious – sometimes even life-threatening – withdrawal symptoms. For example, alcohol and benzodiazepines have withdrawal symptoms that can be dangerous, such as seizures.[4]
Other drugs may not have life-threatening withdrawal symptoms, but they’re still painful or intense. This can make it difficult to stick it out on your own and may leave you at risk for relapse and a subsequent overdose.
Depending on the drug and severity of dependence, medical detox may be necessary. This setting provides medical supervision, symptom management, and support to prevent complications during withdrawal. The goal is to keep you as safe and comfortable as possible during your withdrawal.
Some drugs can cause physical dependence with regular use, including certain prescription medications, but physical dependence is not the same as addiction. If you are addicted to a substance, however, it’s important to continue with treatment after detox to address the emotional, social, and psychological factors that influence your substance use patterns.
Get Help for Addiction
If you’re using drugs and concerned about a drug test, don’t try to quit cold turkey. Doing so could lead to severe and potentially life-threatening withdrawal symptoms. Seek help from your medical provider or a professional addiction treatment center to address substance abuse and live a healthier life.