If you’re wondering “how long do drugs stay in your system?”, the answer isn’t one-size-fits-all. It depends on factors like the type of drug, the dosage, how often it’s used, the kind of test being done, and individual differences in metabolism.
For instance, in a urine drug test, marijuana can be detectable for up to 30 days, while other substances like opiates or benzodiazepines may only show up for 3 to 4 days. With a hair drug test, most drugs can be detected for up to 90 days.
Several factors influence if and when a drug will appear on a test. The type of test being used is usually the biggest factor. Additionally, frequent use can lead to higher concentrations of the drug in your system, making it more likely to be detected.
Here’s an overview of how long common substances can stay in your system:
Substances like LSD, psilocybin mushrooms, synthetic cannabinoids, and MDMA (Ecstasy) typically aren’t detected by standard drug tests.
Here’s how long some common substances can be detected in saliva tests:
Substances such as LSD, psilocybin mushrooms, synthetic cannabinoids, and MDMA (Ecstasy) usually aren’t detected by standard saliva drug tests.
Higher doses of drugs often take longer for the body to process and eliminate. Since the body can only metabolize a certain amount at a time, larger amounts of a substance may remain in your system for an extended period.
Frequent drug use or substance abuse can cause drugs to accumulate in the body, making them take longer to leave your system. This is especially true for marijuana, which can show up in urine tests for up to 30 days in regular users.
Body weight, height, and body fat percentage can all affect how long drugs stay in your system. Since some drugs accumulate in fat cells, people with higher body fat may take longer to eliminate them. Genetics and factors like ethnicity can also influence drug metabolism and detection times.
As we get older, our bodies become less efficient at processing and eliminating drugs. This means medications and substances can stay in an older adult’s system longer than in younger individuals.
The liver and kidneys play a key role in breaking down and removing drugs from the body. If these organs aren’t working properly, substances can stay in your system longer. Age can also affect how efficiently these organs function.
The way a drug is used—whether it’s smoked, snorted, or injected—can influence how long it stays in your system.
Among all the factors, the type of drug and its half-life are the most important in determining how long it will stay in your system.
A drug’s half-life refers to the time it takes for its concentration in the body to decrease by 50%. Using this information, you can estimate how long a drug will remain in the system—after about 4 to 5 half-lives, roughly 94% to 97% of the substance is eliminated.
Drug half-lives are a helpful way to estimate how long a drug stays in your body. However, certain tests—like hair tests—can detect traces of a drug long after 4 to 5 half-lives have passed. Knowing the common half-lives of drugs can give a good indication of how long someone might remain under the influence and when a substance could be detected.
Every drug has a different half-life. Even when you no longer feel its effects, it can still show up on a drug test.
Here are the approximate half-lives of some common drugs:
Heroin: 8 to 22 minutes
Cocaine: 3 hours for oral use
Methamphetamine: 10 hours
Morphine: 2 to 3 hours
Fentanyl: 8 to 10 hours
PCP: 21 Hours
LSD: 2 to 3.5 hours
Diazepam (Valium): 1 to 3 hours
To understand how long drugs stay in your system and when they might appear on different types of drug tests, check out the chart below:
Urine Test: Up to 72 hours
Saliva Test: Up to 24 hours
Hair Test: Up to 90 days
Urine Test: 2-3 days
Saliva: N/A
Hair Test: Up to 90 days
Urine Test: 2-3 Days
Saliva Test: N/A
Hair Test: Up to 90 days
Urine Test: 2-3 days
Saliva Test: 1-36 hours
Hair Test: Up to 90 days
Urine Test: Up to 30 days
Saliva Test: Up to 24 hours
Hair Test: Up to 90 days
Urine Test: 1-3 days
Saliva Test: 1-48 hours
Hair Test: Up to 90 days
While the chart above gives an idea of how long common illicit drugs stay in your system, you might also be curious about the half-lives and detection times of various prescription medications:
A single dose of oxycodone, such as Percocet, can remain in your system for about 3–4 days, with a half-life of roughly 2–5 hours. In urine tests, immediate-release oxycodone is usually detectable for 1–1.5 days, while controlled-release formulations can be detected for 1.5–3 days.
Fentanyl can typically be detected in urine for 2–3 days after use.
Vyvanse, the brand name for lisdexamfetamine dimesylate, is an amphetamine with a high potential for abuse. It has a half-life of less than one hour and can typically be detected in urine for 2–3 days.
Xanax, the brand name for alprazolam, is commonly prescribed for anxiety and panic disorders and has an average half-life of about 11.2 hours. In a urine drug test, a single dose can be detected for around 36 hours. For short-acting benzodiazepines, detection can last up to 5 days, while long-acting benzodiazepines may remain detectable for up to 30 days in regular users.
Valium is another benzodiazepine and is the brand name for diazepam. It has a half-life of approximately 1 to 3 hours.
The safest way to remove drugs from your system is through a medically supervised detox. Quitting cold turkey can be dangerous and may lead to life-threatening withdrawal complications.
If you’re concerned about your situation, it’s important to consult a doctor or addiction specialist for guidance. During a medical detox, patients are closely monitored as they navigate the early stages of sobriety and manage withdrawal symptoms.
Drug withdrawal happens when someone has developed a physical or psychological dependence on a substance. When the drug is suddenly absent, it can trigger uncomfortable—and sometimes dangerous—withdrawal symptoms. This risk is particularly high with alcohol, benzodiazepines, and opioids. Withdrawal from these substances can lead to:
Drug addiction is serious and shouldn’t be taken lightly. If you or a loved one is struggling and worried about withdrawal when trying to quit, it’s important to reach out to addiction professionals for guidance.
At Arizona IOP, our team of case managers, experienced clinicians, and addiction specialists is ready to provide support and care. We offer personalized programs to manage withdrawal and support recovery safely—whether through structured outpatient programs or supervised care.
Call our team today to take the first step toward recovery.
