How Long Do Drugs Stay in Your System? - Addiction Answers

How Long Do Drugs Stay in Your System?

Over 30 million people in the USA regularly use illicit drugs. This includes everything from marijuana and tobacco to methamphetamine. After hearing this stat, you’re probably wondering: how long do drugs stay in your system?

The answer is: it depends. Different drugs affect your body differently and stay in your system for different amounts of time. If you have a drug test coming up and need to plan for it, keep reading.

In this article, we’ll break down everything you need to know about how long drugs stay in your body.

Drugs in the system

How Long Do Drugs Stay in Your System?

Like we said: it depends. That’s not a satisfying answer, but it’s the truest. Some drugs stay in your system for 30 days and longer; others are flushed out within 24-48 hours.

The type of drug you take is the biggest determining factor in how long it will stay in your system. However, other factors affect it as well. Your weight, height, exercise level, and metabolism can make a drug flush out faster or slower than expected.

Here are a few other factors that can affect the survival of drugs in your system:

  • Age
  • Weight
  • Dosage
  • Metabolism
  • Drug tolerance
  • Hydration levels
  • Hunger
  • Sex and gender
  • Urine acidity
  • Method of intake (snorting vs. smoking, etc.)
  • The drug’s half-life (how quickly it deteriorates)

Everybody is different, and so the numbers that we’ll be citing in this article are averages. Drugs may leave your system more quickly, and they may linger. It all depends on your lifestyle.

What Drugs Stay in Your System the Longest

To understand why a drug stays in your system, you have to understand its half-lives. A half-life is how long it takes for the drug to deteriorate to half its original amount.

Half-lives determine how long the drug will be affecting your body. Marijuana has the longest half-life of common drugs; it can take up to 7 days to reach a 50% concentration. The half-life also generally represents how long a drug is detectable in your urine.

Marijuana, opiates, and amphetamines are known for their long half-lives. However, even when they are not detectable in your urine, they can still be found in your body.

Different Types of Testing

When you think of a drug test, you probably imagine a little cup of urine. That’s one of the most common methods for drug testing, but there are other methods as well.

Different types of testing are done to gain different information. Hair tests, for example, can show a comprehensive profile of drugs taken in the last few weeks. Saliva tests, by contrast, only show what was taken in the last few hours.

Here are the most common drug tests given:

  • Urine test: the most common and least expensive, most drugs are detectable 
  • Blood test: not used often, only shows what is currently in the bloodstream
  • Hair test: more expensive, but also more thorough; can show the last 90 days of drug use
  • Saliva test: uncommon, does not yield strong results

Common Drugs and How Long They Last

Here’s what you’ve been waiting for: the numbers. Remember that these are estimates, and you may see drugs remain in your system for longer than expected. The only way to ensure you test clean is to stay clean.


Cannabis has a very long half-life. THC can be detected in urine for up to a month, so avoid marijuana if you have a test coming up.

Urine: 30 days

Blood: 4 hours

Hair: 90 days

Saliva: 72 hours


Some drug tests will check for alcohol in your system. It deteriorates quickly but can be detected.

Urine: 10-12 hours

Blood: 10-12 hours

Hair: 90 days

Saliva: 12 hours


Also known as uppers, stimulants are a class of narcotics that give you an addictive high. They fade fast but can be found in your system for weeks.

  • Cocaine
    • Urine: 3 daysBlood: 24 hours

      Hair: 90 days

      Saliva: 2 days

  • Ecstacy
    • Urine: 4 daysBlood: 2 days

      Hair: 90 days

      Saliva: 2 days

  • Methamphetamine
    • Urine: 7 daysBlood: 3 days

      Hair: 90 days

      Saliva: 2-4 days

  • Adderall
    • Urine: 3 daysBlood: 2 days

      Hair: 90 days

      Saliva: 4 days



Hallucinogens separate the user from reality, sending them on a “trip.” There are man-made hallucinogens, like LSD, and naturally occurring ones, like psilocybin (also known as magic mushrooms).

  • LSD (acid):
    • Urine: 4 daysBlood: 12 hours

      Hair: 90 days

      Saliva: not detectable

  • Psilocybin:
    • Urine: 24 hoursBlood: 24 hours

      Hair: 90 days

      Saliva: not detectable

  • Ketamine:
    • Urine: 11 daysBlood: 4 days

      Hair: 90 days

      Saliva: not detectable


There is an opioid epidemic in America at present. Overprescription has made these drugs widely available. They’re deeply addictive.

  • Codeine:
    • Urine: 3 daysBlood: 4 days

      Hair: 90 days

      Saliva: 4 days

  • Heroin:
    • Urine: 3 daysBlood: 6 hours

      Hair: 90 days

      Saliva: 1 hour

  • Oxycodone:
    • Urine: 4 daysBlood: 24 hours

      Hair: 90 days

      Saliva: 2 days

  • Morphine:
    • Urine: 3 daysBlood: 3 days

      Hair: 90 days

      Saliva: 3 days


Also known as muscle relaxers, these are usually prescribed to treat chronic pain and anxiety. Benzos have a long half-life. They’re also incredibly addictive.

  • Ativan:
    • Urine: 6 daysBlood: 3 days

      Hair: 30 days

      Saliva: 8 hours

  • Valium:
    • Urine: 6 weeksBlood: 48 hours

      Hair: 90 days

      Saliva: 10 days

  • Xanax:
    • Urine: 4 daysBlood: 24 hours

      Hair: 90 days

      Saliva: 48 hours

An Ounce of Prevention

We hope after reading this article, you’re no longer asking yourself, “how long do drugs stay in your system?”. There are many products that claim to cleanse your body of drugs, but be cautious. The only way to make sure there are no drugs in your system is to not take any.

If you or a loved one are seeking treatment for addiction, you are not alone. Addiction Answers is dedicated to giving you the resources you need to heal. We’re a judgment-free organization working for a better, addiction-free tomorrow.

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