How Long Does Heroin Stay in Your System?

Last Updated: May 26, 2023

Editorial Policy | Research Policy

Heroin is an illicit opioid used for recreational purposes in the United States and around the world. In the United States, there is no accepted medical use for heroin. In some countries, however, heroin (diamorphine) is used for surgery and cancer-related pain.

Heroin stays in the body for different amounts of time, depending on how it is ingested:

  • Saliva injected: 6 hours
  • Saliva smoked: 24 hours
  • Urine: 60 hours
  • Hair: Three to six months

Certain factors can change the detection window. For example, people who are older or who have a higher percentage of fat tissue will take longer to metabolize heroin.

Heroin is detectable in blood, saliva, urine and hair. The most common test for heroin and other  drugs of misuse is a urine screening. Urine tests are inexpensive, fast and non-invasive. Blood tests are rarely used to detect heroin because heroin leaves the bloodstream in about 30 minutes. Saliva tests are often more expensive and less reliable than urine tests. Though hair testing has the largest detection window, it is generally the most expensive option.

Duration of Effects of Heroin

Most people feel the effects of heroin for a few hours. The onset is rapid, with feelings of euphoria occurring seconds after injection.

How long do the effects of heroin last? How the drug is administered is the most important factor in determining heroin effects duration. Snorting and smoking will generate effects within a few minutes, while heroin taken orally works more slowly. An oral dose takes about 15 to 60 minutes to work and does not provide the same euphoric peaks as administration by other routes. Most people who use heroin prefer to snort, smoke or inject it for these reasons.

Half-Life of Heroin

The heroin half-life is three minutes, which means that half of the drug is gone in three minutes and almost all of the dose is gone within 15. However, its effects last much longer than this.

As the body changes and breaks down the structure of heroin, it creates 6-monoacetylmorphine (6-MAM). 6-MAM has a half-life of 30 minutes, so the body takes about three hours to clear it, prolonging the heroin high.

Heroin Screening Detection Times

Heroin detection time varies based on the type of test used. A blood test has a narrow detection window because the person must be high for a blood test to return positive. Mid-range tests are urine and saliva, with hair tests have the longest detection time.


A urine test is standard for most workplace testing scenarios. Heroin urine detection time is about 60 hours (two-and-a-half days) in urine but is longer with heavy usage. Since heroin exits the body very quickly, urine tests look for 6-MAM instead.


Heroin blood test detection time is about 30 minutes. Blood tests are not used for heroin except to determine if the person is currently high. Blood is usually only tested in the hospital in order to determine if symptoms are caused by drugs or a medical condition.


Heroin is detectable in saliva for up to 24 hours. The small detection window of saliva tests makes it a less popular option than urine drug screens.


Heroin hair tests can detect drug use that occurred up to three to six months ago, depending on the test and how fast the hair grows. Heroin deposits into hair follicles while in the bloodstream and remains in the hair while it grows.

Factors Affecting How Long Heroin Stays in Your System

Drug testing is not a perfect science, and many factors affect how long heroin is detectable. Some people will naturally break it down faster than others.

There are a few different factors that can change how quickly heroin is metabolized:

  • Amount used: Heavy heroin use increases the detection window for drug tests because it accumulates and stores in body tissue.
  • Frequency of use: Accumulation of heroin in the body may cause it to release slowly, even when the drug is not being used. Not enough would be released into the blood to feel high, but enough might be there to fail a drug test.
  • Method of use: This probably will not affect the testing window by much, but quicker-acting methods will leave the body more quickly. Taking heroin by mouth, for example, will make it detectable longer than if snorted, smoked or injected.
  • Purity of the drug: Higher purity means a higher chance to trigger a positive test. A highly pure product will last longer in the blood, urine and saliva.
  • Body fat percentage: Heroin and its metabolite 6-MAM are lipophilic, meaning they deposit into fat tissue. People with higher body fat percentages retain heroin for longer, and it continues to release for days after last use.
  • Liver and kidney function: People with impaired liver and kidney function will have higher amounts of heroin in their system for a longer amount of. No exact numbers are available, but the worse someone’s organ function is, the longer drug use can be detected.

False Positives for Heroin

A positive urine, saliva or hair screen does not confirm that a drug was actually used. To confirm, a testing center will send the sample for confirmation by gas chromatography-mass spectrometry (GC-MS).

GC-MS is very sensitive and specific and can rule out a false-positive result. Therefore, GC-MS will not trigger false positives in the same way a urine drug screen will.

Drugs that may trigger a false positive for opioids include:

  • Antibiotics, fluoroquinolones, rifampin
  • Antipsychotics
  • Naloxone, used to reverse an opioid overdose
  • Poppy seeds
  • Some over-the-counter allergy medications
  • Tricyclic antidepressants

How Is Heroin Eliminated From the Body?

Metabolism of heroin occurs almost entirely in the liver, with less than 1% leaving the body through the kidneys and urine. Enzymes in the liver break heroin into 6-MAM and morphine, which quickly enter circulation and begin causing effects in the brain.

People with liver damage, due to alcohol misuse or an infection like hepatitis, may metabolize heroin more slowly. This causes it to stay in the bloodstream longer.

If you or a loved one are experiencing heroin or opioid addiction, The Recovery Village Ridgefield is here to help. Contact us today to learn about treatment options that can work well in your situation. We can put you in touch with addiction professionals and help you start the road to recovery.


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    DrugBank. “Diamorphine – DrugBank.” 2018. Accessed July 17, 2019.

    Moeller, Karen; et al. “Urine Drug Screening: Practical Guide for Clinicians.” Mayo Clinic Proceedings, 2008. Accessed July 17, 2019.

    Sawynok, Jana. “The Therapeutic Use of Heroin: A Review of the Pharmacological Literature – Canadian Journal of Physiology and Pharmacology.” Canadian Journal of Physiology and Pharmacology, 2019. Accessed July 17, 2019.