Fentanyl is a synthetic opioid drug that is 50 times stronger than heroin and 100 times more potent than morphine. As a pain reliever, it is used to treat severe pain or as a general anesthetic.[1] When injected, fentanyl has a much shorter half-life than many other opioids, meaning it will also leave your system faster. However, exactly how long fentanyl stays in your system is dependent on many different factors, but understanding these factors can help you prevent an overdose and use medications more safely.

Due to the short detection periods and potent highs fentanyl can offer, some drug users may be tempted to use this drug. Others use it accidentally, not knowing that their other substances are laced with fentanyl. Whatever the case may be, if you or a loved one have fallen victim to fentanyl abuse, the time to get help is now.

Fentanyl Abuse and Addiction

Although fentanyl is used and prescribed in medical settings, it is also diverted for street use. When purchased on the streets, fentanyl may be called “china girl,” “china white,” “china town,” or “apache.”[2]

There are a number of different ways people abuse fentanyl and the method of administration can influence how long it stays in your system. For example, fentanyl can be abused by taking it orally, absorbing it through a patch on the skin, or smoking, snorting, and injecting it.[1]

Symptoms of fentanyl abuse include:

Symptoms of fentanyl abuse

  • Confusion
  • Euphoria
  • Sedation
  • Pinpoint pupils
  • Slurred speech
  • Dizziness or lightheadedness
  • Sleepiness
  • Itching
  • Nausea
  • Weakness
  • Flushed face
  • Slowed reaction time
  • Unconsciousness

The effects of fentanyl are similar to those of other opioids, however, they are far more intense. Fentanyl is one of the strongest opioids out there and can cause an overdose in even the smallest amounts.

How Long Do The Effects of Fentanyl Last?

Since fentanyl can be taken in so many different ways, the method of administration is determinant of how long the effects last and how long it may stay in your system. Even though fentanyl produces a fairly short-lasting high, it can last for 24 hours or more if taken via a transdermal patch. However, someone who takes fentanyl intravenously may notice that their high wears off after just 30 minutes.[3]

Depending on the method of administration, the half-life of fentanyl changes. It takes approximately 4-6 half-lives for a substance to completely leave the system. When injected intravenously, fentanyl has a short half-life of 2-4 hours. When taken orally or transdermally, however, fentanyl has a half-life of 7-17 hours.[4]

Even though the effects of fentanyl will wear off long before it is eliminated from your system, the drug will leave behind traces of itself in the form of metabolites. Metabolites are what drug tests screen for.

Does Fentanyl Show Up on Drug Tests?

Even though fentanyl is stronger and more dangerous than most other opioids, most standard drug tests do not recognize fentanyl. This is because drug tests look for metabolites – not actual drugs. And, since fentanyl doesn’t metabolize into morphine like other opioids do, many drug tests will not detect fentanyl. However, if the person administering the test sends the sample to a lab or testing, fentanyl can be detected via an advanced drug test.

Factors That Affect Fentanyl Detection Times

There is no way to say exactly how long fentanyl stays in your system because each person is different. There are many individual factors that influence drug detection times and how long drugs stay in the body. Most factors have to do with how your metabolism works, such as:

  • Age – younger people are usually in better health with faster metabolisms. This allows their bodies to break fentanyl down and metabolize it at a faster rate than older people.
  • Overall health – people with healthier organs and no underlying health conditions are able to metabolize substances like fentanyl at a faster rate than those in poor health.
  • Weight and BMI – people who are overweight or obese for their height may have slower metabolisms. They may also have more fat cells where substances can be stored and detected in the system.
  • Frequency of fentanyl use – how often a person takes fentanyl will influence how long it stays in their system. The more frequent your drug use, the longer it will take you to pass a drug test.
  • Duration of fentanyl use – similar to the frequency of use, how long a person has been addicted to fentanyl plays a major role in how long it takes to leave the system. The longer you have been using, the longer it will take to pass a drug test.
  • Dose – the higher dose you take, the longer it will take to be eliminated from your system.

Lastly, different types of drug tests have different detection windows. Blood tests can usually only detect substances for several hours or days after use, but hair follicle tests can detect some substances for 90 days or more. As a result, the amount of time it takes to pass a drug test depends on which type of drug test is used.

How Long Fentanyl Stays in Your System: Urine, Hair, Blood, and Saliva

Although fentanyl detection times vary from one person to the next, here is a general outline of how long you can expect fentanyl to stay in your urine, hair, blood, and saliva.[5]

  • Urine tests – can detect fentanyl for 8-24 hours after the last use
  • Hair follicle tests – can detect fentanyl for up to 90 days after the last use
  • Blood tests – may detect fentanyl for up to 12 hours after the last use
  • Saliva tests – can detect fentanyl for 1-3 days after the last use

Many people will try taking herbal supplements or increasing their water intake to get fentanyl out of their system, however, this is usually ineffective. The only medically advised method for rapid fentanyl detox involves sedating patients and putting them into immediate opioid withdrawal using naltrexone, an opioid blocker.

However, rapid-detox methods can be dangerous and are often ineffective. Instead, it is a better idea to detox from fentanyl the right way – at a medical detox facility.

Help for Fentanyl Abuse and Addiction

Fentanyl is not a drug you want to be experimenting with – no matter how many other opioids you have abused. It is far more potent and deadly and can cause an overdose within seconds.

If you or someone you love is abusing fentanyl, it’s time to get help. Pick up the phone and call today to speak with a dedicated treatment professional who can help you begin your sober journey.


  1. https://www.drugabuse.gov/publications/drugfacts/fentanyl
  2. https://www.dea.gov/factsheets/fentanyl
  3. https://www.ncbi.nlm.nih.gov/books/NBK459275/
  4. https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/016619s034lbl.pdf
  5. https://pubmed.ncbi.nlm.nih.gov/8452277/