How Long Does Fentanyl Stay in Your System?

how long does fentanyl stay in the system

Fentanyl is a potent synthetic opioid that is 50 times more powerful than heroin and 100 times stronger than morphine.[1] When used for recreational purposes, fentanyl can be found in the form of a powder, blotted on paper, or mixed with heroin, cocaine, and other street drugs to make them more potent. Fentanyl is also a prescription drug intended to treat severe and chronic cases of pain.

Fentanyl abuse is extremely dangerous, as it often leads to fatal overdoses. This drug has claimed the lives of many Americans, as it is often used as an adulterant in other drugs.

Knowing how long fentanyl stays in your system can prevent you from accidentally taking too much and suffering from an overdose. 

How Long Does it Take Fentanyl to Leave Your System?

It is important to understand that fentanyl’s half-life determines how long it will stay in your system. Elimination half-life refers to how long it will take for half of a dose of a drug to leave your body. 

The elimination half-life of fentanyl is dependent on the method of use. The half-life varies depending on if you inject fentanyl, use a patch, or a lozenge. 

When taken intravenously, fentanyl has a half-life of approximately 2-4 hours, which means it takes around 11 to 22 hours to leave your system. If you use a patch or lozenge, fentanyl has a half-life of 7 to 17 hours. This means it will leave your system after 36 hours.[2]

As fentanyl is broken down in your body, it leaves behind metabolites. These metabolites will stay in your system longer and are what drug tests are screening for. In other words, a drug test could detect fentanyl in your body for a longer period due to the metabolites that the drug leaves behind. 

Does Fentanyl Show Up on a Drug Test?

While fentanyl is stronger and more dangerous than other opioids like morphine, it is not tested for on a standard drug test. Standard drug tests often look for the metabolites left behind from morphine, instead of fentanyl. However, an advanced screening can be requested which can reveal the presence of fentanyl in your system.


While often undetected by standard urine tests, an advanced urine test can be used to identify fentanyl. On these urine tests, fentanyl can be detected 8 to 24 hours after you use the drug. This depends on various factors including weight, age, overall health, and more.


Blood testing is one of the least effective drug tests for fentanyl. This is because the substance can only be detected in the bloodstream for up to 12 hours after your last use of the drug. While this drug is only in the blood for less than a day, fentanyl can cause life-threatening health conditions such as organ failure and overdose when abused.


Saliva can be used for a variety of tests, from DNA to drug testing. When you are given a saliva drug test, the doctor will take a swab of your saliva from the insides of your mouth. These tests are more accurate when testing for fentanyl because they can detect the substance for 1 to 4 days.


Hair tests are not used as often because of how expensive the tests are to conduct, but because of how slowly hair grows, this type of test provides an accurate health history timeline.

Fentanyl and other drugs can be detected in the hair for up to 90 days. 

Factors that Influence How Long Fentanyl Stays in Your System

How long fentanyl stays in your system depends on a variety of factors. One of these factors is your metabolism. Just like how your metabolism can be faster or slower than others regarding food, it can affect how long drugs stay in your system, too. 

Other factors that influence how long fentanyl stays in your system include:

  • Age 
  • Weight 
  • Height 
  • Body mass 
  • Body fat 
  • Genetics 
  • Food intake 
  • Liver functioning 
  • Metabolic rate 
  • Urinary pH
  • Your dosage when taking the drug 
  • Route of administration
  • Frequency of use 
  • Duration of use 
  • Whether you used other drugs with the fentanyl 

If you had been using fentanyl for years, the substance may stay in your system longer than others. This is because the substance builds up in your body over time, leading to a higher number of metabolites in your body.

Finding Help for Fentanyl Abuse and Addiction

Fentanyl is a dangerous drug that can lead to addiction after only one or two uses. This drug is considered to be a main player in the opioid epidemic, as just a small amount of the substance can lead to a fatal overdose, so it is important to avoid it at all costs.

At Moving Mountains Recovery, we understand how serious addiction to opiates is. We are passionate about helping people find freedom from their addiction and rebuild their lives on a strong foundation of recovery. We have a team of motivated and compassionate professionals that are dedicated to helping people recover. 

If you or a loved one are struggling with fentanyl addiction, contact Moving Mountains Recovery Center today to learn about your treatment options.


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