How Long Does Fentanyl Stay in Your System?

Fentanyl is a potent synthetic opioid and prescription medication for severe pain. The substance has reached the media spotlight over the last few years due to its devastating overdose death statistics, reaching over 100,000 from December 2020 – December 2021 alone. Approximately 50 to 100 times stronger than morphine, non-prescription fentanyl is manufactured illegally and often added to other substances such as heroin, cocaine, and methamphetamine. One of the most prominent questions regarding the drug is, “How long does fentanyl stay in your system?”


While results vary, most studies indicate that the effects of fentanyl can last for 72 hours, and the substance can remain in the body for seven days.


Even with the knowledge of its half-life and metabolites, fentanyl still requires a close examination to prevent overdoses and deaths in the future. GateHouse Treatment has seen the detrimental consequences of the substance, so we wish to provide critical insights and statistics on its effects, potency, and detection times.

What is the Purpose of Fentanyl?

Most applications and prescriptions for fentanyl are for short- and long-term pain management. Approved by the Food and Drug Administration for use as an analgesic and anesthetic, it produces various effects, such as:

  • Relaxation
  • Euphoria
  • Sedation
  • Drowsiness
  • Respiratory depression
  • Dizziness
  • Nausea and vomiting

How Does Someone Properly Consume Fentanyl?

When someone receives a fentanyl prescription, they usually take it intravenously (IV), transdermally as skin patches (TD), intrathecally as a nasal spray (IT), or in the form of a cough drop. Like morphine, most prescriptions or applications follow surgery or chronic pain where the person is physically tolerant to other opioids. In this form, the amount of fentanyl administered is minimal and provides relieving effects in a safe and controlled manner. In its prescription form, fentanyl takes names such as Actiq®, Duragesic®, and Sublimaze®.

How Does Someone Improperly Consume Fentanyl?

Synthetic fentanyl, primarily responsible for the recent surge in overdoses, is illegally manufactured in a lab and often cut or mixed into other drugs like heroin, cocaine, methamphetamine, and MDMA. In this form, drug dealers often sell it as a powder, drop it onto blotter paper, put it in eye droppers or nasal sprays, and make it into pills that resemble other opioids. Most people consuming synthetic fentanyl do so without knowing, receiving the substance from other drugs.

Why Would Someone Mix Fentanyl Into Other Substances?

Fentanyl takes very little to produce a significant high, making it a cheap option for drug manufacturers. For instance, someone who illegally produces and distributes heroin may mix fentanyl into their product to use less heroin per dosage and save money. Further, the highly addictive nature of fentanyl creates a much larger profit margin as users return and purchase the drugs more often. In this case, an occasional loss or two of a client has no impact on the manufacturer’s bottom line, fueling a vicious cycle of financial gains for human life.

How Does Fentanyl Affect the Body and Mind?

Fentanyl works by binding to the body’s opioid receptors in areas of the brain that control emotions and pain. Like other opioids, the brain adapts to prolonged use and diminishes its sensitivity; this makes it harder to feel pleasure from anything other than the substance, quickly leading to addiction and a complete takeover of a user’s life.

Overdoses are incredibly prevalent with fentanyl, particularly synthetic. Since the substance impacts respiratory function, users who overdose on fentanyl usually experience slow or complete cessation of breathing. In turn, they limit the amount of oxygen reaching their brain in a condition known as hypoxia, which can lead to a coma, permanent brain damage, or death.

Non-life-threatening effects of a fentanyl overdose include, but are not limited to:

  • Stupor
  • Changes in pupil size
  • Cyanosis (discoloration of skin from poor circulation)
  • Coma
  • Respiratory failure

What is the Half-life of Fentanyl, and Why Does This Matter?

The half-life of fentanyl is approximately three to seven hours, but what does this statistic mean in terms of reducing overdoses? When referring to a substance’s half-life, this measurement indicates how long it takes for the active substance to reduce by half in your body. A drug’s half-life varies depending on the user’s body processes and genetic factors.

Knowing this measurement is essential because shorter half-lives, like in fentanyl, dramatically increase the potential for withdrawal complications. A substance’s half-life can also indicate how long it will take to reach a stable level in the body upon initial administration. Usually, it takes about five times the drug’s half-life to build stability in the body. Once this level becomes stable, early side effects diminish.

Half-life becomes particularly important when discussing fentanyl because it can produce severe withdrawal symptoms that can begin a few hours after someone takes it. Some of these symptoms of withdrawal include:

  • Muscle pain
  • Sleep problems
  • Diarrhea or vomiting
  • Severe cravings
  • Uncontrollable leg movements
  • Cold flashes and horripilation (goose bumps)

How Long Does Fentanyl Stay in Your System by Usage?

The effects of fentanyl can last from 30 minutes to 3 days, heavily determined by factors such as how soon it starts working, the intensity of impact, and the usage method. As with most drugs, smoking or injecting it into the body causes the substance to reach blood and the brain much faster than through the nose or mucus membranes. Oral consumption is the slowest method since the drug must pass through the stomach and intestines before reaching the bloodstream and brain.

Several factors can affect the detection times of fentanyl, including:

  • Age
  • Weight, body fat, and body mass
  • Genetics
  • Method of intake
  • Liver function
  • Frequency and duration of use
  • Simultaneous use of other substances

While there is no specific timeline when answering the question, “How long does fentanyl stay in your system?” fentanyl appears to take much longer than other short-acting opioids. Heroin, for instance, generally lasts in the body between 2 to 4 days. In contrast, fentanyl can appear in samples for weeks, while byproducts can stay detectable for months.

Again, these specific measurements vary based on frequency of use and an individual’s metabolism. A person who’s used fentanyl once or twice can process and remove the substance much faster than someone who regularly uses it. For chronic users, fentanyl can remain detectable for up to 26 days after the last usage.

How Long Does Fentanyl Stay in Your System by Test Type?

The duration that fentanyl stays in the body also changes based on the type of drug test used for detection. On average, it can appear on a urine test between 24 and 72 hours and a hair follicle test for up to three months. While blood tests are considered invasive, clinics may use them for someone unable to produce a urine screening for fentanyl. In this case, detection can last up to 20 hours intravenously, three days orally, and 3.5 days transdermally.

GateHouse Treatment Can Help Reduce the Risk of Fentanyl Overdose

GateHouse Treatment offers comprehensive addiction services to combat and treat various substance use disorders such as fentanyl and opioids. Inarguably, the best way to avoid the pitfalls of fentanyl use is to stay away from the substance altogether. However, life takes many unexpected turns, and we’re all susceptible to paths we don’t anticipate. We provide multiple addiction treatment programs, such as partial hospitalization (PHP), intensive outpatient (IOP), and outpatient (OP), for those who find themselves on an unfamiliar and seemingly unforgiving path.

GateHouse Treatment allows clients to build a new life focused on sobriety and recovery with peer-group support and help from behavioral therapy and mental health professionals in the field. If you or a loved one struggles with fentanyl or opioid use, call us at (855) 448-3588 or visit our website to learn how we can help.

Corey Rando

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