Does Fentanyl Last Longer Than Heroin?

The effects of fentanyl, like heroin, last much longer than the initial high it produces. The half-life of fentanyl will also heavily depend on the route of administration.

Fentanyl is a synthetic (artificial) opioid often used in anesthesia and prescribed to treat severe pain. It is a Schedule II drug, which means it has medicinal use but is highly addictive. Fentanyl can also be made on the street. It is usually mixed with other substances and comes as a tablet or powder.

Heroin is a semi-synthetic and illicit opioid. It is made from morphine which comes from the seeds of an opium plant. Heroin is a Schedule I drug, which means it has no medicinal value, and addiction is almost guaranteed.

Fentanyl is 50 to 100 times more potent than morphine and 30 to 50 times more potent than heroin. It is an extremely dangerous and lethal drug, even in the smallest amounts. It takes about a 30 mg dose of heroin to be lethal. It only takes about a 3 mg dose of fentanyl to be lethal; either of these doses is enough to kill an average-sized man.

Here is what the DEA says about Fentanyl and Heroin:

Fentanyl is a synthetic opioid that is 50-100 times stronger than morphine. Pharmaceutical fentanyl was developed for pain management treatment of cancer patients, applied in a patch on the skin. Because of its powerful opioid properties, Fentanyl is also diverted for abuse. Fentanyl is added to heroin to increase its potency, or be disguised as highly potent heroin. Many users believe that they are purchasing heroin and don’t know that they are purchasing fentanyl – which often results in overdose deaths. Clandestinely-produced fentanyl is primarily manufactured in Mexico. (DEA)

Both of these drugs are dangerous and especially these days. Either can cause an overdose, and when mixed, the potential for overdose or an overdose death is almost imminent.

Does Fentanyl Last Longer Than Heroin?

How Long Does Fentanyl Last?

The effects of fentanyl, like heroin, last much longer than the initial high it produces. The time it stays in one’s system depends on how it was ingested, the amount is taken, and past use. Fentanyl can be detected in the urine between 24 to 72 hours after the last use. The metabolites of fentanyl (norfentanyl) can be detected for up to 96 hours after the last use.

The half-life of fentanyl varies depending on the route of administration. In intravenous Fentanyl, the half-life is between 2 to 4 hours, depending on the dose. Half of the amount ingested is broken down in 2 to 4 hours. Then another half of the amount left in the system is metabolized in another 2 to 4 hours. This continues until the drug has completely left the system. Transdermal Fentanyl, usually a patch applied to the skin, has a half-life of about 17 hours. When taken orally, fentanyl has a half-life of 5 to 14 hours.

How Long Does Heroin Last?

Heroin does not last long in your body. You get an intense initial euphoric rush, and the drug is quickly broken down into metabolites and byproducts (morphine). This means that while the initial effects or high of heroin are short-lived, the byproducts are still in the body, so the general effects are usually felt for a few hours. This can cause an individual to seek another dose while the metabolites remain in their system. Taking too much of the drug causes an overdose or fatal overdose.

Heroin is rapidly broken down in the body; it has a half-life of 2 to 6 minutes. This means that half of the heroin ingested is broken down into morphine in 2 to 6 minutes. Then, after another 2 to 6 minutes, another half of what is left in one’s system is metabolized. The exact amount of time heroin stays in your system depends on the amount of drug taken, the route of administration, and past use as well. A urine drug test can detect heroin for several hours up to 3 days after an individual’s last use.

Does a Fentanyl High Last Longer Than Heroin?

Yes, fentanyl does last longer than heroin. Both fentanyl and heroin are short-acting opioids. They both produce quick and intense euphoric highs, but that is short-lived. Debilitating withdrawal symptoms for both heroin and fentanyl can appear between 6 to 24 hours for heroin and 6 to 36 hours for fentanyl. Often an individual will continue to use it out of fear and to prevent withdrawal from occurring. There is help available.

Treatment for Fentanyl and Heroin Addiction

Treatment for opioid addiction has come a long way. It is safer to detox off of opioids in a medically supervised treatment environment. You don’t have to suffer any longer. Absolute Awakenings is committed to providing long-term recovery for those struggling. Everyone is different regarding their needs, so recovery should be an individualized experience. We provide a unique experience for each person that comes through our doors. Let us help you get on the road to a lasting recovery. Call us today!


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  3. Huecker MR, Koutsothanasis GA, Abbasy MSU, Marraffa J. Heroin. In: StatPearls. StatPearls Publishing; 2022. Accessed January 17, 2023.
  4. Bond A. Why fentanyl is deadlier than heroin, in a single photo. STAT. Published September 29, 2016. Accessed January 17, 2023.
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Amanda Stevens, BS

Amanda Stevens, BS

Amanda is a prolific medical content writer specializing in eating disorders and addiction treatment. She graduated Magnum Cum Laude from Purdue University with a B.S. in Social Work. As a person in recovery from disordered eating, she is passionate about seeing people heal and transform. She writes for popular treatment centers such as Infinite RecoveryAscendant NY, The Heights Treatment, New Waters RecoveryGallus DetoxRecovery UnpluggedOcean RecoveryRefresh Recovery and adolescent mental health treatment center BasePoint Academy. In her spare time she loves learning about health, nutrition, meditation, spiritual practices, and enjoys being the a mother of a beautiful daughter.

Last medically reviewed January 17, 2023