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How Long Does Heroin Stay in Your System?

What Is Heroin?

Heroin is one of a group of drugs known as opiates. The drug has strong painkilling and sedative (‘downer’) effects. Most often Heroin comes in powder form. It can vary in colour from white to brown. Users can inject it, sniff it or smoke it on foil or in a tobacco-based joint.

Users of Heroin take the drug because it gives them a feeling of warmth and well-being. Larger doses can make users feel sleepy and very relaxed. Heroin is also a highly addictive drug and there is a significant risk of overdose when using the drug. This can lead to coma and respiratory failure, leading to death.

The effects of Heroin can last anywhere from a few minutes to hours, but the drug can stay in your system for much longer. The end of a heroin high doesn’t necessarily mean it’s out of your body. Certainly, this drug can remain in the body for much longer than many people expect it would.

Heroin has various street names such as Smack, Skag, Horse, H, Gear and Brown.

The Risks

Heroin is an extremely addictive and dangerous Class A illegal drug. It poses severe health risks including overdose, which kills more people in the UK than any other illegal substance. Tolerance builds rapidly, so doses tend to increase over time. Stopping even briefly can lower tolerance and increase overdose risk if resuming the same dose.

Injecting heroin can lead to vein and artery damage, infections, blood clots, and spreads blood-borne illnesses like HIV and hepatitis. Overdose is more likely when injecting or taking heroin with other sedatives like alcohol or benzodiazepines. Additional health risks come from common additives to increase profits.

Long-term heroin use changes brain chemistry, leading to intense cravings that make addiction very difficult to overcome without treatment. Proven methods involve prescribed replacement therapies like methadone, talk therapy, and social support. Relapsing after quitting can easily lead to overdose due to reduced tolerance.

The Law

Possessing heroin can result in seven years imprisonment plus unlimited fines. Supplying or selling carries up to life imprisonment. Driving under the influence can lead to fines, licence suspension, or jail time. Police can prosecute property owners and managers where supply occurs on their premises.

How Long Does Heroin Stay in Your System?

There are many variables that will determine how long heroin is detectable in the body. One important consideration is the type of drug test being used to do the testing (urine, saliva or hair) as each type of tests works within a specific timetable of detection.

Drug tests that check for heroin are actually checking for a selection of compounds that includes heroin, morphine and codeine. These are all opiates.

Heroin is only detectable within a short time frame with some types of drug tests. Other types of drug tests can still pick up drug usage up to three months later.

Another important factor that will determine how long heroin is detectable in the system is the physical makeup of the individual. Here a number of variables combine – body mass, physical activity, state of health, hydration – making it virtually impossible to indicate an exact amount of time in which heroin will show up on a drug test.

Detection Times for Heroin

Heroin can be detected by various testing methods. Saliva drug tests are best for detecting very recent use or for impairment. Urine tests detect drug use in the last few days. A hair follicle test offers the longest history but can’t be used until a week after drug usage.

The most common type of drug test is the urine drug test. Here drug test manufacturers make test membranes for detecting heroin in 2 sensitivities. The less sensitive membrane OPI works with a cut-off of 2000 ng/mL, which is the US standard for Opiates tests. The more sensitive MOR membrane works with a cut-off of 300 ng/mL, giving it a longer detection window.

At Zoom Testing, we offer the sensitive, 300 ng/mL Opiates Test for Heroin (MOR)

The following is an estimated range of detection times for Heroin using the three main types of drug test:
Saliva Drug Test: Up to 48 Hours
Urine Drug Test: 2-14 days
Hair Follicle Drug Test – up to 90 days

Factors Affecting Detection Time

Many variables influence how long heroin stays detectable in the body. These include:

Dose – Higher and more frequent doses lead to larger accumulations in fatty tissues, extending detection times. Even a single very large dose takes longer to fully metabolise and excrete.

Route of Administration – Injected and smoked heroin cross the blood-brain barrier fastest, resulting in quicker effects. This also speeds distribution into fatty tissues and clearance from the body. In contrast, sniffing takes longer to absorb and leave the body.

Individual Variation – Many personal characteristics affect retention times. These include:

  • Body fat – Heroin accumulations in fatty tissues increase detection periods. Those with higher percentages of body fat retain opioids longer.
  • Metabolism – Speed of liver metabolism helps determine elimination rates. Faster metabolisers clear heroin quicker than slow metabolisers.
  • Kidney function – Poor kidney function reduces heroin excretion through urine. Healthy kidneys filter blood faster, shortening detection windows.

Hydration Levels – Well hydrated people dilute drug traces in urine, leading to lower concentrations. Dehydration concentrates urine metabolites, increasing detectable levels.

Testing Type – Test sensitivity ranges widely, from 1 day for saliva to 3 months with hair testing. More sensitive assays identify lower residue levels over longer times.

Heroin Metabolism

Once in the bloodstream, heroin breaks down rapidly into morphine and other metabolites. Active morphine then further converts into inactive morphine compounds. Traces of these derivatives deposit in tissues throughout the body.

Fatty areas with reduced blood flow act as long-term stores, while better perfused organs like the brain release heroin metabolites quicker. As molecules return to circulation, kidneys filter out traces for excretion in urine.

Improving Clearance Times

While detection windows depend heavily on individual variation, some general measures may hasten heroin clearance:

  • Staying hydrated to dilute urine and increase kidney filtration
  • Avoiding further heroin use to prevent accumulating more residues
  • Increasing cardio exercise to burn fat stores and improve circulation
  • Supporting liver function through a healthy diet to metabolise traces faster

However, the only guaranteed way to pass a drug test is to abstain from using. Heroin stores can persist in the body for weeks after last usage. Consulting an addiction specialist can help create an integrated treatment plan.


Photo Credit: “BP” (CC BY-SA 2.0) by Symic

Zoom Testing is a leading UK drug testing company and a supplier of Drug Test Kits.

This post was originally published in 2014. It was last updated in November 2024.


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