How long does marijuana stay in your system?

Gail Evans, Alphabiolabs

By Gail Evans, Technical Trainer at AlphaBiolabs
Last reviewed: 01/27/2023

According to the Centers for Disease Control and Prevention (CDC), marijuana is the most commonly used federally illegal drug in the US, used by more than 52.5 million people across the country.

In this article, we take a closer look at marijuana, how long the drug stays in your system, and the long-term effects of marijuana use.

What is marijuana?

Marijuana, also commonly referred to as weed, dope, cannabis or hash, is a plant-based drug derived from the Cannabis sativa or Cannabis indica plant.

It is extremely popular among recreational drug users and is often sold as a soft lump of dried brown or green herbs.

Skunk, a particularly potent strain of marijuana, is typically bright green in appearance, and covered in tiny crystals.

Another common form of marijuana is cannabidiol (CDB) or CBD oil – a light yellow or amber liquid that is sold online and in select shops.

Marijuana is most commonly inhaled (smoked or vaped), but some people also add it to food and drink products such as teas, candies and cakes. Food and drink products containing marijuana are known as ‘marijuana edibles’ or ‘edibles’.

Although some states have legalized marijuana for medicinal and/or recreational purposes, marijuana is a Schedule I substance under the Controlled Substances Act, meaning it remains illegal at a federal level due to its potential for abuse and dependency.

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What does marijuana do to you?

It is important to remember that drugs affect different people in different ways, so not everybody will have the same experience while using the same substances. Drugs can even affect the same person differently when taken at a different time.

Marijuana is classed as a psychoactive drug and can have different effects depending on the person taking it, their mood, how much marijuana they have taken, frequency of usage and how much tetrahydrocannabinol (THC) it contains: the main psychoactive compound found in marijuana.

When a person consumes marijuana, THC is released into the body, altering normal brain communication, and affecting thinking, memory, movement, pleasure, and concentration.

This is why some marijuana users feel more relaxed, others become giggly and chatty, and some people become confused, paranoid, and anxious.

Marijuana can also cause other physical side effects such as lethargy, drowsiness, and increased hunger. Mild hallucinations can also occur, as can sickness and nausea.

How long does marijuana stay in your system?

When a person uses marijuana, a proportion of the drug and its metabolites are released into the bloodstream, with a small amount being excreted by the body in a variety of ways.

How long marijuana remains in the system and how quickly a person might feel the effects depends on several factors including how the drug was ingested, how often it is used, and the metabolism and weight of the individual.

For example, when smoked, the effects of marijuana can be felt in as little as 60 seconds. When eaten, its effects can be felt in up to 45 minutes and can last for 2-4 hours.

It is important to note that when taken in large quantities, it can take days for a person to feel normal again after consuming marijuana.

Is marijuana addictive?

Yes, marijuana is addictive. People who use marijuana regularly may experience cravings and withdrawal symptoms when they stop using it, leading to the development of harmful addictions.

When an individual ingests marijuana, either through smoking, vaping, or eating it, this alters the way the brain works and causes it to release dopamine.

Dopamine, the brain’s ‘feel-good’ chemical, creates feelings of euphoria, pleasure, and reward. These powerful sensations cause some people to become addicted and dependent on marijuana.

People who use marijuana on a regular basis are also more likely to build up a tolerance to it. This means that they will require even more of the drug over time to experience the same ‘high’.

How long does it take for marijuana to show up in a drug test?

Even after the ‘high’ has worn off, and long after the drug was first consumed, marijuana use can be detected by a drug test, depending on the type of test you take.

Oral fluid (saliva) tests can detect marijuana for up to 48 hours, while urine drug tests can detect a single-use of marijuana for up to four days after it has been consumed.

Chronic heavy use of marijuana can be detected up to 30 days after being ingested using the same urine drug testing methods.

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The rate at which head hair grows means that head hair tests provide a wide window of detection for marijuana use, making it possible to detect concentrations of THC in the body for up to 12 months, depending on the length of the hair.

Similarly, nail drug testing can be used to provide an overview of up to 12 months for drug use (six months for fingernails and 12 months for toenails).

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What factors affect how long marijuana stays in your system?

How long marijuana remains in a person’s system depends on several factors including:

  • How much of the drug was consumed
  • Frequency of consumption
  • The person’s body mass index (BMI), weight and metabolism
  • The method of consumption (e.g. smoked, vaped, eaten)

What are the long-term effects of marijuana use?

Although the effects of marijuana can wear off in as little as an hour, depending on how much was consumed, regular marijuana use over a prolonged period has been linked to several long-term psychological and physical problems, including:

  • Coughing
  • Increased heart rate and blood pressure
  • Fertility concerns
  • Anxiety, paranoia, and mood swings
  • Difficulty sleeping
  • Poor mental health episodes including schizophrenia

How can I find out if a loved one is using marijuana?

AlphaBiolabs offers two types of home drug tests, designed to give you peace of mind or enable you to seek support for a loved one who is struggling with substance misuse.

  • Home Urine Drug Test Kit (pack of 3 – $34.95) – this easy-to-use home drug testing kit can detect drugs and their metabolites in a urine sample. The self-contained screening kit includes built-in test strips, allowing you to read the results in just 5 minutes
  • Drug and Alcohol Nail Test (from $99) – this test can detect drug use for a period of up to 12 months prior to samples being collected, with only a sample of fingernail clippings or toenail clippings required. Simply follow the instructions included in your test kit to collect your nail clipping samples and return them to our accredited laboratory for testing

Please be aware that our home drug test kits are for peace of mind only, and the results cannot be used in court or for legal reasons.

For confidential advice about which test might best suit your needs, you can email our Customer Services team at

Home Drug Tests

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Gail Evans AlphaBiolabs

Gail Evans

Technical Trainer at AlphaBiolabs
A professionally-trained forensic scientist, Gail joined AlphaBiolabs in 2012 and holds the role of Technical Trainer. Her day-to-day responsibilities include delivering in-depth training sessions both internally and externally, covering DNA, drug, and alcohol testing. Before joining the company, Gail was a practising forensic scientist, attending scenes of crime, and analyzing physical and biological material with potential evidential value. Gail also holds qualifications in chemistry and is a Lead Auditor for the ISO 9001 standard, the international standard for quality management.

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