How Long Does Marijuana Stay In Your System?

Tens of millions of drug tests every year are conducted for employment purposes alone. Most people have nothing to fear from them, but many candidates worry: what if that one puff of a joint last month shows up in my test?

 How Long Marijuana Stays in Your System?

There is no single, strictly-defined window for marijuana detection. Although it’s a common belief that 30 days is enough to get clean, in reality, it’s not as simple as that.

Many variables influence whether or not your cannabis consumption can be detected, and when. You will find a general guide here, but keep in mind that these factors vary from person to person.

Marijuana Compounds And Metabolites: What Is Being Tested?

Most marijuana consumers smoke the plant. When inhaling it, the active compounds of cannabis enter the lungs, where they are absorbed into the blood stream. From there, the compounds have an immediate effect on the endocannabinoid system of the human body.  The result is a marijuana high.

The compounds responsible for this high are tetrahydrocannabinol (THC), cannabidiol (CBD) and their metabolic byproducts (metabolites). Most drugs have water-soluble ingredients, so drinking water theoretically helps to flush the drug out of your system quicker.

But that is not the case for marijuana compounds. All of its chemicals are fat-soluble, meaning that they accumulate in fat cells throughout the body, and water will not help to eliminate them.

After the liver processes the primary compounds, they are divided into metabolites. THC, for example, produces the metabolite 11-nor-delta9-caboxy THC-COOH. These metabolites, being fat-soluble as well, can stay in the body for weeks and even months.

They can remain dormant in fat cells and become reactivated as a result of the person’s behavior (e.g. running, changing your diet). What this means is that you can test positive even if you’ve only smoked a small amount, and was in recent weeks.

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What compounds do marijuana tests look for?

Drug tests have two purposes: 1) to verify present intoxication, or 2) to check if the person has smoked in the past.

For immediate intoxication, the tests look for THC in the blood or urine. For past use, tests look for THC metabolites in the hair or in urine.

After inhaling cannabis smoke, THC levels rise for several hours. During that time, the presence of THC in the user’s body is easily detectable, even after a single inhalation. THC (or THC-COOH) concentration drops over time, but remain detectable for quite a long time, even after the individual stops using marijuana.

Testing for Immediate Use

When it comes to testing for intoxication, blood and saliva tests are sufficient.

Blood Serum Test. This test is the easiest to implement. It is often used as an investigative in car accidents. However, THC does not bond with blood cells, so it can only test for active intoxication.

Saliva Test. This test is the most recently-developed test and is not yet as common as blood tests. It is often used by police, however, because it is relatively quick and easy to undertake. The chemicals fade after several hours, so this test is primarily used in accident investigations.

Testing for Past Use

The study of past marijuana consumption utilizes very different types of screening. THC , by that time, will have completely decomposed in its metabolites, so what the tests look for is the THC-COOH molecule.

Hair Follicle Test. This test provides the most accurate results. Its principal benefit is that it can detect traces of marijuana many months after the last consumption. A single hair from anywhere on the body is sufficient for the screening. The major inconvenience of the test is its price – a hair follicle test is the most expensive of all marijuana screening tests.

Urine Test. This test is the most common method used to screen for the presence of cannabis. The test is very simple: urine samples are examined in a laboratory and screened according to a chosen threshold level. If the degree of the targeted chemical (usually THC-COOH) is higher than the standard threshold, the test returns positive.

Passing a Cannabis Drug Test

Choosing a test. Each of the tests has its own advantage. But the Substance Abuse and Mental Health Services Administration (SAMHSA) recommends the urine test, so that test is typically applied.

Choosing a sensitivity. The experimenter must determine the cut-off concentration (the threshold level) of the researched substance. The conventional cut-off for urine tests is 50 nanograms per milliliter. But they can vary between 15-100 ng/mL.

In fact, examiners often repeat the urine test. The first time typically has a cutoff of 50 ng/mL, and the second test, as a confirmation of the first, usually has a cutoff of 15 ng/mL.


What are the detection times of marijuana tests?

Detection times for marijuana vary from test type.

Single Cannabis Use:

  • Cannabis detection in saliva: 0-24 hours
  • Cannabis detection in blood: 6-24 hours
  • Cannabis detection in hair in rather unlikely in the case of a single use.

Regular Cannabis Use:

  • Marijuana detection in saliva: 0-24 hours
  • Marijuana detection in blood: 7 days
  • Marijuana detection in hair: 3+ months

For both one-time and regular users, it isn’t possible to establish a precise detection window for urine. There are too many other variables that come into play and can modify these results. See below.

What factors influence marijuana drug test results?

Factors that influence the results of a marijuana drug test include the frequency of consumption, individual physiology, user lifestyle, and the type of compound. Essentially, since THC metabolites are stored in body fat, the amount of body fat a person has determines how long the drug is detectable.

Despite the standards set by the SAMHSA regulating urine tests, the results can still be difficult to predict. Since each test type has a different detection window, there are other complications to take into account when predicting how long marijuana can stay in the system.

Frequency of Consumption

Occasional users: 3-4 days

First-time or occasional smokers can expect to test positive for up to three days. By day four, no traces of cannabis should be able to be detected in urine below the typical threshold of 50 ng/mL.

Frequent user: 7-70 days

Regular and frequent users usually can test positive for up to a week after the last use. After ten days, the chemicals for of these people will not be visible at the standard of 50 ng/mL threshold. However, in extremely heavy and long-term use cases, users can even test positive for up to 70 days.

Individual Physiology

Every person has a unique physiology and body type. Persons with a high metabolism will process cannabinoids quicker than those with a slow metabolism. Fast metabolisms will rid the body of cannabis metabolites quicker than a slow metabolism.

On average, men also tend to lose traces of marijuana faster than women: this is because physiologically, male bodies contain less fat. With less fat, men’s bodies have less space to accommodate marijuana metabolites than women.

User Lifestyle

Lifestyle choices can be highly influential for the storage time of metabolites in one’s body. If the body has more fat cells as a result of lifestyle, thier body can store more marijuana metabolites, and for longer periods. People who eat a lot of fatty foods and do not exercise will likely store more metabolites than their peers.

Type of Compound

The standard test usually focuses on analyzing THC or THC-COOH. This means that people consuming a cannabis strain dominated by cannabidiol (CBD), or hemp oil, are less likely to test positive in a marijuana test. Hemp oil still contains small amounts of THC, so if you consume extremely large quantities, you may test positive.

Given all these variables that can influence a drug test, the results are often unpredictable and sometimes even surprising. For example:

  • You may test positive, even having stopped smoking marijuana several months ago.
  • You may have stopped smoking and have tested negative in a previous test, but in a new test get a positive result.

How do you get rid of THC in your system?

So if these tests are extremely rigorous and can trace back your consumption month ago, what can you do? The best answer is to take time and a healthy attitude.

Does drinking water help you pass a drug test?

No, water will not help you pass a drug test. The traces of marijuana left in the body are fat-soluble, not water-soluble. This means that though urine can be diluted, in a best-case scenario the user will be asked for a re-test.

The logic: By drinking lots of water, the traces of cannabis in the urine will be diluted by water and will fall below the threshold.

The problem: Drinking too much water dilutes the urine, but that is identifiable in lab testing.

In the best case scenario, your sample will only be rejected, and you will need to redo another test. This will not solve the problem of the drug test.

Additional issues with dilution:

Inefficiency. THC is not water-soluble, so while drinking a lot of water might change the concentration found in urine, it will not eliminate it from the body.

Danger. Drinking too much water can be dangerous. Water poisoning occurs if excessive amounts of water are consumed causing a severe imbalance of electrolytes.

The Best Solution: Exercise

The best option is healthy eating and exercise, in addition to no longer consuming the drug, obviously. The traces of marijuana are stored in the body’s fat cells, so focusing on those cells will help to remove traces of the drug.

Eating healthily. The point is not to suddenly lose weight; the point is to stop consuming fast food, processed food, and overly fatty foods. Consuming small amounts of healthy fat will not be harming to your fat-burning goals.

Exercise. The point of exercising, in the context of drug tests, is to increase your metabolism and burn the fat cells that store cannabinoids. It is important to exercise in a healthy manner – slowly and progressively.

How Long Does Marijuana Stay In Your System?

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