Fraser Horton
Fraser Horton
Last Updated on August 20, 2021

As drug use is increasing drastically around the world, users who have regular workplace drug testing are more worried about getting positive results for cannabis presence on their tests. For that reason, they often turn to detoxing before drug tests, and niacin has become one of the most popular methods for detoxing tetrahydrocannabinol (THC) from the body. 

When users consume cannabis, the THC metabolites bind with the fat cells in the body, therefore the more body fat you have, the longer it takes to detox.

There are different types of drug tests available today, but they all measure the THC levels from the samples taken from the person getting tested.

Previously, we covered if niacin could clean your system from weed, but in this article, we are focussing on how long do you need to take it in order to flush the THC out. Note, however, that we are not encouraging cheating on drug tests. This article is purely for informational purposes only.

What Is Niacin and Why Do People Use It?

Niacin is a form of vitamin B3 that is used as a nutritional supplement. Also known as nicotinic acid, it’s generally used to manage niacin deficiency (pellagra). More often than not, niacin is used in a pill-form and the pills can contain from 50 up to 1000 mg of niacin per pill. Depending on the condition that is treated, a specific dose is prescribed for each patient. 

Niacin works by inhibiting hepatic lipogenesis and triglycerides production and because of that doctors use it as a treatment for patients that suffer from high cholesterol levels. Moreover, niacin is prescribed to patients in order to improve blood flow if they suffer from angina, high blood pressure, and other heart disease risk factors. Since it dilates the blood vessels, people assume that niacin flushes THC out of the system when they know they need to undergo a workplace drug test soon.

Drug Testing in the Workplace

Since the War on Drugs, mandatory drug screenings have been a common occurrence among many companies around the world. As a result of that, many recreational marijuana consumers fear getting positive drug test results and turn to niacin.

If we look into the most common testing methods we’ll see that each individual testing method varies in terms of the time frame in which it has the ability to detect the presence of cannabis:

  • Urinalysis – done by taking a urine sample which can result in a positive test after 5-7 days for moderate marijuana users, and even more than a month for heavy chronic users. This is the most common method of workplace drug testing.
  • Blood test – done by examining a blood sample which can detect THC levels up to a week after cannabis use.
  • Saliva test – has a detection window of up to 72 hours after initial cannabis use.
  • Hair test – has the highest detection period of up to 3 months.

When testing, testers look for the presence of 11-OH-THC (the main active metabolite of tetrahydrocannabinol) and THC-COOH (the second metabolite of THC that’s formed in the human body after cannabis is used).

How to Do a THC Detox Before a Drug Test Using Niacin?

So, let’s get into the subject of how long it takes for niacin to flush the weed out of the body. Firstly let’s say that this method may not work for heavy users who use large amounts of cannabis, but may work for occasional marijuana users.

You can do a THC cleanse by using the following steps:

  1. Stop using drugs until your test and start your 3-4 day niacin flush.
  2. Take 500 mg of niacin every 6 hours leading up to your test accompanied by plenty of water.
  3. On the day of the test, take two pills within 6 hours between them.

It’s important to remember not to consume more than 2 grams of niacin per day, and also take some salt or electrolytes in order to replenish the vitamins lost during the detox. People that do this method also benefit by taking a supplemental dose of creatine in order for the creatine levels to measure correctly on the day of the test. Some people even decide to do a home THC test prior to taking the test at work as a preventive measure.

What Are the Side Effects of Niacin Pills?

According to scientific evidence, low doses of niacin can be beneficial as a treatment for certain diseases, however, large amounts of niacin can result in niacin toxicity as well as other side effects.  The side effects can include skin flushing, itching, skin rashes, vomiting, and tachycardia among other side effects, according to a study done by the Greater Baltimore Medical Center. Furthermore, serious side effects like liver failure can even occur after a single high dose of niacin

Another study done by the CDC in 2006 shows that the effects of niacin range from mild to life-threatening in different people. For that reason, the doses of niacin that are consumed by patients should be prescribed by a licensed physician.

What Else Do People Use?

Apart from niacin, people also turn to other methods of detox. These can include detox drinks and other detox products which are often accompanied by large amounts of water. Some people even use diuretics which speed up urination in order to detox from cannabis, but this method can dilute the urine sample and may arouse suspicion in drug tests. 

Others turn to exercise as a way to burn fat and help the fatty tissues release the stored THC, although this method is ineffective if you are trying to detox your body in a short amount of time. You could also decide to detox naturally, but it may take a longer time for the cannabinoids and their remaining metabolites to exit your system this way.

To Sum It Up

While there isn’t a foolproof way to detox from cannabis, some moderate users may benefit from doing a niacin flush before a drug test. To start the detox, users should stop consuming marijuana until their drug test and start using niacin. Doses of 500mg taken in 6-hour intervals may flush the THC metabolites from the body in time for the drug test to come out clean. Again, we don’t recommend cheating on drug tests as it’s illegal – this article is for educational purposes only.

Along with the niacin pills, users should also supplement with electrolytes and creatine in order to have a urine sample that has normal measures. What’s important to remember is that excessive use of niacin can result in niacin toxicity, as well as liver toxicity and other side effects, and because of that, users may benefit from getting the opinion of a licensed physician before trying this method.


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