Does Niacin Work to Pass a Drug Test?

Introduction: What is Niacin?

Many detoxers wish to know whether Niacin can help flush toxins such as THC from the body ahead of a drug test and how many niacin pills to take to pass the drug test. Niacin is a form of Vitamin B3 and is also an organic compound.  It is a colorless, hydrophilic compound that is derived from pyridine which is a weakly alkaline liquid. Niacin often features detox products but too much of this substance can result in symptoms such as flushing and sweating.  More serious side effects can result in some cases.

If you wish to detox using niacin pills, a detox product which includes Niacin for a drug test or any detox substance for that matter with the purpose of beating a drug test, first ensure that it is legal to do so in your territory.  Many regions including several U.S. states have made this practice illegal. For some, often niacin pills are used for raising HDL cholesterol levels which is a good form of cholesterol as well as treating pellagra, which is a disease resulting from insufficient levels of Vitamin B3 in a person’s system.  It is also often used to support treatments for high blood pressure.  The body can achieve synthesization of niacin through tryptophan although a deficiency which is the result of malnutrition may cause pellagra symptoms. Using Niacin in an effort to pass drug tests has not yet been proven and is largely dependent on anecdotal reports. Further, it is very possible to overdose on Niacin so make sure that you take a safe dosage. Those with hypertension take low doses over a more extended period of time.

Do not attempt this method if you are 18 or under, pregnant or nursing, have liver or kidney issues, or if you already take supplemental niacin as you can overdose.


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Negative Side Effects of Niacin Pills & Health Risks

Niacin can have a range of potential side-effects.

  • Flushing:

Flushing is the most common side effect reported by users.  How long does flushing last with niacin? Flushing may last from 15 to 30 minutes with niacin pills.

  • Other Mild Side Effects:

Milder consequences of Niacin may include; Insomnia, leg cramps, and mild dizziness.

  • Hepatotoxicity:

High doses, including sustained-release forms over extended timeframes, may lead to hepatotoxicity. Niacin must be taken with caution and within reason. While toxicity requires doses beyond 2000 mg. The daily recommended intake of niacin is 16 mg for men and 14 mg for women.

  • Diabetes:

Another concern is that niacin when taken on a frequent basis to pass a saliva test or to a passing urine drug test, especially if consumed on a daily basis, may lead to an increase in blood sugar which in turn could lead to or worsen pre-existing diabetes.  An individual with diabetes should contemplate using this supplement for detox purposes with great caution.

  • Other Severe Side Effects:

Severe side effects could include but are not limited to; muscle pain, nausea, and vomiting and a severe allergic reaction.  Be sure to check the ingredients of any detox product you are taking to be certain that you are not allergic to any of the ingredients.  Other potential negative consequences of niacin include possible birth defects, visual problems, and blood thinning. Most of these issues are reversible but it is best to avoid suffering these issues in the first place.

When Could & Couldn’t You Use Niacin?

In most cases, it is safe to take Niacin in the appropriate doses.  You should avoid taking Niacin if you are pregnant as it may be harmful to an unborn baby.  You should strongly consider avoiding Niacin for detox purposes if you have diabetes, liver problems, kidney issues, a heart condition, gallbladder issues or stomach ulcers.  Of course, a lack of Niacin in your body can lead to health problems in and of itself but that is applicable to cases of B3 deficiencies and it is a different situation when it comes to detoxing ahead of a urinary drug test. There are substantial risks involved in using the niacin for weed detox.  A case report published by the Hindawi Publishing Corporation discussed an example of acute liver failure in a patient who had suffered niacin toxicity. In the report, the authors presented the “case of an adolescent male who presented to our pediatric intensive care unit (PICU) with acute liver failure (ALF) secondary to niacin toxicity that was ingested as an effort to mask an upcoming drug screen” (Ellsworth, M.A., Anderson, K.R., Hall, D.J., Freese, D.K., Lloyd, R.M. 2014).

How to Use Niacin to Beat a Drug Test

Users trying to cheat on a drug test are looking for a substance or/and product that will have lasting effects through the test period.  Before we discuss the longevity of Niacin’s effects, let’s look at the directions for usage ahead of a drug test;


  1. First, you want to abstain from taking drugs including cannabis for 3-4 days.
  2. Shortly after waking in the morning, take 500 mg of Niacin alongside 2 glasses containing water.  Such a dose is at a level that will likely lead to flushing so be cautious of this fact.
  3. Stay away from fatty foods and urinate on a regular basis.  Niacin will break down fats in order to flush out toxins such as THC.
  4. How much niacin should I take to pass a drug test? Take 500 mg of Niacin every six hours.  Refrain from taking higher doses or doing so more regularly than six hours at a time. This way you will consume at a maximum of 2000 mg in a given 24 hour period.
  5. Drink a substantial but safe amount of water with electrolytes.  Do not consume too much water as this can risk water intoxication which can be fatal.
  6. On the day of the test, take 2 pills with a six-hour period between each pill in the lead up to the test.
  7. Take a B12 pill if your urine is coming out clear.  Don’t go for the test until your piss has turned yellow plus take a small dosage of creatine to ensure that your creatinine levels are right ahead of the test as levels of creatinine that are too low will raise alarm bells with testers.

Many users of this method which is known as the ‘Niacin flush method’ allege that it is effective.  With that said, doses of niacin that are two grams or more for an extended timeline could prove toxic to a person’s liver and it can lead to flushing as well as other uncomfortable side effects.  These side effects can lead to hospitalization.  In yet another case study an example was presented of Niacin toxicity following its use by an individual in an effort to beat an upcoming test (Fayyaz, Rehman, & Upreti, 2018). In this case, the user was hospitalized with vomiting, nausea, and hypoglycemia with possible liver involvement although no liver failure. This individual did recover. However, there is evidence that Niacin (which should be consumed in responsible doses) can cause a temporary state of high ketones leaking and help to clear THC from the body. In recent years, niacin, a form of vitamin B3 is increasingly being advertised on the internet as an effective way to detox drug residues from the body ahead of a drug test. Niacin to pass pee drug tests is widely available near me and you at grocery stores and drug stores.

What Does Niacin Do to THC And Its Metabolites?

How fast can Niacin clean your system? THC and its metabolites persist in fat cells in the body and since niacin can burn fat deposits and speed the natural breakdown of fat, it can, therefore, remove THC from within which can then be flushed out through a person’s urine. Niacin speeds the breakdown of fat. Niacin can also open up blood vessels in fat tissue leading to the release of THC and its metabolites. These are some of the reasons as to why Niacin is deemed an effective way to beat a drug test by many.  Generally, a 500mg niacin pill is used to speed up the process of burning fat inside the body.  Niacin may, as already alluded to, also help with clearing THC from a person’s blood.  After THC metabolites spill out from fat cells, they are processed and removed by the kidneys before being excreted through the urine.  It is vitally important that nothing in excess of 500 mg is used at a time and that intervals no shorter than six hours apart.  An overdose of niacin can result in very harmful side effects on the body and possible death.

According to, “Niacin inhibits fatty acid flux from adipose tissue to liver… and increases hepatic lipid oxidation” (Linder K., Willmann, C., Kantartzis K., Machann, J., Shick, F., Graf, M., Kummerle, S., Haring, H., Fristche, A., Stefan, N., Wagner, R. 2019).  Lipid oxidation is a process inside the body where free radicals take electrons from the lipids (molecules that make up the key components of the function and structure of living cells) of cell membranes which leads to cell damage.  So while niacin can help with the burning of fat, it can have long-term negative effects such as this if taken on a regular basis.

Flush Free Vs. Regular Method

Niacin methods are not limited to using immediate use niacin that causes a flushing sensation some users find uncomfortable.  But, does niacin flush free work to pass a drug test?  There is a wide range of flush free Niacin products available including Flush-Free Niacin.  As with flush-based Niacin, there is no guarantee that it will or will not work.  Non-flush niacin is a type of B3 which often comes as a form of inositol hexanicotinate.  Non-flush niacin is a slow-release treatment.  It may not effectively reduce cholesterol to the degree that flush-based niacin could.  Considering that this method does not help to speed up the burning of fat in the body, it is arguably less likely to support a THC detox than the niacin flush method.  The regular Niacin method is that of the niacin flush method whereby substantial (but safe) levels of urine occur as a result of consuming substantial quantities of water with electrolytes.      This method essentially helps to remove as many toxins as possible while the Niacin itself can remove drug residues by burning fat cells.  Together they use of Niacin and consuming water is seen by many as a strong approach to detoxing the system of drug residues.  Generally, any evidence of high concentrations of niacin will be out of your system in less than 48 hours.  Regular niacin comes in a nicotinic acid form.  This type of niacin will lead to a short-term flushing reaction that could be minimized with a small aspirin dose of about 325 mg (Bank, et al., 2017).  Consuming this form of niacin with non-fatty food has also helped to reduce flushing. You want to avoid fatty foods as this works against the efforts to detox.  This version of niacin works best at reducing bad cholesterol.

How Long Does It Take For Niacin to Clear Your System?

How long does it last?  Niacin should leave your system within only four hours or less of being last consumed.  Niacin metabolites could take up to one to two days before leaving your system in high concentrations.  Trace amounts of Niacin will remain in your system however from everyday foods.  There is a risk that testers could understand that high levels of THC present in a sample if detected.  This is unlikely with that being said since Niacin tends to persist in high levels for a relatively fast period of time.  We do not yet know whether testers plan to detect niacin for passing drug tests.  Since niacin is a common substance found in food, medication, and dietary supplements it is not particularly likely that they will test for niacin and treat it as an illicit substance.

It’s important to know that the half-life of niacin tends to depend on the dose consumed.  If you took a larger dose of niacin it is possible that its half-life could be up to as high as eight hours rather than the generally expected two hour half-time time frame.  Factors that affect how long niacin will stay in your body can include the type and format of the product consumed and factors that are based on the individual.  Individual factors could be your age, genetics, body fat levels (body mass), rate of metabolism, gender and whether or not you are taking any other drugs and if you are, what drugs you are specifically taking.


How Many Milligram Niacin Pills To Use?

The niacin recommended daily allowance is about 16mgs each day.  Alongside its use as a nutritional supplement, niacin is also medically prescribed to treat conditions such as hypercholesterolemia and hyperlipidemia.  Niacin used in low doses tends to lead to few negative side effects but large doses may see niacin cause skin flushing, itching and less often more severe effects. In cases of treating high levels of cholesterol, a range of doses of 50 mg to 3000 mg are used.  For non-prescribed purposes such as supplementing, it is not recommended to go higher than 2000 mg.  While doses of up to 12,000 mg have been studied, serious effects can occur at doses that go above 2000 mg.  It is now the case that those with severely high levels of cholesterol are recommended to first attempt statin drugs before taking doses of niacin higher than 2000 mg.  For treating a B3 deficiency, doses ranging from 300 to 1000 mg are often used. Up to 2 grams have been prescribed for conditions such as the hardening of arteries or for increased energy metabolism.  Such dosages infer that a similar range to improve fat reduction could be effective to lower THC levels.  If a dose of 500 grams of niacin is employed (which should be avoided for sustained and extended-release forms), this could be taken up to four times per day and doses at six-hour intervals.  In turn, the timing of this may be undertaken so that you take 2 doses of niacin prior to your drug test.

Scientific Studies

In 2005, the American Association of Poison Control Centers’ annual report documented a total of 3,109 reports of niacin exposure. In 2006, the Rocky Mountain Poison and Drug Center (RMPDC) based in Denver, Colorado, received many calls regarding severe side effects resulting from the use of niacin for non-medical purposes.  A review of call records from Poison Control indicated a range of niacin abuses in attempts to mask results of a urine drug test even though no scientific proof yet exists that the ingestion of niacin can change a drug test result.  It is not clear if users are attempting to flush THC from their system or hoping the niacin will cause a false negative result as can substances like zinc.

Is Niacin Detectable?

Can Niacin be detected?  As already discussed, niacin is expected to be present in any urine sample in small levels as it is a substance present in food, vitamin supplements and so forth. As stated, we do not yet know whether testers will look at niacin levels in a drug sample.  To our knowledge, this is not yet the case. However aside from initial health reasons, you want to avoid taking too much niacin in case it does reach levels that may raise eyebrows.  Even if this does not result in failing your drug test, it may lead to your test being considered void and you could be asked to take the test again.

Customer Reviews

Positive Reviews:

The following review is about the niacin product from Nature’s Bounty.  While this user as with most appears to have used this product for purposes unrelated to detoxing ahead of a drug test, positive reviews like this reflect that niacin has the desired effects which are relevant to detoxing in order to beat a drug test.  Since this product lowered his lipid levels, that means it burns fat and releases THC from the body.

Another example of a positive review on Amazon for the same product as already mentioned.

This product has 76% five-star ratings, 13% four-star ratings and just 11% that are three-star reviews or less with a mere 3% being one-star reviews. This demonstrates there are a lot of forms of niacin that are convenient to take.

The following response from Reddit was in regard to a question asking whether niacin has helped anyone pass a drug test.  This review was shortened for comprehension;

This user passed his test with only 400 mg of niacin total.  He drank water, which should be taken with electrolytes and possibly a diuretic like a cranberry juice or green tea.  You should also take a 5-gram dose of creatine so that your creatinine levels are in the right range.

Negative Reviews:

It should be noted that the vast majority of reviews for niacin products, in general, were positive and highly positive at that but a handful of negative reviews could be found.  Here is an example of a negative review for Nature’s Bounty niacin pills;

Another example of one of the few negative reviews this product had on Amazon;

These users criticized the taste and the uncomfortable flushing but did not say it was ineffective for passing a drug test.


Thus far, evidence for the effectiveness of niacin to prevent THC being detected for a drug test is anecdotal while having some basis on case reports.  In the case we discussed regarding the patient who had niacin toxicity confessed to overdosing in order to beat a drug test, there was no evidence of drug use present which suggests that this method can work albeit you should never ever attempt to overdose on any substance.  This case might point to the possibility that lower and safer doses can achieve similar results.  Lower doses than were taken in the aforementioned case may very well be effective without leading to harm or overdoses. Unless you have experience in using niacin as a supplement for health reasons, it might be best to stick with dilution methods using B-vitamins and creatine to beat a drug test.  Halting drug use as soon as possible is ultimately one of the best ways to pass a drug test although it may or may not work since THC may be present in your system for 30 days or more.  All in all, you want to ensure that whatever detox approach you take, it is both safe and also legal in your territory to do so.

The exciting thing about the Niacin flush is that users are enthusiastic about it and very much convinced that it works.  They have taken to social media to spread the word, even though they are not selling anything and aren’t making any money from it.  That’s a sure indication that they really believe it works.  It either works by burning fat and releasing THC, or it masks drug use by interfering with the accuracy of the test, or it works as part of a dilution method.  In any case, if you try this method, do so using only OTC doses of niacin.  Good luck.


“How Many Niacin Pills To Take To Pass A Drug Test? Niacin Flush” Daryl Seldon, FV KASA, 2018,

“The Importance of a Proper Niacin Dosage” Sophie, Niacin Flush WordPress, 2012,

“Nature’s Bounty Niacin Flush Free 500mg” Amazon, Amazon, 2020,

“Has niacin helped anyone pass a drug test? If so how much did you take?” Reddit, Reddit, 2020,


  • Dr. Joseph Koyner

    Dr. Joseph Koyner is a practitioner MD. He specializes in Addiction Medicine. He is an alumnus of UCCS. Koyner is working as a medical consultant for 15 years. Currently, Dr. Joseph is working as a self-employed specialist in Los Altos, California.