How Many Niacin Pills To Take To Pass A Drug Test?



Figure 1.

Detoxifiers want to know does niacin flush free work to pass a drug test?  Niacin (nyacin) is commonly used in detox products, despite the fact that too much can cause uncomfortable symptoms like flushing and sweating.  People also want to know how much niacin should I take to pass a drug test?  For those unfamiliar, niacin is a B vitamin.  Niacin pills are used for raising HDL (good) cholesterol and treating pellagra, a disease caused by lack of vitamin B3, aka, niacin.

What is Niacin?

Niacin is a B-vitamin.  It is used to supplement the treatment of high blood pressure in those with cardiovascular diseases.  It is also used to treat pellagra, a disease which can cause skin deformation and dementia due to deficiency of vitamin B3, which is one of niacin’s functions.  The body can synthesize niacin using tryptophan but deficiency caused by malnutrition can cause symptoms of pellagra.  Supplementation with niacin at normal levels can have some side effects.  Flushing is the most often-reported side effect.  How long does flushing last with niacin?  Flushing lasts from 15 to 30 minutes.  Niacin for passing drug tests is controversial because there is not clear evidence that it works, though there are anecdotal reports.  Also, too much niacin can have side effects.  You need to know how fast can niacin clean your system so that you don’t use too much for too long.  For hypertension, users take low doses over longer periods of time.

What are the Side Effects of Niacin for THC Detox?

Niacin pills can have some mild to severe side effects including:

  • Facial Flushing

Facial flushing can last up to 30 minutes after a dose of 500 mg per day of niacin for a drug test.

  • Indigestion
  • Liver Damage

This is a great danger of using niacin for weed detox.  High doses, especially of sustained release forms over long periods can cause hepatoxicity.  This vitamin must be used with care and within reason.  However, toxicity requires doses in excess of 2000 mg.  The daily recommended amount of niacin is 16 mg for men, 14 mg for women.

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  • Diabetes

Using niacin to pass a salvia test or other drug test on a frequent basis, especially daily, can lead to a rise in blood sugar which could aggravate or cause diabetes.  Those with diabetes should consider if they will use this supplement with great care.

  • Other: High doses and sustained release can cause, birth defects, blood thinning, and visual problems.  Most problems are reversible or will improve upon cessation of using niacin to pass a urine drug test.

How Could Niacin Help Pass a Drug Test?

Those looking to pass a drug test want results that last through the testing period.  How long does it last?  Let’s first look at how people attempt to use Niacin to pass a drug test.


  1. Try to abstain for using cannabis or other drugs for three or four days.
  2. Upon awaking, take 500 mg of niacin with two glasses of water. This dose is high enough to cause flushing so be aware.
  3. Avoid fatty foods, urinate a lot. Niacin breaks down fats to flush out THC.
  4. Take 500 mg of niacin every 6 hours. Avoid taking higher doses or more frequently.
  5. Drink a reasonable amount of water with electrolytes, not too much.
  6. On test day, take two pills 6 hours apart before the test.
  7. Take a B12 pill if your urine is clear. Don’t take the test until your urine is yellow.  Also, take a small dose of creatine to make sure creatinine levels are normal for the test.

Users of this method claim it works.  However, doses of niacin 2 grams or greater for extended periods can be toxic to the liver, as well as cause flushing and other uncomfortable symptoms.  It can land you in the hospital.  A case study, currently high in SEO hits, demonstrates a case of niacin toxicity following use in an attempt to pass a drug test (Fayyaz, Rehman, & Upreti, 2018).  The bad news is the user was hospitalized with nausea, vomiting, and hypoglycemia with possible liver involvement but no liver failure, from which he recovered.  The good news is that his tests were negative for any cannabinoids or other drugs, despite admitting he had smoked marijuana daily recently.  He recovered in 3 days.  As dangerous as this approach is, it does appear to have worked for this one user on this one occasion.  It also appears to have worked in the way hypothesized, by causing a temporary state of high ketones leaking and clearing THC.  Niacin to pass urine drug tests is widely available near me and you at drug stores and grocery stores.

What Does Niacin Do To THC?

Niacin tablets are used to help burn fat.  Cannabinoids like THC are stored in the body in fat cells.  The 500mg niacine pill is used to speed up the fat-burning process.  Niacin supplementation is often used to lower cholesterol because of its ability to increase blood flow and speed fat-burning.  A side benefit of this effect appears to be that it also quickly clears the blood of THC.  Once the fat cells spill the THC, the kidneys remove it and it is excreted through the urine.  This is how a niacin flush works.  It is imperative that no more than 500 mg is used and no sooner than every 6 hours.  The side effects can be very damaging if niacin is taken in overdose.


Figure 2.

No Flush Versus Regular Niacin

Regular niacin is in the form of nicotinic acid.  This form of niacin will cause an initial flushing reaction which can be minimized with a small dose of aspirin (325 mg) (Banka, et al., 2017) .  Taking this type of niacin with food can also help reduce flushing.  This type of niacin is best at lowering bad cholesterol.  It can also expand blood vessels, hence, the flushing.

Nicotinamide is another form of niacin.  It is not as strong at lowering cholesterol or expanding blood vessels.  It is able to treat Vitamin B3 deficiency without inducing a troublesome flush.

No flush niacin is a form of B3 which is usually in the form of inositol hexanicotinate.  It is a slow release treatment and produces no flush.  However, it may not be effective at lowering cholesterol.  It may be able to improve insulin sensitivity and treat other conditions.  Since it does not speed fat-burning, it is not ideal for a THC detox.

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

Niacin should be out of your system within just about four hours.  The metabolites of niacin may take between one and two days to leave your system in high concentrations.  You will of course have trace amounts of niacin in your system from everyday foods.  The reason one might want to know if niacin will be detected in your system in high amounts is the danger that testers may wise up to the niacin flush method of trying to beat a drug test for THC and begin testing for high levels of niacin.  While this may be unlikely, it does appear high levels of niacin will leave your system quickly.  However, users will try to have their test done while niacin is still doing the job of flushing THC out of the fat cells, so they will have high levels of niacin in the blood stream when the testing sample is taken.  It is not currently known if test-makers have plans on testing for niacin, but since it is a common dietary supplement, medication, and also an essential nutrient, it is unlikely they will begin testing for it and treating it as an illicit substance.  In any case, evidence of high concentrations will have left the system within two days.

What Dosage to Use?

The recommended daily allowance for niacin is around 16 mg per day.

For the treatment of high cholesterol levels, doses of 50 mg up to 3000 mg are used.  For non-prescribed supplementation, it is not recommended to go above 2000 mg.  Though doses as high as 12,000 mg have been studied, adverse effects may occur at doses above 2000 mg.  It is now recommended that those with dangerously high cholesterol levels first try statin drugs before using a dose of niacin above 2000 mg.

To treat deficiency (pellagra), doses of 300 to 1000 mg are used.  Up to 2 grams have been used also for conditions like hardening of the arteries and for improving energy metabolism.

These dosages suggest that the same range for use to improve fat utilization may be effective to lower THC concentrations.  If a dose of 500 grams of niacin is used (avoid sustained and extended release forms), this can be used up to 4 times in one day and dosed 6 hours apart.  Therefore, the timing may be done so that you have taken 2 doses of niacin before your drug test.

User Discussion


The evidence for the efficacy of niacin at preventing detection of marijuana use is anecdotal and based on case reports, such as the one referenced below dealing with niacin toxicity.  What was interesting about that case report is that although the patient with niacin toxicity admitted to overdosing to beat a drug test, no evidence of drug use was found, suggesting that although it landed him in the hospital, it might have worked to cover up drug use.  Lower doses than this patient used may be effective without producing illness and overdose.

The user discussion at the forums on above show two users expressing skepticism, and one user saying the approach worked for a friend who took 4 capsules over 24 hours, the day before the test.  This is just at 2 grams, which may be safe, especially if taking the normal form, and only on special occasions.  Another approach is to take 2 grams only in the 24 hours before the test, but lesser amounts on the days leading up to the test, to avoid adverse reactions and liver toxicity.

Our opinion is that, unless one has experience in using niacin as a supplement or for health indications, stick with dilution methods with B-vitamins and creatine to pass cannabis drug tests.


Banka, S. S., Thachil, R., Levine, A. R., Lin, H., Kaafarani, H. M., & Lee, J. (2017). Randomized controlled trial of different aspirin regimens for reduction of niacin-induced flushing. American Journal of Health-system Pharmacy, 74(12), 898-903. Retrieved 9 9, 2018, from

Fayyaz, B., Rehman, H. J., & Upreti, S. (2018). Beating the urine drug test – a case report on niacin toxicity. Journal of Community Hospital Internal Medicine Perspectives, 8(2), 73-75. Retrieved 9 8, 2018, from

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