How Many Niacin Pills to Take to Pass a Drug Test?

What is Niacin (nyacin)?

Niacin is a form of vitamin B3. It is sometimes called nicotinic acid. The chemical formula is C6H5NO2  It is an essential nutrient.  Food sources rich in niacin include fish like salmon and tuna. B-vitamins like niacin are known to be involved in energy metabolism and many health-conscious people supplement with them.

It is also sometimes used in the form of a tablet to improve blood flow and cholesterol levels. It is the most effective way to raise good HDL cholesterol. Many doctors will prescribe niacin to persons with high blood pressure, high bad cholesterol, angina, or other heart disease risk factors.

Niacin pills are used for:

Niacin is used to improve outcomes in cardiovascular disease and high blood pressure.

It can be used to treat niacin deficiency, a condition called pellagra.  Pellagra can cause neurological dysfunction.  Niacin is also sometimes used in a genetic condition called Hartnup’s disease.  This is a syndrome wherein the body has difficulty absorbing b-vitamins and amino acids like tryptophan, which is an amino acid precursor to niacin.  Extra niacin can prevent pellagra-like skin disease and dementia in Hartnup’s sufferers.

Some people use niacin to try to pass a drug test.  Some evidence suggests niacin can interfere with the accuracy of a drug test.  There is as yet, no smoking gun scientific evidence that niacin can do any such thing.  Many people have claimed in online discussions on drug use forums that they have passed a drug test using niacin supplements.  However, there are risks and side effects of niacin supplementation. See examples of such products in the chart below: Toxin Rid and Mega Clean.


Toxin Rid

  • Three-part detoxification system with pre-rid tablets, liquid detox, and dietary fiber
  • Specifically designed for people with HEAVY toxin exposure
  • Starts working as fast as one hour
  • Rids your blood, urine, and saliva of unwanted drug toxins
  • 100% money-back guarantee
See Deal →

Mega Clean + PreCleanse Pills

  • Minimizes your toxin levels in one hour, effective for up to five hours with the maximum effect at three hours
See Deal →

Niacin for Passing Drug Tests Side Effects

Side Effect
Mild – Facial FlushingIf you take a 50 mg to 500 mg dose of niacin pills per day, you may turn red in the face.  How long does flushing last with niacin?  It will last for up to 30 minutes.  Some users describe the feeling as uncomfortable.  Some aren’t bothered by it.  Others describe it as a burning pain and seek out forms of niacin which will not cause a flush.
Moderate – Indigestion, nausea, vomitingAny dose of niacin to pass a urine drug test can cause a feeling of stomach discomfort.  This can lead to nausea and vomiting.
Severe – Liver damageDoses of niacin for a drug test above 2 grams per day (2,000 mg) can result in liver damage which can be life-threatening.  The daily intake of niacin needed for normal function is about 14 mg for women and 16 mg for men, from food sources.  Taking large doses at once can cause acute liver failure which can be a life-threatening condition.
Severe – DiabetesDaily doses of high-dose niacin for weed detox can cause or aggravate diabetes by causing insulin resistance.  It may raise blood sugar which can damage organs like the eyes.
Severe Side Effects of High Dose long-term niacin therapy: list
  • macular edema,
  • ischemic stroke,
  • insulin resistance,
  • hypotension (low blood pressure, dizziness, fainting),
  • hepatitis,
  • hepatic dysfunction
  • heartburn,
  • glucose intolerance
  • fatigue,
  • cerebral hemorrhage,
  • blurred or impaired vision
  • acute liver failure
  • gastrointestinal ulcer
  • diabetes,
  • dyspepsia,
  • diarrhea

A 2018 report in the Journal of Community Hospital Internal Medicine Perspectives listed several cases of toxic reactions to the ingestion of large doses of niacin in an attempt to beat a drug test (Fayyaz, Rehman and Upreti).  Metabolic acidosis is a frequent result.  This is a life-threatening condition most often associated with poorly controlled diabetes.  As the liver is unable to process carbohydrates and fats normally due to toxicity caused by niacin overdose, the body begins to become overly acidic.

Lactic acid also builds up as the body tries to use back up energy sources.  Ketone bodies build up.  The effect is highly acidic blood chemistry.  Due to these risks, large doses of niacin are not recommended.  Also, extended-release forms of niacin are not recommended because they do not give the liver a chance to recover from processing niacin.

Another risk is acute renal failure.  As these acids build up in the blood, it is the job of the kidneys to remove all of these waste products.  The kidneys are overloaded and begin to fail.  At this point, one can develop multiple organ failure.

As you can see, the victims of these illnesses recovered from very serious conditions after hospitalization for taking large doses of niacin in an attempt to beat a drug test.  Many more cases were probably not reported.  Therefore, don’t be stupid.  Do not take large doses of this vitamin.

Keep your liver happy.

How Much Niacin Should I Take to Pass a Drug Test?

Using niacin to pass a drug test is an approach that has somewhat fallen out of favor. As FMA Health claims, this is because there are companies that produce detox drinks and substitute urines which appear to be safer than trying to use high dose niacin.  The most immediate risk is an acute liver failure which can occur after a single use of a high dose of niacin and can be deadly.

Niacin is believed to work by causing the body to go into overdrive in burning fat cells.  This may release extra amounts of THC from the cells such that when tested, there is a reduced amount in the urine.  THC is fat-soluble and therefore hangs around in fat cells for as long as 30 days before coming out into the bloodstream and finally into the urine.  When you burn fat, THC metabolites are steadily released.  People attempt to use niacin to accelerate this process and cause the THC to come out faster so that they can flush it out of their system before a drug test.

Niacin will also open the blood vessels to allow for the elimination of the excess THC.  However, an article in a scientific journal from 2005 suggests this is not how it works.  In fact, the article claims that niacin most likely simply masks the presence of drugs by decreasing the reliability of the urine drug test (The Real Score between Niacin and Drug Tests, 2005).  It is possible that niacin works in both ways when it is successful in masking drug use.

A 2005 report from the American Association of Poison Control Centers cited 3,109 toxic exposures to niacin in that year.  Many of those who took the supplement in an attempt to beat a drug test was around the age of 18.  We do not recommend anyone under 18 use this supplement for any non-medically supervised purpose.  Also, higher doses of niacin will sometimes require a prescription.

The good news is no deaths were reported; however serious health issues did occur, from which most or all subjects recover.  It is not clear if using niacin will help to mask the use of drugs other than THC.  It is thought to work by helping to flush the body of fat-soluble drugs only.  However, it may reduce the reliability of drug tests for other substances.

Directions for THC Detox

  1. As soon as you know you have a marijuana lab test, cease using weed.
  2. As you wake, take a 500 mg tablet of niacin. Drink two glasses of water.
  3. 6 hours later, take another 500 mg. You want to separate your doses in time to avoid liver toxicity.
  4. Take a vitamin b 12 pills and a 2-gram dose of creatine monohydrate.
  5. Go take your urine drug test. This will not help you pass a saliva test.  It is for urine tests only.
  6. How fast can niacin clean your system? How long does it last?  Expect it to work after one hour and for up to 5 hours.  Niacin is available at any department store or pharmacy near me and you.  If you try this method, let us know your results and side effects.

Flush Free Vs Regular method

The method described above uses regular niacin.  If you cannot tolerate the flush, a low dose of aspirin can prevent discomfort from flushing.  Does niacin flush free work to pass a drug test?  There is a form called flush free niacin which is preferred by those who cannot tolerate the niacin flush.

Regular niacin (nicotinic acid) is superior at lowering cholesterol and widening blood vessels.  The drawback is simply the flushing.  To be fair, flushing while taking a drug test could make you feel like you look suspicious.  However, in most places, taking supplemental niacin cannot be made illegal, unless you take mega doses which would require a prescription.  Niacin is a natural component of food and supplemental niacin is not distinguishable for dietary niacin when in the form of nicotinic acid. Keep reading FMAHealth to get know more about it.

Non-flush niacin comes in the form of inositol hexanicotinate and other slow and extended-release forms.  This form does not lower cholesterol or burn fat as well so it may be less effective at reducing the detection of THC in the urine.  The Harvard News-letter in March 2010 warned against using inositol hexanicotinate as it does not convert to nicotinic acid and therefore provides no niacin.

Also, extended-release niacin over-exposes the liver to niacin and is therefore not good for liver function.  These forms may be ineffective and/or present extra risk.  The prescription drug Niaspan is an intermediate release form that reduces flush and gives the liver a break.

How long does it take for niacin to clear your system?  Regular niacin stays in your system for 2 to 4 hours.  Niaspan is in your system up to 12 hours and extended-release niacin is in your system all day.


Toxin Rid

  • Three-part detoxification system with pre-rid tablets, liquid detox, and dietary fiber
  • Specifically designed for people with HEAVY toxin exposure
  • Starts working as fast as one hour
  • Rids your blood, urine, and saliva of unwanted drug toxins
  • 100% money-back guarantee
See Deal →

Mega Clean + PreCleanse Pills

  • Minimizes your toxin levels in one hour, effective for up to five hours with the maximum effect at three hours
See Deal →

Niacin is not detectable as an adulterant in drug tests.

Customer reviews

Reddit: a positive review

This user from Reddit claims niacin does not work by burning fat and releasing THC, nor is it a masking agent that decreases the reliability of the drug test.  It simply works like other b-vitamins which add yellow color to the urine while drinking lots of water causes the drug metabolites to be dilute.  This is a possibility.

Reddit, positive review

This user gives us a hint as to what is so bad about the flush.  Apparently, it feels like one’s skin is burning to some people.  He appears to have used it as part of a dilution method, as well as trying to burn the fat cells to get the THC out.

Reddit, negative review

It did not work for this user.  He/she decided to opt for a detox drink, which worked.

Reddit user, positive review

This user got good results.  We can confirm that most home drug tests are just as accurate as of the drug tests used on a job site.

Conclusion: Does Niacin Work for a drug test?

We have not found scientific evidence that niacin will help you beat a drug test.  The closest to scientific evidence we have found is that one of these people who came into the hospital gravely ill from a niacin overdose actually tested negative for drugs.  However, that is just a case report and also, he was very sick so it’s questionable if it were worth it even if he somehow passed his drug test. You may use niacin pills or ready-to-use pills, such as Toxin Rid .

Niacin may work by dilution if you drink a lot of water with it.  However, you would need to also take a normal supplemental dose of creatine so that your creatinine levels measure correctly and your sample doesn’t come back as dilute.  Lastly, you should take some salt or electrolytes so that the specific gravity of your sample comes out correctly.

Detox Drinks

The most popular alternative to niacin pills to pass a drug test is that of detox drinks.  There are many detox drinks available online, in head shops, and even in gas stations.  Mega Clean Detox is a popular and trusted brand.  Detox drinks generally contain b-vitamins (usually to the exclusion of niacin due to the give-away flushing and possibility of overdose), creatine to raise creatinine content, diuretic herbs to increase urine output, and electrolytes to get the right specific gravity and also to avoid symptoms of water intoxication. Detox drinks have a better chance of working than that of a niacin flush.  However, detox drinks are not legal in every state. Here are some laws about detox products.

First is a federal law.  It is against federal law to attempt to defraud the United States government.  You can be charged with this if you try to beat a drug test for a government position and get caught.  Also, if you are caught trying to beat a federal court drug test, you could be charged. The original makers of The Whizzinator fake penis and Powdered Urine kit were charged, convicted, and imprisoned under this law.  However, we have found no cases of customers being convicted for using the product.  One man was arrested for selling a detox product to an undercover agent at a gas station.

In three states, it is illegal to sell detox products.  These states are New Jersey, Kentucky, and Florida.

In two states, it is not legal to deliver or produce a detox product.  These states are Texas and Louisiana.
Nine states ban the selling of adulterants. This is where things get tricky.  If for some reason they were really suspicious of you and they discovered that you had tried to flush with niacin, for example, because you had to admit it at the hospital, theoretically, they could charge you will using an illegal adulterant.  However, this is unlikely and has probably never happened. These nine states are:

  1. South Carolina
  2. Pennsylvania
  3. Oklahoma
  4. North Carolina
  5. Virginia
  6. Nebraska
  7. Maryland
  8. Illinois
  9. Arkansas

Synthetic Urine

Synthetic urine is fake urine that is made in a factory to fully mimic human urine in order to calibrate urine testing equipment.  Companies discovered they could also sell this urine to people who are trying to beat a drug test and a new industry was born. Quick Fix Urine is arguably the leader in this industry.  Powdered Urine kits are available online, at head shops, and at gas stations. They are not all created equal.  Check our website for the best reviews of synthetic urine available on the web.


Substitution is another approach to beating a drug test preferred over niacin pills.  Some people swear they will never use any other method.  Online people often advise sourcing your urine from a child, one not on ADHD meds, as the only way to be sure the person has taken no drugs.  Obviously, asking children for fresh urine could get you in legal trouble so use your own common sense and take your own risks.

Anyhow, in this method, what people do is ask a friend for a urine sample, being absolutely certain that friend uses no drugs, uses no medications, uses no herbs (herbs like kratom are sometimes tested for by pain management clinics to make sure you’re only taking their poison, not benign herbs), and has consumed no poppy seed buns.  Yes, you will test positive for opiates if you have recently consumed poppy seed buns, muffins, or tea.  Then, you have to keep the urine body temperature by using a hand warmer or strapping it close to the body.

You have to smuggle it into the testing center and submit it.  If you are not supervised, you can just store it in a condom and put it in the sample cup.  If you are observed, however, you may need to produce a fake penis filled with warm, body temperature substituted urine.  Products like The Whizzinator or Monkey Dong provide skin-tone matched fake penises which you can use to submit a sample under observation.  If you cannot use niacin pills due to ambiguous safety or effectiveness, you might choose one of these proven methods to protect your privacy, where legal only.


Fayyaz, Beenish, Hafiz J. Rehman and Sunita Upreti. “Beating the urine drug test – a case report on niacin toxicity.” Journal of Community Hospital Internal Medicine Perspectives 8.2 (2018): 73-75. 28 1 2020.

The Real Score between Niacin and Drug Tests, 2005. n.d. 28 1 2020.


  • Carolyn Gaughan

    Carolyn Gaughan is an ex-executive vice president of the Kansas Academy of Family Physicians and represents the state associations of the American Academy of Family Physicians and the American College of Osteopathic Family Physicians.