Can you pass a drug test with niacin?

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When it comes to using niacin to flush out THC metabolites from the system, supportive evidence is scanty and questionable.

Nonetheless, we shall review the science behind the myths and possible arguments on the effectiveness of niacin in helping one ace a drug test.

Warning: Hundreds of mild to life-threatening cases are reported each year where drug abusers end up being hospitalized for niacin toxicity.

How to use Niacin to flush out THC

Niacin to pass a drug test


For those who propagate this theory, they recommend using this method the following way:

  • Consume 500mg Niacin with 2 glasses of water
  • Drink some coffee that will help you to urinate a lot
  • Avoid fatty food
  • Take 500mg of Niacin every 6 hours
  • Drink as much as possible

On the day of the test

  • Take 1000mg of Niacin with 2 large glasses of water
  • Drink 1l of water each hour
  • Urinate as many times as possible
  • 1-2 hours before the drug test take B12 pill

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What’s Wrong With This Method

On careful scrutiny, this appears to be a dilution method. And like other dilution methods, you may need to take further precautions to avoid having your results canceled.

Dilution methods work by increasing urine volume and diluting the concentration of compounds in urine. But if you overdo this the whole composition of your urine including the color will change.

To further cheat the system, you will need to take vitamin B12 to give your urine a yellow color. You will also need to take some creatinine to increase the specific gravity of your urine.

Dilution methods have helped a few people pass drug tests, especially when extra precaution has been taken to mask the diluteness of the urine.

However, chances are high that this method may not work.

Why do people use niacin to flush out drugs from the system

When preparing to pass an upcoming drug test, you may be desperate to try anything to ensure that you get a clean record.

However, you need to be cautious so as not to be misled by myths peddled on the web.

Niacin has been touted as an effective way to eliminate THC and its metabolites from the body.

Here are a number of myths that try to explain this theory:

Myth 1: Niacin is able to detoxify the liver.

THC is broken down in the liver into its metabolites which are then transported to the bloodstream, brain, and other organs.

Detoxification is the process by which toxins are removed from the body by being broken down and excreted through urine, saliva, sweat, perspiration, and stool.

If niacin helps in detoxification, then it can speed up the elimination of THC and its metabolites from the body.

Detoxifiers normally work by speeding up the release of toxins from the body and this usually happens in the liver.

Niacin is thought to promote detoxification in the liver. However, there is no scientific evidence to back this claim.

What is known is that niacin in high doses may cause liver toxicity and probably interfere with the breakdown of other drugs in the liver.

Myth 2: Niacin promotes lipolysis

THC is lipophilic meaning that it binds to fat.

Niacin breaks down fat to release THC metabolites that have been stored in the fat.

This theory is based on this fact; niacin will speed up the breakdown of fats so that THC can be released from the fat cells and be excreted.

Niacin helps in breaking down fat from foods that have been consumed; however, it does not help in breaking down fat that has been stored in adipose cells.

This means that niacin plays no role in breaking down fat cells that are holding THC metabolites.

Myth 3: Niacin causes flushing

Flushing happens when blood vessels dilate to increase blood flow.

This theory assumes that when blood vessels dilate they will be able to push out THC out of the body faster.

It also assumes that niacin will cause an increase in blood pressure that will speed up the removal of THC from the body.

Niacin causes increased blood pressure and vasodilatation in blood capillaries. When this happens, THC and its metabolites are released from the fat cells into the circulation from where they will be excreted through the kidneys.

One study revealed that niacin does not affect blood pressure in healthy patients.

Another study also revealed that niacin does not cause vasodilation in capillaries in fat cells as it does in skin capillaries.

In the event that niacin caused vasodilation in fat cells, this would have little to no effect on a drug test. As much as THC is stored in fat cells, it is not trapped in fat cells.

THC is able to move freely between blood capillaries and fat cells to achieve equilibrium. When the blood is depleted of THC, THC will be released from the fat cells and vice versa applies.

There is no evidence to prove that niacin can interfere with this equilibrium.

Myth 4: Niacin inhibits lipolysis.

This theory contradicts myth 1. THC is stored in fat cells.

This theory assumes that niacin can reduce the breakdown of fat cells hence there will be less THC in circulation.

There is no scientific evidence to back the claim that niacin inhibits lipolysis.

But should this happen, it may still not be able to influence the results of a drug test. By reducing the rate of lipolysis, there will be less THC in the bloodstream.

But remember that the equilibrium has to be maintained between the fat cells and the bloodstream.

THC and its metabolites move freely between the bloodstream and the fat cells and it will be hard to fool this system by reducing the amount of THC held in fat cells.

The Risks

Apart from these theories being unsubstantiated, there are a lot of risks associated with consuming excessive amounts of niacin.

A study conducted by the children’s hospital of Philadelphia reported two life-threatening cases of niacin intoxication. Two patients suffered from the adverse reaction on the skin while another case reported neutrophilia.

Remember that an adult requires up to 18mg of nicotine on a daily basis. Doses exceeding 1000 mg per day may cause toxicity to the liver and other organs.

Another study by the University of Arizona reported metabolic acidosis and hypoglycemia in a teenager who had attempted to mask THC by using niacin tablets. The 16-year old ingested 13 grams of niacin in one sitting.

Soon after he experienced hypoglycemia, acidosis, transaminitis, and coagulopathy and had to be treated with bicarbonate infusion to reverse the symptoms.

While yet another 17-year-old patient attempted to use niacin to pass a drug test. The patient was able to recover fully, however, he stood the risk of facing acute liver damage.

Better ways to pass a drug test

Niacin may not be the ideal way to remove THC and its metabolites from your body so that you can pass a drug test.

However, there are other safer and more effective ways to eliminate THC from your system.

Avoid taking weed one month before the test

If you are a new or occasional user, THC may last in your system for up to seven days.

On the other end of the spectrum, the chronic user may have THC persist in their system for between one month to two months.

Just to be on the safe side, it is advisable to stop taking the drug one month to the test.

Consider the dilution method

As discussed above, dilution methods target to dilute the concentration of THC in the urine.

As much as this may not work for everyone, it is a method worth trying. When you take plenty of fluids and are forced to pee regularly, you may test negative for drug tests.

This method involves taking lots of fluids to reduce the concentration of the urine.

But after achieving this you will need to take vitamin B12 to add color to the urine.

You might also consider taking creatinine to increase the specific gravity of the urine.

If this works you may be able to submit your urine sample without it looking too suspicious for a normal urine sample. Most drug tests will detect THC levels up to 50 ng/Ml.

Use cranberry juice

Cranberry juice is known for its detoxifying abilities. It works as a diuretic meaning that it will make you pee a lot.

As mentioned earlier, peeing may help in reducing the concentration of THC metabolites in urine.

However, you will need to mask the effects of dilution in the urine.

Cranberry juice is also known to alter the pH of urine. This may alarm the lab people of possible interference with the samples.


Exercise is a natural way to stimulate lipolysis. As much as this may be encouraging to hear, exercise may not be the ultimate solution.

It will help in breaking down fat cells to release THC into the bloodstream; however, this method cannot be a quick fix for passing a drug test.

What is Niacin

Niacin is a water-soluble vitamin that is available in a number of foods such as ground beef, pork, anchovies, turkey, salmon, peanuts, avocado, mushrooms, brown rice and wheat among others.

Most people do not require niacin supplements, especially when they are consuming a normal varied diet.

The following are the recommended daily dosages of niacin:

  • Men: 16 mg/day
  • Women: 14 mg/day
  • Pregnant women: 18mg/day
  • Children: 2-12mg/day

The body needs niacin to perform the following functions:

  • Break down fats (lipolysis)
  • Lowers bad cholesterol levels
  • Increase good cholesterol levels
  • Reduce the risk of heart attacks
  • Treat type 1 diabetes
  • Improve circulation in the skin and protect the skin from harmful sun rays

When you lack adequate amounts of niacin, you are likely to suffer from pellagra. Pellagra presents with symptoms such as dermatitis, diarrhea, and mental disturbance.

Other symptoms of niacin deficiency include fatigue, depression, memory loss, and skin problems. Most people are able to get the recommended dosages of niacin from their normal diet.

However, some people suffer from niacin deficiency and may need to supplement.

Should you suspect that you are suffering from niacin deficiency, do not be tempted to prescribe for yourself over the counter niacin pills. In excessive amounts, niacin can be harmful to the body.

Symptoms of niacin overdose include flushing, stomach irritation, liver toxicity, and blurred vision. These symptoms are worsened when you have underlying diseases such as diabetes, hypertension and heart disease.

In addition, niacin interacts with other drugs such as blood thinners, diabetes medication, and some herbal supplements.

This interaction will further complicate the adverse effects.


As it is, there are a couple of ways that you can use to “cheat” a drug test.

However, niacin is not among the tops methods. In case you choose to go ahead and use niacin, you should consider consulting with your physician so that they can rule out any underlying reason why this method may work against you in the long run.

Given the risk for toxicity and adverse effects, it is better to try other safer alternatives.


How To Use Niacin To Pass A Drug Test?

Internet sources claim that you should take 1000mg of Niacin at the day of the test and continue with 1l/hour water regimen

How Many Niacin Pills To Pass A Drug Test?

1000mg is a 2 niacin pills at the day of the test and up to 4 pills per day for several days before the test. We don’t recommend it. Niacin doesn’t work for passing a drug test and can cause liver damage.

Where To Buy Niacin For A Drug Test?

Niacin is over the counter drug, so you can buy it in any pharmacy store. Or online on websites like iherb and gnc.

How Long Before A Drug Test Should I Take Niacin?

You should take two 500mg pills of Niacin 3 hours before the test and then continue to drink 1l of water every hour.

Daniel Miller
Daniel Miller

Hey there! I'm Daniel. My research into cannabis shows how cannabis affects health, including how cannabinoids can be used in the treatment of various diseases.

Click Here to Leave a Comment Below 53 comments
Shawn - February 22, 2017

What is the best fast cleaning solution for Meth

    Anonymous - March 12, 2017

    How about, don’t do Meth? This is a cannabis board, not a druggie meth head board. Get your shit together and stop tweaking…

    Anonymous - July 23, 2017

    This might be late, but it does detoxify you from meth. It gets everything out & you are clean after. I hope you’re well now!

    Barbie W - February 2, 2018

    Albuterol Inhaler gives a false positive result.

Diane - March 13, 2017

Omg, you guys are so weak.. just help the girl or shut the hell up if you don’t know. Her drug of choice is not your concern… especially if you are not trying to help her… furthermore .. I have learned that all drugs other than WEED are not in the system very long.. this should help if you take two 500mg a day (1 in the morning and 1 at night) or 4 – 250mg spaced out through the day (2 in the morning and two at night). I’m using it for marijuana. I’m currently on day 5.. I been smoking for almost 6 years consistently and heavily so I would think it would take longer time for me .. I will update and let u all know if it worked. p.s. I haven’t smoked in 3 weeks that should help some.
good luck

    Jay - March 13, 2017

    How long did it take you to get cleaned?

    Mike - June 22, 2017

    It works. I took about 5 pills in 48 hours back In 2016 for a job now I am doing it again.

Ramona - March 16, 2017

I have taken niacin for 5 days, 5 pills 3 times a day. Tomorrow morning I will go drop. Plenty of water and vinegar as well. My urine is the same color as the toilet water. Am I clean from crack?

    taylor - March 22, 2017

    Did it work?

    JJ - March 11, 2018

    If you drink plenty of water and stay active you should be clean within 4 days I’m 5.6 147 pounds and smoked over a g of hard I bought a 24 case of water and constantly drank water and stayed active and I was clean in 4 days but everyone is different and you don’t wanna pee straight up water at your urine screen if its for probation it’s an automatic fail in most places take a b12. Or cranberry pill it will add color to your urine. This has always worked for me with cocaine and opiate use.

Drew - March 26, 2017

Trying to get clean to join the military will this shorten the time is take for my body to be clear of weed?

    John Smith - March 31, 2017

    Use it in combination with the fast THC detox drink. Get the extra strength fruit punch flavor. Down the whole bottle, the morning of the test fills the bottle with water and down that too. Piss at least 5 or 6 times, and the color of your urine should look like yellow Gatorade.

Lauren - April 22, 2017

I haven’t done any hard drugs lately but I’ve taken pills (Adderal) and I get tested weekly so I’m going to try Niacin and see if it works or not? Question for people taking it? I got mine over the counter and they’re 100 mg tablets and I keep reading to take 500mg at a time so should I take 5 of the pills at once?

    Anonymous - March 26, 2018

    Yeah don’t take more than that tho

Dane - May 19, 2017

I had a random drug test I had to take in 3 days one time and I smoked the day before I found out and I’ve been taking 5 100 mg pills a night and drinking cranberry juice all day and then I passed

Shisty - August 8, 2017

Smoke a blunt on the way to see my PO to take a drug screen. Popped 12 100mg of niacin wen got off the bus in front of PO office. Went across the street brought and down a 32 oz bottle of Gatorade. Went across the street to PO office 3rd floor, got off elevator drunk lots of water from the water fountain. Pissed 3 times before took the test and passed. Body burned and itched a lot for bout 30 min but passed.

    Kylie Wilson
    Kylie Wilson - November 28, 2018

    That’s because you consumed a lot of water and diluted your urine;)

Charles - August 19, 2017

I have a drug test on Monday, I’m given a second chance to do it again with supervision, I’m wondering if niacin works or not cause I really want the job. I had to stop for almost 30 days(27 days to be exact) and my due day is on Tuesday the 22. Please help.
Please give me the step by step on taking niacin

Vanessa - August 29, 2017

I smoked Sunday, Monday I found out I had a drug test Wednesday, so Monday I took 500mg niacin in the morning and at night. Planning on doing the same Tuesday and Wednesday I’ll only get a chance to take one, let’s see how this goes… I’ll keep you guys posted.

Vanichi - September 3, 2017

I had to take a hair sample test been smoking weed for a long time! I took 6 Niacin pills on empty stomach threw up! Tried it again the actual drug test day will it work for hair? Please help really need this job!

    Anonymous - September 5, 2017

    It won’t work for hair, unfortunately only works for an urinalysis test.

      Anonymous - March 10, 2018

      How long will it take to get weed out of my body taking these pill?

    Star - December 10, 2017

    Did you get locked up?

TT - October 13, 2017

Is there something (a different pill) that’s stronger then Niacin (pill form) and that works quicker than Niacin to take to get rid of THC but will still keep my pain meds in my system?

Josh - October 17, 2017

I haven’t smoked in three weeks. I’ve been taking niacin every day taking 3 pills a day that’s 1500 mg. I’m still not passing in home tests. All I drink is water.

    Doug - January 24, 2018


    You need to make sure that the niacin you are taking is not flush free!! Everyone on these forums needs to know that there are niacin pills that can be purchased from grocery stores and drug stores that do NOT contain the supplements found in niacin that cause its flushing effects.

    A great way to know whether or not you are using a “flush free” version of niacin is with a 500mg pill, two 250mg pills, or 5 100mg pills, you should certainly feel itchy, your face and skin may start to turn pink/red, and you may feel a type of dizziness and somewhat of a head high in my case. I smoked weed and when I flushed with niacin, I felt a bit of a head high similar to the feeling of being high from THC.

    Also, when flushing with niacin, my recommendation is that you take no more than a combined total of 500mg at a time. You should have an empty stomach when doing this, and drink LOTS of water. Do not kill yourself with water, but drink as much as you comfortably can. The biggest thing is drink water consistently, don’t try to down a gallon at a time. You should be needing to urinate several times throughout the day.

    I would advise that you do not eat for 3 hours after taking niacin while drinking plenty of water to help the niacin to flush out your system. After 3 hours, eat something light so your body is not starving and so your content. Wait 1 hour after eating before using another niacin and repeat the process. You can feel the effects of niacin become less potent as your body has fewer toxins to release.

    IMPORTANT: I am not a doctor, nor certified in any medical practice. Do this at your own risk, I do not take any responsibility for the aforementioned language above!

Meg - December 13, 2017

I’ve been smoking the past month and I might get drug tested in six days by my Po what can I do to get weed out of my system faster

Anonymous - January 15, 2018

I’ve smoked for about 6 years heavily. Just stop today took my first nice and wondering how long it would take to pass a drug test. It’s really important for my kids I only smoked weed I have an eating disorder. So I smoke to eat but I can’t anymore I need to know what to do. Specify you say that you take one in the morning and one at 9 I got the 500 mg I’m going to try to get some cranberry juice

Anonymous - January 24, 2018

I have to test next week Wednesday . I started niacin yesterday Monday. Taking cranberry pills and plenty of water. Will I pass?

    Kylie Wilson
    Kylie Wilson - January 24, 2018

    Most likely you will pass, but your results may come diluted, so you need also to take creatine and B12 to make it look normal.

Zach - January 29, 2018

I am trying to pass a possible test five days after coke I started taking niacin 3 days before test everybody says 3 Fay’s for coke I don’t trust, does niacin work for coke?

    Mike - February 23, 2018

    Coke is out of your system in like 2 days anyway I thought?

      Anonymous - May 30, 2018

      Depends on how much and how long you have consumed

Anonymous - April 3, 2018

I have failed a drug test using the niacin method… a few years ago I was applying for a job and I did a 5-day detox with it. Took 6 (500 milligrams) pills a day Then stopped taking the niacin and tried to cleanse naturally for 30 days. I Still failed the drug test. Now I’m looking to get a new job that requires a piss test…

I’m skeptical but trying the niacin method again. I have all my bets covered this time though… I Have been taking large doses of niacin every day for the past two weeks… bought an at home drug test to take before my actual test and if I still fail… I bought synthetic urine to substitute… I am skeptical about niacin but never once have I failed a drug test using synthetic urine so hopefully, everything plays out the way it should.

Anonymous - April 3, 2018

Niacin is a gamble. I have both passed and failed before trying this method. The best thing you can do is to try the niacin method ( because passing naturally is way less stressful than risking detox drinks or keeping fake piss at proper temperatures before your test) but also get an at home drug test on the day of the test to test yourself!

If You fail then use synthetic urine. I have never failed once with synthetic urine but like I said though that carries a risk itself because keeping it warm while you wait in a clinic can be stressful! I have a drug test coming up for a new job hopefully me taking a bunch of niacin for the last two weeks will allow me to pass it’s so stupid they’re still testing for weed anyways… like smoking weed doesn’t make you an irresponsible criminal. -.-

    Anonymous - April 10, 2018

    Update: I’m probably going to be drug tested tomorrow for sure for this job so I took a at home drug test. Three weeks of not smoking weed and 32,000 milligrams of niacin thruout a three week span (not flush free) didn’t make me pass an at home drug test. Don’t take chances with this. I’m sorry to say I am very disappointed looks like quick fix plus is the best bet after all

JD - April 5, 2018

I smoked pot for about a month and I have drug test 5days from now. I took detox drink and niacin will I pass or fail?

Avatar - April 25, 2018

Why does flush free niacin not work?

sheba - April 29, 2018

I have the 750mg, niacin, and i have a frug test by the end of may, i only have like 6 or 7 niacins, if i start now will i ve clean? By June?

    Anonymous - May 9, 2018

    Yes I think you will be clean just take the niacin but down cranberry juice, exercise and drink lots of water. The night before load on a bunch of food and the morning of don’t let yourself shed fat in the couple of days before and buy an at home drug test if there is a faint line in the control line you are good

Carolina - June 21, 2018

I have a drug test friday, last time i smoked was Saturday night. I just got some niacin pills been taking them since Wednesday. Can I pass?

Anonymous - July 27, 2018

I have a drug test in 2 hrs. I take 2 500mg every hour all night and it works

Ladybug - September 9, 2018

My last puff of weed was 30 mins ago…I have been smoking “loud” for years. My job never drug tested. Recently I lost my job and now I’m back out in the world doing interviews. I have 2 interviews this week coming up. I have Niacin 500mg…think I can clean up by Wednesday if i start tomorrow? If so how many should i take?

    Zach - October 3, 2018

    3 500 mg the morning of suspected screen

Zach - October 3, 2018

I have a cousin who swears by it and passed his pisses at his p.o. for 2 years. Always complained of being itchy an red like rash. But he would take em in the morning. Hed take 3 and drink and pee as much as possible before he went. He always said 3 pills 3 bottles of water 3 pisses . The 4th piss is clean. He is off probation now. Never failed. He smoked and done pills (perks, addis, neuroton, box. I stand by the niacin method for ive seen it first hand. However try to stop pills within 24 hrs of test. And stop smoking 3 to 4 days before. And your all good!!!

Dicky - January 9, 2019

Had a drug test one morning took 3 niacin pills (don’t believe they were over the counter) that’s why y’all are having problems, over the counter niacin isn’t the same, drunk 1 1/2 bottles of water, took drug test 30-45 mins later and passed

Unknown - February 28, 2019

I smoked yesterday and have took 1500mg of nician will I b clean by 2 pm 2day I have a drug test I’m 5’4 175

Linux Lewis - July 24, 2019

Your weight and how often you have been smoking has a lot to do with it.

If you are overweight and you smoke often you have greatly decreased your chances of passing a drug test regardless if you drink a ton of water or consume niacin.

If you have moderate weight and only smoke once or twice a week then you have a good chance of passing a drug test while consuming niacin.

THC is stored in your fat so if you are overweight and smoke weed then you have a good number of fat cells saturated with thc..this is the bottom line.

If you are overweight then do not risk it just buy the fake piss. If you are medium weight or thin there is a high chance you can pass with abstinence, water, and niacin.

One thing you have to keep in consideration when you are on these types of forums is its like the county jail…no one is going to tell you the truth of what really happened to land you in jail..the only way to really know is when you go to court and find out when the judge rambles off the charges….

In forums like these, a lot of people are not going to tell you the truth about what they were really doing before they failed the drug test or how much drugs they consumed, how often they consumed them and how fat they are…

So a general rule of thumb…the metabolites which break down weed in your body is what is being tested not thc itself. The metabolite which breaks down weed is called has a half-life of 5 days…so that means if you do have weed in your system and your body releases thc-cooh then it will die in 10 days…niacin helps with flushing fluids from your body..this is a scientific fact…

If you have thc-cooh in your urine and you take niacin then you will rid your body of the metabolite along with other things..this is a fact…how much weed you consumed will determine how often your body is producing thc-cooh to break down weed…

If you have been smoking every day for the last year and then you try to take niacin 7 days before to excrete thc-cooh then it’s highly likely you will fail.

You could take 2000mg a day of niacin and it’s not going to break down your fat any sooner if that was the case then all fat people would be on niacin..think about it it’s not rocket science…

So the bottom line niacin is not for people you heavily consume drugs frequently..Period!

It doesn’t work for those people..and if someone who consume a heavy amount of drugs frequently passes a drug test it was probably because he diluted his piss to such an extreme which allowed him to pass not the niacin…

I hope that helps…and I hope people stop trying to refute science..use niacin and other diuretics to help excrete elements from your body because scientist have already proved they are capable of doing so but stop slandering the usefulness of them because you never had a chance in hell to pass the drug test with or without niacin.


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