Does Niacin Cleanse out Drugs?

If you use marijuana, cocaine or other illegal drugs and want to alter test results demanded by a potential employer, don’t expect niacin to help 4. No clinical evidence suggests that niacin can cleanse drugs from your system. You might harm your health if you take large doses of niacin in an effort to pass a drug-screening test 4.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Poisoning Effects

Lack of evidence doesn’t stop people from trying niacin as a means to fool drug urine tests 4. Poison control centers in the United States logged more than 3,100 reports in 2005 from persons using niacin for non-medical reasons, including efforts to pass drug tests 4. Some callers, who complained of symptoms such as:

  • rashes
  • vomiting
  • reddened skin
  • tachycardia – rapid heartbeat – said they had taken as much as 8,000 mg of niacin

Your normal diet includes about 14 to 16 mg of niacin a day.

Niacin and Metabolism

Some logic, if not science, supports the notion that niacin could clean drugs out of your system. Niacin in your diet, obtained from foods such as:

  • nuts
  • fish
  • beef
  • chicken
  • fortified breakfast cereals
  • promotes healthy digestion

Your body needs niacin to convert carbohydrates into fuel and to metabolize protein and fat. If a small amount of niacin helps metabolize a full day’s supply of food, you might think that a large supply could rid your body of accumulated drug chemicals 4. Although some drug users report success using niacin as a detoxifying agent, their anecdotes are not the result of clinical tests 4.

How to Pass Drug Screening Test

If you want to pass a drug-screening test, quit using drugs. In general, it takes three to 30 days for THC, the active ingredient in marijuana, to leave your system. Persons with a fast metabolism might pass a test a week after they’ve used marijuana – with or without taking niacin 4. For some, THC might show up in tests past the 30-day mark. Other drugs may take up to 30 days to leave your system.


Taking niacin in large doses – more than 100 mg – poses serious health risks. Persons taking niacin may develop stomach ulcers, gout or liver damage. Niacin can worsen kidney disease and cause dramatic blood sugar elevations in people with type 2 diabetes. Other side effects include irregular heartbeat and loss of vision. The National Institutes of Health ended a niacin study in May 2011, which was 18 months earlier than planned, after persons who took 2,000 mg of niacin suffered more than twice as many strokes as study participants who did not take niacin.