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Niacin And Niacinamide (Vitamin B3)

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What other names is Niacin known by?

3-Pyridinecarboxylic Acid, Acide Nicotinique, Acide Pyridine-Carboxylique-3, Anti-Blacktongue Factor, Antipellagra Factor, B Complex Vitamin, Complexe de Vitamines B, Facteur Anti-Pellagre, Niacina, Niacine, Nicosedine, Nicotinic Acid, Pellagra Preventing Factor, Vitamin B3, Vitamin PP, Vitamina B3, Vitamine B3, Vitamine PP.

What is Niacin?

Niacin is a form of vitamin B3. It is found in foods such as yeast, meat, fish, milk, eggs, green vegetables, and cereal grains. Niacin is also produced in the body from tryptophan, which is found in protein-containing food. When taken as a supplement, niacin is often found in combination with other B vitamins.

Do not confuse niacin with niacinamide, inositol nicotinate, IP-6, or tryptophan. See the separate listings for these topics.

Niacin is taken by mouth for high cholesterol and other fats. It is also used for low levels of a specific type of cholesterol, HDL. It is also used along with other treatments for circulation problems, migraine headache, Meniere's syndrome and other causes of dizziness, and to reduce the diarrhea associated with cholera. Niacin is also taken by mouth to for preventing positive urine drug screens in people who take illegal drugs.

Niacin is taken by mouth for preventing vitamin B3 deficiency and related conditions such as pellagra. It is also taken by mouth for schizophrenia, hallucinations due to drugs, Alzheimer's disease and age-related loss of thinking skills, chronic brain syndrome, muscle spasms, depression, motion sickness, alcohol dependence, blood vessel swelling linked with skin lesions, and fluid collection (edema).

Some people take niacin by mouth for acne, leprosy, attention deficit-hyperactivity disorder (ADHD), preventing premenstrual headache, improving digestion, protecting against toxins and pollutants, reducing the effects of aging, arthritis, lowering blood pressure, improving circulation, promoting relaxation, improving orgasms, and preventing cataracts. It is also used to improve exercise performance.

Likely Effective for...

  • Abnormal levels of blood fats. Some niacin products are FDA-approved prescription products for treating abnormal levels of blood fats. These prescription niacin products typically come in high strengths of 500 mg or higher. Dietary supplement forms of niacin usually come in strengths of 250 mg or less. Since very high doses of niacin are required for improving cholesterol levels, dietary supplement niacin usually isn't appropriate. For most people who need to lower low-density lipoprotein (LDL or "bad") cholesterol, niacin is considered a second-line therapy. But it may be used as a first line of treatment in people with high levels of both cholesterol AND blood fats called triglycerides. Niacin may be combined with other cholesterol-lowering drugs when diet and single-drug therapy is not enough.
  • Treatment and prevention of niacin deficiency, and certain conditions related to niacin deficiency such as pellagra. Niacin is approved by the U.S. Food and Drug Administration (FDA) for these uses. However, using niacinamide instead of niacin is sometimes preferred because niacinamide doesn't cause "flushing," (redness, itching and tingling), a side effect of niacin treatment.

Possibly Effective for...

  • Hardening of the arteries (atherosclerosis). Taking niacin by mouth along with medicines called bile acid sequestrants seems to reduce hardening of the arteries in men with this condition. It seems to work best in people with high levels of blood fats called triglycerides prior to treatment. Taking niacin with cholesterol-lowering medications also seems to reduce the risk of adverse heart-related adverse events in people with a history of narrowing or hardening of the arteries.
  • Diarrhea from an infection called cholera. Taking niacin by mouth seems to control the loss of fluid due to cholera.
  • Abnormal levels of blood fats in people with HIV/AIDS. Taking niacin seems to improve levels of cholesterol and blood fats called triglycerides in HIV/AIDS patients with abnormal blood fat levels due to antiretroviral treatment.
  • Metabolic syndrome. Taking niacin seems to increase levels of high-density lipoprotein (HDL or "good") cholesterol and reduce levels of blood fats called triglycerides in people with metabolic syndrome. Taking the niacin along with a prescription omega-3 fatty acid seems to work even better.

Insufficient Evidence to Rate Effectiveness for...

  • Alzheimer's disease. People who consume higher amounts of niacin from food and multivitamins seem to have a lower risk of getting Alzheimer's disease than people who consume less niacin. But there is no evidence that taking a stand-alone niacin supplement helps to prevent Alzheimer's disease.
  • Cataracts. Taking niacin by mouth might reduce the risk of nuclear cataracts. Nuclear cataract is the most common type of cataract.
  • Erectile dysfunction. Taking extended-release niacin seems to help men with erectile dysfunction maintain an erection during sexual intercourse.
  • Exercise performance. Research shows that taking a supplement containing niacin and other ingredients before exercise does not improve performance during exercise in men.
  • High levels of phosphate in the blood (hyperphosphatemia). High blood levels of phosphate can result from kidney dysfunction. Some early research shows that taking niacin by mouth can reduce blood levels of phosphate in people with end-stage kidney disease and high levels of blood phosphate. But other research shows that taking niacin by mouth at a higher dose does not lower blood phosphate levels when taken along with medication used to lower blood phosphate levels.
  • Acne.
  • Alcohol dependence.
  • Attention deficit-hyperactivity disorder (ADHD).
  • Depression.
  • Dizziness.
  • Drug-induced hallucinations.
  • Migraine or premenstrual headache.
  • Motion sickness.
  • Schizophrenia.
  • Other conditions.
More evidence is needed to rate niacin for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).


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