Nicotinic acid

Studies in people

• Benefit

  Fatty liver disease²

  People who ate more niacin in food were less likely to have fatty liver disease.

• Benefit

  Eye health in diabetes³

  People who ate more niacin in food were less likely to have diabetic eye disease, though this link is not proof.

• Benefit

  Suicidal thoughts⁴

  People who ate more niacin were less likely to report suicidal thoughts, though this link is not proof of cause.

• Concern

  Side effects of vitamin B3⁵

  Niacin and nicotinamide can cause stomach upset, liver problems, flushing, rash and tiredness, and these are more common at higher doses.

• Open question

  Migraine risk⁶

  People who ate more niacin had fewer migraines, but scientists do not yet know whether niacin prevents them.

• Benefit

  Eye health and glaucoma⁸

  In US adults aged 40 and over, eating more niacin was linked to a lower chance of glaucoma.

• Open question

  Skin cancer risk⁹

  In people, eating more niacin was linked to slightly fewer squamous cell skin cancers but slightly more basal cell cancers.

• Benefit

  Blood fat levels¹⁰

  People who ate more nicotinic acid in food had lower risk of unhealthy blood fat levels.

• Open question

  Blood pressure risk¹¹

  In Chinese adults, dietary niacin intake showed a J-shaped link with new-onset hypertension, lowest risk at 14.3 to 16.7 mg/d.

• Concern

  Prostate health in older men¹²

  Older men who ate more niacin were more likely to report an enlarged prostate, though the study cannot prove cause.

• Open question

  Eye pressure and glaucoma¹³

  People with glaucoma, especially with normal eye pressure, tended to eat less niacin.

Animal and lab studies only

• Open question

  Aging and cell health¹⁵

  Nicotinic acid is a form of vitamin B3 that yeast studies suggest may affect how cells age.

• Benefit

  Zinc and iron absorption¹⁶

  In animal studies, nicotinic acid helped mice absorb more zinc and iron from their food.

Study type not stated

• Benefit

  How cells make energy¹⁴

  Nicotinic acid helps the body make NAD, which cells need for metabolism and respiration.

How it’s made and used

• Gum disease risk⁷

  In Korean adults, eating too little nicotinic acid was linked to periodontitis, but not gingivitis.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.