Vitamin B3 - Niacin

Information written and reviewed by Certified Doctors.

Niacin, also known as vitamin B3, helps:

  • release energy from the foods we eat
  • keep the nervous system and skin healthy

Good sources of niacin

There are two forms of niacin – nicotinic acid and nicotinamide – both of which are found in food.

Good sources of niacin include:

  • meat
  • fish
  • wheat flour
  • eggs
  • milk

How much niacin do I need?

The amount of niacin you need is about:

  • 16.5mg a day for men
  • 13.2mg a day for women

You should be able to get all the niacin you need from your daily diet.

Niacin can't be stored in the body, so you need it in your diet every day.

What happens if I take too much niacin?

Taking high doses of nicotinic acid supplements can cause skin flushes. Taking high doses for a long time could lead to liver damage.

There's not enough evidence to know what the effects might be of taking high daily doses of nicotinamide supplements.

What does the Department of Health advise?

You should be able to get the amount of niacin you need by eating a varied and balanced diet. If you take niacin supplements, don't take too much as this might be harmful.

Taking 17mg or less of nicotinic acid supplements a day or 500mg or less of nicotinamide supplements a day is unlikely to cause any harm.

Content supplied by NHS Choices