Understanding Niacin Deficiency

Niacin is an essential nutrient that most people get through diet. Also known as vitamin B3, it helps keep your skin and nervous system healthy. It also helps turn food into energy.

A niacin deficiency is a serious, life-threatening condition that is most common in countries where food is scarce. It can also happen if you have certain health conditions or trouble accessing nutritious foods.

This article discusses signs of niacin deficiency and how to increase niacin in your diet.

Raw salmon fillet

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Niacin Deficiency Symptoms

Symptoms of a slight niacin deficiency can be so mild that you don't notice them at first. But if this deficiency continues, it can lead to a condition called pellagra. Pellagra has some key characteristics known as "the four Ds," which generally appear in this order:

Signs and symptoms of pellagra can include:

Without treatment, pellagra can lead to death within a few years.


Niacin is an essential nutrient. In the United States, many common foods are enriched with B vitamins, so niacin deficiency is rare.

How much niacin you need every day depends on your age and sex.

Risk Factors for Niacin Deficiency

It can be challenging to get enough niacin if you don't have regular access to nutritious foods. The condition that results is called primary pellagra. Secondary pellagra is when you're malnourished due to conditions such as:

After about six months, the body can make some niacin from an amino acid called tryptophan. Turkey is probably the best-known source of tryptophan. To convert from tryptophan to niacin, you need to get adequate amounts of iron, riboflavin (B2), and pyridoxine (B6). A lack of these nutrients can also lead to niacin deficiency.

How to Test for Niacin Deficiency

A healthcare provider may be able to make the diagnosis based on your symptoms. You can confirm this by taking a simple blood test.

Your healthcare provider might also order a urine test. This may involve a random urine sample or a 24-hour urine test. A laboratory analysis can determine if you're deficient in niacin and other B vitamins.

How to Get More Niacin

Many foods contain niacin naturally. You can also find it in fortified foods like bread and cereals. Some good sources of niacin are:

  • Meats and meat products, particularly beef liver
  • Poultry, such as turkey and chicken
  • Marinara sauce
  • Fish, such as salmon and tuna
  • Nuts and legumes
  • Whole grains, enriched bread, rice, cereals

You can take a dietary supplement if you don't get enough niacin through diet. You can get niacin in multivitamins, B-complex vitamins, and B3 vitamins. A healthcare provider can make a recommendation based on your test results and overall health.

Can You Have Too Much Niacin?

Taking too much niacin should be avoided. Unless your healthcare provider prescribes a higher amount, don't take more than the upper limit, which is 35 milligrams per day for adults.

Higher doses can cause a reaction called "niacin flush." Symptoms of niacin flush include redness of the skin (face, arms, and chest), tingling, burning, and itching. Symptoms usually go away within a half hour. While it's not dangerous, it can be somewhat uncomfortable.

In some cases, flushing is accompanied by other symptoms such as:

  • Headache
  • Rash
  • Dizziness
  • Blood pressure changes

Serious adverse effects can occur if you take over 1,000 milligrams a day over a long period. Dietary supplements can interact with other medications. Talk to your healthcare provider before adding niacin supplements to your daily routine.


Niacin, or vitamin B3, is essential to life. It provides you with energy and keeps your skin and nervous system functioning. Niacin deficiency, known as pellagra, is serious and life-threatening. Symptoms may be mild initially but can escalate to severe digestive, skin, and nervous system problems. Many foods are fortified with niacin. You can also get niacin by taking dietary supplements. Work closely with your healthcare providers or a dietitian to ensure you get the necessary nutrients.

A Word From Verywell

Over time, symptoms of niacin deficiency get more severe and dangerous. Eating foods rich in niacin can help prevent this from happening. If you already have symptoms of niacin deficiency, see a healthcare provider as soon as possible. A simple blood or urine test can determine if that's the case. Some dietary changes or supplements can improve symptoms and help you quickly feel better.

Frequently Asked Questions

  • Is niacin the same as B3?

    Niacin is a form of vitamin B3. It's also known as nicotinic acid.

  • Can niacin damage your liver?

    It's not common, but yes, it can happen when you take high doses of extended-release nicotinic acid over a long period.

  • How long does it take for niacin to take effect?

    Niacin doesn't build up in your system, so you need to take in niacin daily. Symptoms of niacin deficiency, such as dementia, can change within hours of beginning niacin therapy. Other neurological and skin problems may improve within two days.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institutes of Health. Office of Dietary Supplements. Niacin fact sheet for consumers.

  2. American Osteopathic College of Dermatology (AOCD). Pellagra.

  3. National Institutes of Health. Niacin. Fact sheet for professionals.

  4. Mielgo-Ayuso J, Aparicio-Ugarriza R, Olza J, et al. Dietary intake and food sources of niacin, riboflavin, thiamin and vitamin b6 in a representative sample of the Spanish population. The anibes study. Nutrients. 2018;10(7):846. doi:10.3390/nu10070846

  5. Meyer-Ficca M, Kirkland JB. Niacin. Advances in Nutrition. 2016;7(3):556-558. doi:10.3945/an.115.011239

Additional Reading

By Ann Pietrangelo
Ann Pietrangelo is a freelance writer, health reporter, and author of two books about her personal health experiences.