Niacin (Vitamin B3): Benefits, Risks And More

Even if you’re not familiar with niacin, there’s a good chance you’re regularly consuming it. Niacin, also known as vitamin B3, is one of the eight B-group vitamins and is found in a number of foods, from meat and poultry to nuts and legumes. It can also be taken as a dietary supplement.

As one of the essential vitamins the body needs, niacin plays a key role in various bodily functions, such as supporting the nervous and digestive systems and helping the body convert carbohydrates into energy.

Read on for everything you need to know about this key vitamin.

What Is Niacin?

Also known as vitamin B3, niacin is one of the eight B vitamins and is considered essential to a variety of metabolic processes. Niacin is a water-soluble vitamin, which means that any amount the body does not need is excreted in the urine rather than stored in the body.

Niacin is found in a variety of foods—sometimes it’s naturally occurring, while in other cases, it’s added to foods such as breads and cereals. Additionally, it’s possible to consume niacin in the form of a dietary supplement.

What Does Niacin Do?

Niacin is critical to a number of key bodily functions. In fact, according to Joel Evans, M.D., chief of medical affairs at the Institute for Functional Medicine and the founder and director of The Center For Functional Medicine, niacin is “actually the most important vitamin in the sense that it’s involved in more reactions in the body than other vitamin,” he says.

All of the body’s tissues convert niacin into its most active form, a coenzyme called nicotinamide adenine dinucleotide (NAD). In turn, NAD is used by over 400 enzymes to generate chemical reactions in the body. NAD is also converted into nicotinamide adenine dinucleotide phosphate (NADP), another coenzyme that enables reactions like the synthesis of cholesterol and fatty acids.

More specifically, “niacin is used to convert food into energy,” and is “important to the nervous system, skin and digestive system,” explains Amy Reed, a pediatric dietitian and spokesperson for the Academy of Nutrition and Dietetics.

Benefits of Niacin

Niacin offers a number of potential health benefits.

For one, niacin can help increase HDL cholesterol (or “good” cholesterol) and lower LDL cholesterol (“bad” cholesterol) and triglycerides. For this reason, doctors can prescribe high doses of niacin to help treat high cholesterol. However, studies have not found an association between niacin supplementation and reduced risk of cardiovascular disease or related death.[1]

Additionally, niacin is related to brain function. One study found that a higher intake of B vitamins, in particular niacin, throughout young adulthood was linked to improved cognitive function in midlife.[3]

Niacin also offers benefits to the skin, and as such, a type called niacinamide (also known as nicotinamide), is often included in skin care products. For instance, research suggests niacin may reduce the development of non-melanoma skin cancers in high-risk populations as well as prevent photoaging.[4]

It’s also possible that niacin may help with hypertension (or high blood pressure). A 2021 study of over 12,000 adults found an association between the consistent intake of niacin and the prevention of high blood pressure.[5]

How Much Niacin Do You Need?

The recommended daily intake of niacin varies depending on your age and sex, as well as whether you’re pregnant or breastfeeding. Males ages 19 and up generally need 16 milligrams of niacin equivalents (mg NE) per day, whereas females within that same age bracket should aim for 14 mg NE each day.

Those who are pregnant or breastfeeding should get slightly higher amounts of niacin per day. The recommended daily intake of niacin for pregnant individuals is 18 mg NE, while those who are lactating should aim for 17 mg NE.

Rather than not getting enough niacin, however, most people in the U.S. tend to consume more than the recommended daily amount of this B vitamin.[6]

Many common foods provide niacin. Among the top sources of niacin, or vitamin B3, are:

  • Red meat
  • Poultry
  • Fish
  • Nutritional yeast
  • Peanuts / peanut butter
  • Liver
  • Nuts and seeds
  • Fortified breads and cereals

Because niacin is found in so many different foods and because people generally don’t need a lot of it each day, niacin deficiency is not common. “Overall, a niacin deficiency is rare in a developed country like the U.S. due to the fact that it is well absorbed in most foods and is fortified in other foods,” says Reed.

Risks and Side Effects of Niacin

While it’s not common to get too much niacin through food, it’s possible when taking niacin as a supplement, particularly in high doses over the long term. According to Dr. Evans, this can lead to “annoying side effects” as well as “serious complications,” though per Dr. Evans, the latter “are truly rare.”

One potential side effect of excessive niacin is “niacin flush,” which is where “the head and neck and upper chest can get red,” explains Dr. Evans. This reddening may be accompanied by itchiness or a tingling on the face, arms and chest, as well as dizziness.

Other symptoms of niacin toxicity include:

  • Low blood pressure
  • Fatigue
  • Headache
  • Upset stomach and nausea
  • Blurred vision
  • Impaired glucose tolerance
  • Liver issues
  • Stomach ulcers

Additionally, niacin supplements can interact with some medications, including diabetes medications, blood thinners and blood pressure medications, according to Dr. Evans.

When to See a Doctor

According to Reed, “[i]t is always recommended to discuss the use of dietary supplements with your health care provider.”

In particular, those with conditions such as diabetes or high blood pressure or people who are taking other medications should speak with their doctor before beginning a niacin supplement, per Dr. Evans. Additionally, says Dr. Evans, if you’re taking any medications or have a chronic illness, then you may want to consult your doctor prior to taking a niacin supplement.

Further, as blood testing is usually not a reliable indication of niacin levels, a urine test is necessary to determine a deficiency. “If a person is concerned about their niacin status, it is recommended that they discuss a possible urine test to look for a possible niacin deficiency,” says Burns.



  1. Niacin. National Institutes of Health. Accessed 01/17/2024.
  2. Schandelmaier S, Briel M, Saccilotto R, et. al. Niacin for primary and secondary prevention of cardiovascular events. Cochrane Database Syst Rev. 2017 Jun 14;6(6):CD009744.
  3. Snaidr VA, Damian DL, Halliday GM. Nicotinamide for photoprotection and skin cancer chemoprevention: A review of efficacy and safety. Exp Dermatol. 2019;28 Suppl1:15-22.
  4. Zhang Z, Liu M, Zhou C, et al. Evaluation of Dietary Niacin and New-Onset Hypertension Among Chinese Adults. JAMA Netw Open. 2021;4(1):e2031669.
  5. Garg A, Sharma A, Krishnamoorthy P, Garg J, et. al. Role of Niacin in Current Clinical Practice: A Systematic Review. Am J Med. 2017 Feb;130(2):173-187.
  6. Qin B, Xun P, Jacobs DR Jr, et. al. Intake of niacin, folate, vitamin B-6, and vitamin B-12 through young adulthood and cognitive function in midlife: the Coronary Artery Risk Development in Young Adults (CARDIA) study. Am J Clin Nutr. 2017 Oct;106(4):1032-1040.


  1. Vitamin B. Better Health Channel. Accessed 01/17/2024.
  2. Niacin – Vitamin B3. Harvard T.H. Chan School of Public Health. Accessed 01/17/2024.
  3. Vitamin B3 (Niacin). Mount Sinai. Accessed 01/17/2024.

Important Notice: This article was originally published at  by Becca Stanek where all credits are due. Expert reviewed by Kara Collier, R.D.N., L.D.N.


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