6 Evidence-Based Vitamin B3 (Niacin) Benefits

Vitamin B3, also called niacin1, is a water-soluble vitamin found in many common foods such as chicken, tuna, beets, and lentils. It plays a role in countless bodily functions and helps convert the food we eat into energy.

Specifically, vitamin B3 plays an important role in digestion, mental health, heart health, the nervous system, maintaining healthy skin, making a variety of hormones, and acting as a precursor to the coenzyme nicotinamide adenine dinucleotide (NAD+).

But vitamin B3 is also a little more complex than your average vitamin. It's naturally found in several different forms—including nicotinic acid, nicotinamide, and nicotinamide riboside—each of which has a slightly different effect on the body.

Niacin is actually a blanket term for three different compounds2 that have similar activity in the body: nicotinic acid, nicotinamide (aka niacinamide), and nicotinamide riboside (NR). You'll find that "vitamin B3" and "niacin" are often used interchangeably to refer to these compounds.

Of these, nicotinic acid and nicotinamide are the main forms of vitamin B3 or niacin—they're both widely available from the same food sources and sold as dietary supplements. NR, on the other hand, is quite scarce in food and only recently started being sold as a supplement.

While all three forms of vitamin B3 share common traits, each has a slightly different effect on the body and serves a different role when taken as a supplement:

Nicotinic acid: This form of vitamin B3 is readily available from food. As a supplement, it's frequently used to manage high cholesterol and heart disease, and it often just goes by the name niacin. It also promotes circulation, and supplemental doses can cause what's called "niacin flush," skin that becomes red and itchy. Our bodies can convert nicotinic acid into nicotinamide.

[Pro tip: Many articles that reference "niacin" without specifying which form usually mean nicotinic acid—even though niacin is technically a blanket term. It's confusing, so we'll call everything by its true name in this article.]

Nicotinamide (aka niacinamide): This form of vitamin B3 is also readily available from food. It's the form that typically appears in multivitamins and fortified foods, like cereal, since it does not cause flushing. As a supplement, it doesn't treat cardiovascular conditions, but it does hold promise for treating skin3 conditions, arthritis4, and early-onset type 1 diabetes. Increasingly, it's also being added to skin care products (where it's often listed as niacinamide) for its anti-inflammatory and photoprotective perks.

Nicotinamide riboside (NR): Found predominantly in NR supplements (and in trace amounts in milk), NR is the most recently discovered form of vitamin B3. It's not commonly used, but it holds great promise in boosting cognitive function and slowing the aging process. Compared to the other two forms of vitamin B3, it is the most efficient5 at supporting neuronal NAD+ synthesis in the body and brain, which is really appealing.

Niacin is an essential nutrient, meaning you have to get it from the diet (or supplements in the amounts needed to see the health benefits. And since it's water soluble, your body doesn't store it, and you need regular, daily intake of it.

*Alcoholism is the main cause of vitamin B3 deficiency in the United States. Blood and urine tests can diagnose a deficiency.

Common symptoms of mild vitamin B3 deficiency, which can usually be addressed with diet changes and/or a multivitamin, often include indigestion, fatigue, canker sores and/or a bright red tongue, poor circulation, and depression.

High doses of vitamin B3 in the form of nicotinic acid are an established treatment for lowering "bad" LDL cholesterol, raising "good" HDL cholesterol, and lowering triglycerides, a type of fat found in your blood that can lead to atherosclerosis—a condition characterized by narrowing of the arteries due to fatty plaque buildup. Specifically, studies8 show that nicotinic acid favorably affects all lipids (e.g. raising HDL cholesterol and lowering LDL cholesterol and triglycerides), making it a natural alternative for treating patients with mixed hyperlipidemia. Additionally, nicotinic acid plays a role in altering the composition of LDL cholesterol particles from small and dense to large and more buoyant8. Larger LDL particles are far less damaging, suggesting that nicotinic acid could play a role in reducing risk of atherosclerosis.

But even though some research is promising, cardiologists like Joel Kahn, M.D., warn that this vitamin is not always a foolproof fix. "Generally we only need about 20 to 35 mg a day of niacin, but doses of up to 3,000 mg a day or more are used to control cholesterol," Dr. Kahn told mbg—and these high doses can be associated with issues like ulcers, muscle damage, and gout.

Failing to get adequate levels of vitamin B3 in your diet can lead to severe skin sensitivity and damage when exposed to sunlight. This makes sense when you understand that NAD+ plays a role in DNA repair9 and that low levels of vitamin B3 deplete NAD+.

In one animal study10, use of a topical cream containing nicotinamide decreased the risk of UV-induced skin cancers in mice. And in humans, a recent analysis11 of two prospective cohort studies following men and women for up to 26 years found that higher dietary intake of vitamin B3 (from food and oral supplements) may offer protection against certain types of skin cancer. This is good news since it suggests that you can consume enough vitamin B3 from food to reap this benefit. Sunscreens containing nicotinamide (where it's usually listed as niacinamide) are already on the market and may offer further protection.

Expanding on its skin-healing properties, both topical and oral nicotinamide may help treat acne as well—likely due to its anti-inflammatory properties. In a recent review13, researchers found that six out of eight studies using topical nicotinamide led to a significant reduction in acne or at least performed as well as more mainstream acne creams. And, two of the studies using an oral form of this vitamin led to a significant reduction in acne. Some researchers believe this form of vitamin B3 may be an effective way to treat severe acne without antibiotics. (Just remember, getting your diet and stress in check is super important for clear skin!)

Vitamin B3 has been shown to have anti-inflammatory effects14 in the body, which may translate to reduced joint pain and arthritis symptoms. In one small study15, patients with osteoarthritis who took a nicotinamide supplement were able to reduce the number of anti-inflammatory pain meds they used by 13 percent compared to the placebo group. They also experienced greater joint flexibility.

Vitamin B3 supports proper brain functioning, and a severe deficiency has been associated with dementia16, leading some researchers to believe that getting enough in your diet is crucial to the prevention of Alzheimer's disease. Deficiency has also been associated with symptoms of psychosis17, and supplemental nicotinic acid and nicotinamide has been used to treat schizophrenia18.

The form of vitamin B3 known as NR is of particular interest when it comes to brain health and Alzheimer's prevention, but research on this topic is still in it's infancy. In a recent study9, researchers found that the NR-treated mice had less DNA damage, higher neuroplasticity, increased production of new neurons, and lower levels of neuronal damage. In the hippocampus area of the brain (where damage and loss of volume is found in dementia), NR seemed to clear existing DNA damage or prevent it from spreading further. The mice also performed better on memory tests.

Vitamin B3 is critical for many digestive functions—the breakdown of carbs, fats, and alcohol—and keeping your GI tract happy. Low levels of vitamin B3 in the diet can cause an upset digestive system, and a severe deficiency can result in a disease called pellagra19, which causes diarrhea, vomiting, and other serious symptoms.

It's possible to get more than enough vitamin B3 from either plants or animals. But keep in mind, all B vitamins are water-soluble, which means you need to consume them every day since our bodies don't store them. Here are some of the best vitamin B3 foods.

Nutritional yeast* (¼ cup): 46 mg

Turkey (3 oz): 10 mg

Chicken (3 oz): 9 mg

Tuna (3 oz, canned): 8½ mg

Salmon (3 oz): 8½ mg

Bran flakes (¾ cup): 5 mg

Beef (3 oz): 4½ mg

Peanuts (1 oz): 4 mg

Mushrooms (1 sliced cup): 2½ mg

Lentils (1 cooked cup): 2 mg

Coffee (1 brewed cup): 2 mg

Whole-wheat bread (1 slice): 1½ mg

Beets (1 sliced cup): 1 mg

Most generally healthy people don't need to take a vitamin B3 supplement, since deficiency is rare and food sources are plentiful. Occasionally, though, doctors will prescribe a high dose of nicotinic acid or nicotinamide to treat a specific health condition, e.g., nicotinic acid for high cholesterol, especially if you can't tolerate statins. In these cases, following your doctor's dosing instructions carefully is crucial. 

If you're interested in using a vitamin B3 supplement to manage a minor health condition on your own, it's still wise to consult a health care provider about the appropriate dose and form. Many nicotinic acid and nicotinamide supplements contain doses that are far higher than the RDA (typically around 500 mg per dose), which could be dangerous or cause side effects if taken unnecessarily or incorrectly.

As supplements, these forms of vitamin B3 are usually well-tolerated at doses up to what would appear in a multivitamin or B-complex vitamin (usually around 50 milligrams), but at higher doses, they may carry more serious side effects, particularly nicotinic acid22.

They may also make seasonal allergies worse, as they trigger the release of histamine. With doses above 50 mg, nicotinic acid may also cause "niacin flush," or red flushed skin along with a burning or tingling sensation in the face or chest. Slow-release alternatives to nicotinic acid (under the name inositol hexaniacinate) may reduce flushing.

With very high doses of vitamin B3, like those used to treat specific health conditions, these supplements may cause liver damage, stomach ulcers, and nausea and vomiting, among other side effects. That's why doctors recommend periodic blood tests to check liver function with doses above 100 mg per day. High doses may also increase blood sugar, so people with diabetes should be cautious.

Unlike the more common forms of vitamin B3, nicotinic acid and nicotinamide, you can only get NR in meaningful quantities from supplements.* While more research is needed, preliminary research shows that these supplements support normal levels of the coenzyme NAD+, which promotes cellular metabolism and energy production.*