What is Known as Vitamin B3 and Why is it Essential?

December 22, 2025 •

4 min read

According to the National Institutes of Health, severe vitamin B3 deficiency, a condition known as pellagra, was once a serious public health issue in parts of the U.S., but is now rare in developed countries due to fortified foods. This essential nutrient, however, remains vital for numerous bodily functions.

Quick Summary

Vitamin B3 is commonly known as niacin and exists in various forms, primarily nicotinic acid and nicotinamide. It is crucial for converting food into energy, supporting the nervous system, and maintaining healthy skin and digestion. A deficiency can lead to pellagra, while different forms offer distinct health benefits.

Key Points

Niacin is Vitamin B3: The generic term 'niacin' is most commonly known as vitamin B3, but it exists in multiple forms, including nicotinic acid and niacinamide.
Essential for Energy: All forms of niacin are crucial for synthesizing coenzymes (NAD+, NADP+) needed to convert food into cellular energy.
Different Forms, Different Effects: Nicotinic acid is primarily used therapeutically for high cholesterol but can cause flushing, while niacinamide is used in general supplements and skincare without this side effect.
Found in Many Foods: Vitamin B3 is readily available in both animal-based (meat, fish) and plant-based (nuts, fortified grains) foods.
Deficiency Causes Pellagra: A severe niacin deficiency can lead to pellagra, a serious condition affecting the skin, digestive system, and brain.
High-Dose Supplements Require Medical Supervision: High doses of niacin, particularly nicotinic acid, can cause side effects like flushing and potentially liver damage, and should be monitored by a doctor.

Understanding the Name: Niacin and Its Forms

What is known as vitamin B3? The answer is niacin, but this name actually encompasses several related compounds with distinct properties. The most common forms are nicotinic acid and nicotinamide, also known as niacinamide. While they both function to prevent niacin deficiency, their effects differ, particularly at higher supplemental doses. All forms are precursors to key coenzymes, nicotinamide adenine dinucleotide (NAD+) and its phosphate derivative (NADP+), which are central to cellular metabolism.

The Role of Niacin in Cellular Health and Beyond

Niacin is fundamental to the body's energy production. The coenzymes NAD+ and NADP+ are involved in over 400 biochemical reactions that help convert fats, carbohydrates, and proteins into usable energy. Without adequate niacin, cells cannot function correctly, and the systems with the highest energy demand, such as the skin, digestive tract, and brain, are often the first to show signs of deficiency. This vital function underscores why a balanced diet rich in niacin is essential for overall health.

Functions of Vitamin B3

Energy Metabolism: As a key component of the coenzymes NAD+ and NADP+, niacin facilitates the conversion of food into energy.
Nervous System Support: It is crucial for the proper function of the nervous system and can help protect brain cells from damage and stress.
Skin Health: Niacinamide, in particular, is used both orally and topically to protect skin cells from sun damage, reduce inflammation, and may even help prevent non-melanoma skin cancer.
Digestive System: It helps maintain the health of the digestive system, and a deficiency can lead to complications such as diarrhea and inflammation.
Cardiovascular Health: At high, therapeutic doses, nicotinic acid can be prescribed by a doctor to help manage cholesterol levels by increasing 'good' HDL cholesterol and lowering 'bad' LDL cholesterol.

Natural Sources of Vitamin B3

While many people get sufficient niacin from a balanced diet, it's important to know which foods are rich sources. Both animal and plant-based foods provide this vitamin. The body can also synthesize small amounts from the amino acid tryptophan, found in protein-rich foods.

Animal-Based Sources: Rich options include beef (especially liver), poultry (chicken and turkey breast), and fish like tuna and salmon.
Plant-Based Sources: Vegetarians and vegans can find niacin in fortified cereals and breads, brown rice, legumes, nuts (peanuts), seeds, and mushrooms.

Niacin vs. Niacinamide: A Comparison


Feature	Niacin (Nicotinic Acid)	Niacinamide (Nicotinamide)
Effect on Cholesterol	Used in high doses to increase HDL and lower LDL and triglycerides.	Does not have the same cholesterol-modifying effects.
Flushing	Known to cause uncomfortable skin flushing, tingling, and redness at therapeutic doses.	Does not typically cause flushing, making it better tolerated for supplementation.
Skincare Uses	Not typically used topically due to its flushing side effect.	A popular topical ingredient for improving skin texture, elasticity, and reducing redness.
Side Effects (High Doses)	Higher risk of side effects like flushing and, in rare cases, liver inflammation.	Safer at higher doses than nicotinic acid, with a lower risk of hepatotoxicity.
Primary Function	Prescription treatment for dyslipidemia, as well as nutritional support.	General nutritional supplement, often for cellular health, energy, and skin.

The Risks of Deficiency and Overdose

As mentioned, a severe niacin deficiency leads to pellagra, a condition characterized by the '4 Ds': dermatitis, diarrhea, dementia, and if left untreated, death. Symptoms of dermatitis include a symmetric, dark, and scaly rash on sun-exposed areas, sometimes forming a distinctive 'Casal's necklace' around the neck. Neurological symptoms like depression, memory loss, and confusion can also occur.

While deficiencies are uncommon, taking too much niacin from supplements can also be dangerous. The tolerable upper intake level for adults from fortified foods and supplements is 35 milligrams for nicotinic acid due to the risk of side effects like flushing. Very high doses of nicotinic acid (over 500 mg) can increase the risk of liver inflammation and other severe issues. Nicotinamide has a much higher upper limit, but liver toxicity is still possible at extremely high doses (above 3 grams/day). For this reason, supplemental niacin should only be taken under a doctor's supervision, especially at high doses.

The Verdict: Getting Your Vitamin B3

For the average person, consuming a varied and balanced diet that includes meat, fish, and fortified grains is sufficient to prevent niacin deficiency. If a deficiency is suspected or for therapeutic purposes such as managing cholesterol, a healthcare professional should be consulted. They can recommend the appropriate form and dosage, considering that the effects of niacin and niacinamide differ significantly at higher concentrations. Whether for cellular energy, neurological support, or maintaining skin integrity, understanding what is known as vitamin B3 and its forms is crucial for harnessing its benefits safely and effectively.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult with a healthcare professional before taking any vitamin B3 supplements.

Frequently Asked Questions

Niacin and niacinamide are both forms of vitamin B3. The primary difference is that niacin (nicotinic acid) can cause uncomfortable skin flushing and is sometimes used therapeutically to manage cholesterol, while niacinamide (nicotinamide) does not cause flushing and is often used in general supplements and skincare.

Pellagra is the disease caused by a severe deficiency of vitamin B3 (niacin). It is characterized by the "4 Ds": dermatitis (a rash on sun-exposed skin), diarrhea, dementia (neurological issues), and potentially death if left untreated.

Good food sources of niacin include animal products like poultry, beef, and fish, as well as plant-based options such as nuts, legumes, brown rice, and fortified cereals and breads.

Yes, it is possible to consume too much vitamin B3 from supplements. High doses, especially of nicotinic acid, can cause side effects like flushing and potentially liver damage. It is difficult to get a toxic amount from food alone.

In high, therapeutic doses prescribed by a doctor, niacin has been shown to increase 'good' HDL cholesterol and lower 'bad' LDL cholesterol and triglycerides. However, it is not a first-line treatment due to potential side effects.

While pregnant women have an increased daily requirement for niacin, high-dose supplemental niacin for conditions like high cholesterol is not recommended. Recommended daily intakes are usually met through a balanced diet, but supplementation should only be done under a doctor's guidance.

Yes, niacin is essential for proper brain function because it helps synthesize coenzymes needed for cellular energy. Deficiency has been linked to mental and neurological symptoms, and some research suggests it may help protect against cognitive decline.