What's the difference between vitamin B3 and niacin? Understanding the Forms of this Essential Nutrient

October 28, 2025 •

4 min read

While most people are aware of the importance of B vitamins, a common point of confusion exists regarding the precise relationship between vitamin B3 and niacin. The simple answer to what's the difference between vitamin B3 and niacin? is that vitamin B3 is the umbrella term for several related compounds, and niacin (nicotinic acid) is one of its primary forms.

Quick Summary

Vitamin B3 is a group of compounds, with niacin (nicotinic acid) and niacinamide being the most common forms. While they share functions related to metabolism, their effects, especially concerning side effects like flushing and medical applications, are distinct.

Key Points

Vitamin B3 vs. Niacin: Vitamin B3 is the broader term for the nutrient, while niacin is one specific form of it, also known as nicotinic acid.
Two Primary Forms: The two main active forms of vitamin B3 are niacin (nicotinic acid) and niacinamide (nicotinamide).
The Flushing Effect: High doses of niacin cause an uncomfortable, but harmless, skin flushing effect due to vasodilation, which niacinamide does not cause.
Different Medical Uses: High-dose niacin is used for cholesterol management, while niacinamide is the preferred treatment for pellagra (vitamin B3 deficiency).
Skincare Applications: Niacinamide is a popular topical ingredient for improving skin texture, reducing redness, and controlling oil production.
Dietary Sources: Both forms are found naturally in foods like meat, fish, nuts, and fortified grains, and the body can convert the amino acid tryptophan into niacinamide.
Supplementation Caution: High-dose supplementation with either form, especially niacin, requires medical supervision due to potential adverse effects like liver damage.

Demystifying the Niacin and Vitamin B3 Relationship

Vitamin B3 is a water-soluble vitamin essential for hundreds of bodily functions, including converting food into energy, supporting the nervous system, and maintaining skin health. The term 'niacin' is often used interchangeably with vitamin B3, but this can be misleading because niacin is just one of several compounds that make up this vitamin family. Specifically, vitamin B3 exists in two primary forms: niacin (or nicotinic acid) and niacinamide (also called nicotinamide). Each of these forms, while metabolically related, has a unique impact on the body, especially when taken as a supplement in high doses.

The Role of Nicotinic Acid (Niacin)

Nicotinic acid, commonly referred to as niacin, is the form historically used in high doses as a therapeutic treatment for dyslipidemia, a condition characterized by abnormal levels of cholesterol and triglycerides. When prescribed by a doctor, large doses of nicotinic acid can help lower 'bad' LDL cholesterol and raise 'good' HDL cholesterol. However, this form is well-known for an unpleasant side effect known as 'niacin flush'.

The Niacin Flush The flush is a harmless but uncomfortable reaction that can cause the face, neck, and upper body to turn red, warm, and itchy. This occurs because high doses of niacin cause small blood vessels near the skin's surface to dilate, increasing blood flow. While many people develop a tolerance to it over time, the flush is a primary reason for discontinuation of niacin therapy. For this reason, extended-release and slow-release formulations were developed to mitigate this effect, although they also carry a higher risk of liver toxicity. Due to advancements in statin therapies and the adverse side effects of high-dose niacin, its use for cholesterol management has become less common.

The Role of Niacinamide (Nicotinamide)

Niacinamide, or nicotinamide, is the other major form of vitamin B3. Unlike nicotinic acid, niacinamide does not cause the flushing side effect, making it the preferred form for supplementation in treating severe deficiency, known as pellagra. The body can convert excess niacin into niacinamide. In addition to its role in preventing deficiency, niacinamide has gained significant popularity for its benefits in skincare.

Skincare Benefits When applied topically in serums and creams, niacinamide has anti-inflammatory properties that can help soothe redness and improve skin texture. It is also known to help reduce the appearance of dark spots, regulate oil production, and support the skin's natural moisture barrier. This makes it a versatile ingredient suitable for most skin types, including sensitive and acne-prone skin.

Functions of Vitamin B3 (Niacin and Niacinamide)

Despite their differences in effects at high supplemental doses, both niacin and niacinamide are converted by the body into the essential coenzymes nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+).

Energy Metabolism: NAD+ and NADP+ are crucial for converting proteins, fats, and carbohydrates from food into usable energy (ATP).
Cellular Processes: These coenzymes play a vital role in cellular signaling, DNA repair, and gene expression.
Antioxidant Function: They help neutralize free radicals, protecting the body from oxidative damage.

Excellent Food Sources of Vitamin B3

Maintaining a healthy diet rich in vitamin B3 is the best way to prevent deficiency. A variety of foods, both animal and plant-based, are excellent sources of this nutrient.

Animal-Based Sources:

Liver
Chicken breast
Tuna
Turkey
Salmon
Pork

Plant-Based Sources:

Peanuts
Brown rice
Mushrooms
Potatoes
Avocado
Legumes (such as green peas)

Many refined grains and cereals are also fortified with highly bioavailable niacinamide.

Niacin vs. Niacinamide: A Comparison Table


Feature	Niacin (Nicotinic Acid)	Niacinamide (Nicotinamide)
Causes Flushing?	Yes, especially in high supplemental doses.	No, it does not cause flushing.
Cholesterol Benefits?	Can improve cholesterol levels at high, therapeutic doses, but is often associated with side effects.	Does not significantly affect cholesterol levels.
Common Use (Supplement)	Historical treatment for high cholesterol, but less common today due to side effects and newer medications.	Used to prevent and treat vitamin B3 deficiency (pellagra).
Common Use (Topical)	Not typically used topically.	Widely used in skincare products for anti-inflammatory and skin-barrier benefits.
Safety Concerns	High doses (1,000+ mg) can cause liver damage and other side effects; requires medical supervision.	Generally fewer side effects than niacin; very high doses can still have adverse effects.
Bioavailability in Food	Found mainly in animal-based foods; niacin in some plant-based foods is less bioavailable.	Common in animal-based foods and fortified grains; body converts tryptophan to niacinamide.

Conclusion: Choosing the Right Form of Vitamin B3

To conclude, while the terms 'niacin' and 'vitamin B3' are often used interchangeably, it is more accurate to understand vitamin B3 as the family of compounds that includes niacin (nicotinic acid) and niacinamide (nicotinamide). The key functional difference lies in their effects, particularly at high supplemental doses. Niacin, in its nicotinic acid form, can cause the uncomfortable flushing effect and, at therapeutic doses, has effects on cholesterol and requires careful medical supervision due to risks like liver damage. Niacinamide does not cause flushing and is safer for supplementation to address a deficiency, as well as being a popular ingredient in topical skincare products. The average person gets enough vitamin B3 from a balanced diet, but for high-dose supplementation, knowing the difference is crucial. As with any supplement, consulting a healthcare professional is always recommended before starting a high-dose vitamin B3 regimen.

For more detailed information on supplement safety, you can visit the Office of Dietary Supplements at the National Institutes of Health.

Frequently Asked Questions

No, niacin is a specific form of vitamin B3, also known as nicotinic acid. Vitamin B3 is the general term for a group of compounds, which includes both niacin and niacinamide.

Only the niacin (nicotinic acid) form has a notable effect on cholesterol at high, therapeutic doses. However, due to side effects and the availability of newer medications, it is less commonly used and should only be taken under medical supervision.

Niacin flush is a temporary side effect of taking high supplemental doses of niacin (nicotinic acid). It causes a reddening, warmth, or itching sensation on the skin due to the dilation of blood vessels.

No, niacinamide (nicotinamide) does not cause the flushing effect associated with niacin. This is why it is the preferred form for treating severe vitamin B3 deficiency, as it can be taken in higher doses without this side effect.

Most supplements will specify the form on the label. Look for the ingredient listed as 'niacin' (nicotinic acid) or 'niacinamide' (nicotinamide). If it only says 'niacin', it's most likely nicotinic acid.

Excellent food sources include meat (liver, chicken, pork), fish (tuna, salmon), nuts (peanuts), seeds, legumes, mushrooms, and fortified grain products.

Yes, niacinamide is a popular topical ingredient in skincare products for its anti-inflammatory and skin-barrier strengthening benefits. It helps improve skin texture, reduce redness, and regulate oil production.

While natural sources in food are not a concern, taking high doses of supplemental vitamin B3, especially niacin, can lead to side effects. Excess niacin can cause liver damage, and both forms can cause issues in very high amounts. Always consult a healthcare professional before taking high-dose supplements.