Niacin, also called vitamin B3, is part of the family of B-complex vitamins. Niacin is an essential nutrient that is utilized in so many body processes they can’t all be listed here. As a coenzyme – a molecule that enables chemical processes in the body to occur – niacin is involved in more than 400 reactions. Some of the most important functions transform the food you eat into energy for your cells. Other functions include tissue repair, making new cells, regulating cholesterol and blood fats, regulating metabolic processes, and maintaining brain health and skin health. Many of the most significant enzymatic reactions are related to NAD+ and NADP, which you can read more about here.

As you learn more about niacin, you will quickly see there are multiple names for it. Some of these names mean the same thing, while others are names for specific forms of niacin – in foods, supplements, or the body – that have slightly different functions. The following guide will help you understand what each form of niacin does.

1. Niacin

The basic term niacin refers to vitamin B3. Synonymous names include niacinamide, nicotinamide, nicotinic acid, nicotinic acid amide, crystalline niacin, and B3, and these names are considered to be interchangeable in a general discussion of niacin, although the names are not truly synonymous.

• Amides: niacinamide, nicotinamide, nicotinic acid amide, and NAM are the EXACT same thing. They are the basic “amide” form of vitamin B3 – the most common form found in food and nutritional supplements. The amide form is very adequate for the prevention of serious niacin deficiency, which is known as pellagra. Your body also makes nicotinamide as a breakdown product of nicotinamide adenine dinucleotide (NAD+) after NAD+ does its job in your cells.
• Acids: Nicotinic acid and niacin are names for the same thing – the standard acidic form of crystalline niacin. You can also find this form in foods and nutritional supplements, although it is less common. For the most part, the amide and acid forms of niacin do the same thing, but with two differences: first, the acid form contributes to the production and balance of cholesterol and blood fats, and second, this form causes the well-known “niacin flush” – a harmless and temporary vascular reaction to this form of niacin that occurs in some individuals, particularly when they take a high dose.

2. Inositol hexaniacinate

It’s also called inositol nicotinate, “no-flush,” or “flush-free” niacin. It is six molecules of niacin bound to another vitamin-like compound called inositol. As its nickname implies, it was developed as a version of the acid form of niacin that would reduce or eliminate flushing – providing niacin’s cardiovascular health benefits without its uncomfortable side effects.1

3. Nicotinamide riboside (NR)

NR is a special form of niacin that is found in small quantities in food and some nutritional supplements. Although less common in nature than other forms of niacin, NR is the most active precursor to NAD+, which has made NR the focus of a large amount of research. Although we know that all forms of niacin play some role in health by contributing to NAD+ production, NR appears to be uniquely potent in this regard, and thus offers more benefits for healthy aging, metabolic health, energy production, and more.*

4. Nicotinamide mononucleotide (NMN)

NMN is made in the body from NR and can also be found as an ingredient in some nutritional supplements. NMN is also found in very small quantities in foods like edamame, beef, and avocado. From a health standpoint, studies are looking at whether NMN and NR have similar properties.2

5. Methylnicotinamide (MeNAM)

You won’t find this form of niacin in food or supplements – only in the body where it is made in the liver from the metabolism of nicotinic acid or the breakdown of NAD+. Because excess MeNAM buildup can be harmful, the body naturally eliminates it via the kidneys. However, individuals with genetic mutations, such as the MTHFR gene mutation, can have a poor ability to eliminate MeNAM unless they have adequate levels of the nutrients that support this process.

6. 1‐Methylnicotinamide chloride (1‐MNA)

This form of niacin, which is derived from MeNAM, is found naturally in small quantities in green tea and some fungi.3 Although not available in the United States, 1-MNA is found in cosmetics and nutritional supplements in Europe. While it is currently used primarily as a topical to assist with skin irritation and skin aging, it is also being studied to support immune health.4

7. Tryptophan

Well, okay, tryptophan is not a form of niacin, it’s an amino acid, but it’s important to this conversation because your body can use tryptophan to make NAD+. NAD+ is simply so important in the body that you have three different ways to make it: one from all the acid forms of niacin, one from all the amide forms, and one from tryptophan. Less than two percent of the tryptophan you consume is converted to NAD+, and it takes about 60 grams of tryptophan to equal the potency of one mg of niacin.5 Because adults need 14-16 mg of niacin or niacin equivalents daily, it would be inefficient to get it all from tryptophan, although in theory it could be done.

While niacin in its most basic form is an essential nutrient that you need to prevent deficiency, there can be many other health benefits depending on the form you choose.

References

1. Kazmi D, Abidi A, Azhar A, et al. Abstract 14436: Inositol hexanicotinate is a safe and effective alternative of niacin. . . . Circulation 2019;140(Suppl 1):A14436-A14436.
2. Hong W, Mo F, Zhang Z, et al. Nicotinamide mononucleotide: a promising molecule for therapy of diverse diseases by targeting NAD+ metabolism. Front Cell Dev Biol 2020;8.
3. Turck D, Bresson J, Burlingame B, et al. Safety of 1-methylnicotinamide chloride (1-MNA) as a novel food pursuant to Regulation (EC) No 258/97. EFSA J 2017;15(10):e05001.
4. Kilgour M, MacPherson S, Zacharias L, et al. 1-Methylnicotinamide is an immune regulatory metabolite. . . . Sci Adv 2021;7(4):eabe1174.
5. Goldsmith G. Niacin-tryptophan relationships in man and niacin requirement. Am J Clin Nutr 1958;6(5):479-486.

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