niacin

noun

ni·​a·​cin ˈnī-ə-sən 

: an acid C₆H₅NO₂ of the vitamin B complex found widely in animals and plants and used especially against pellagra

also : nicotinamide

called also nicotinic acid

Examples of niacin in a Sentence

Recent Examples on the Web

Most varieties also contain B vitamins such as thiamin, niacin and folate. —Daryl Austin, USA Today, 3 May 2026

Spaghetti squash is a good source of vitamin C, vitamin B6, manganese, and niacin. —Carrie Madormo, Verywell Health, 1 May 2026

However, little research has explored the long-term effects of taking the vitamins on stroke risk, the optimal intake for preventing stroke, and whether other B vitamins—particularly thiamin, riboflavin, and niacin—might also have an effect. —Zoe Cunniffe, Health, 30 Apr. 2026

Six months after receiving niacin in addition to standard treatments (surgery, radiation and chemotherapy), 82% of the patients showed no disease progression, compared to the typical 54%, according to the study's press release. —Melissa Rudy, FOXNews.com, 31 Mar. 2026

Word History

Etymology

nicotinic acid + -in entry 1

First Known Use

1942, in the meaning defined above

Rhymes for niacin

• actomyosin
• tropomyosin
• myosin

Kids Definition

niacin

noun

ni·​a·​cin ˈnī-ə-sən 

: an acid of the vitamin B complex that is found widely in plants and animals and is used especially against pellagra

called also nicotinic acid

Medical Definition

niacin

noun

ni·​a·​cin ˈnī-ə-sən 

: a crystalline acid C₆H₅NO₂ that is a member of the vitamin B complex occurring usually in the form of a complex of niacinamide in various animal and plant parts (as blood, liver, yeast, bran, and legumes) and is used especially to lower LDL and triglyceride levels in the blood and to treat pellagra

called also nicotinic acid