Niacinamide, also known as nicotinamide, vitamin B3 or vitamin PP, is a water-soluble vitamin that belongs to the B vitamins. Niacinamide is a white needle-like crystal or crystalline powder, odorless or slightly foul, with a slightly bitter taste. The relative density is 1.4, and the melting point is 129-131°C. 1g of this product can be dissolved in 1mL of water, 1.5mL of ethanol or 10mL of glycerin, Chemicalbook is insoluble in ether. The pH of 10% aqueous solution is 6.5-7.5. Has weak hygroscopicity. It is relatively stable, resistant to acid, alkaline and high temperature, stable to light and heat in dry air, and generates nicotinic acid when heated in alkaline or acidic solution. In nature, it mainly exists in cereal husks, yeast, peanuts, meat, animal organ offal, milk and green leafy vegetables. It can be synthesized by tryptophan in the human body, but the efficiency is extremely low. Escherichia coli in the intestinal tr act can synthesize niacin and then convert it into niacinamide.