Vitamin B3 (Niacin, niacinamide)

Niacin is a water-soluble vitamin and is part of the vitamin B group. Niacin, also known as vitamin B3 and nicotinic acid plays an essential role in various enzyme driven reactions within the synthesis of fatty and amino acids and in the metabolism of carbohydrates as well.


Healthy adult horses are able to synthesize b-complex vitamins in sufficient quantities via the bacteria in the large intestine (colon) if they are given enough forage. Particularly rich in niacin are legumes (alfalfa, clover).


No studies have been conducted to establish the requirements of the horse for niacin as healthy adult horses normally are able to cover their daily needs by microbiological activity of their hind gut bacteria when fed a balanced diet.


Moldy hay, rations low in crude fiber, sudden feed changes or oral application of medications with a bacteriostatic effect can in principle result in a deficiency of B-complex vitamins, as the horse is virtually unable to store them.

A niacin deficiency is conceivable after excessive and one-sided intake of grain corn combined with lower intake of tryptophan. However, the effects of a niacin deficiency have not yet been investigated in horses.

If low synthesis of the intestinal flora is to be feared with rations rich in concentrated feed and low in crude fiber (e.g., in high-performance horses), a supplementation of b-complex vitamins should be considered.


Due to the fact that healthy adult horses are able to synthesize the required amounts of several b-complex vitamins, an excecss is very unlikely and only may occur with a very low likelyhood after heavy abuse of b-complex vitamin enriched supplements.

Important to know

Horses suffering from intestinal inflammation, malabsorption, diarrhea or overall loss of appetite can have a benefit when being supplemented with b-complex vitamins due to the lack of microbioal activity. Weak foals can be suported with b-complex vitamins to stimulate their appetite and provide them with essential vitamins as well.