Vitamin B3 (Niacin & Niacinamide)

Niacin, also known as vitamin B3, is an essential nutrient that supports energy production, DNA repair, and nervous system function. A blood niacin test measures whether you have adequate levels of this vitamin. Deficiency can cause fatigue, skin problems, and neurological issues, while severe deficiency leads to pellagra. Most people get sufficient niacin from diet, but supplementation may be needed in certain conditions or dietary restrictions.

Nicotinamide, also known as niacinamide, is a form of vitamin B3 (niacin) essential for energy production, DNA repair, and cell signaling. Unlike nicotinic acid (the other form of B3), nicotinamide does not cause flushing. Your body obtains nicotinamide from foods like chicken, tuna, and mushrooms, or synthesizes it from tryptophan. Low levels are rare in developed countries but can occur with severe malnutrition, certain medications, or genetic disorders affecting niacin metabolism. This test helps assess nutritional status and may be useful in evaluating fatigue or neurological symptoms.