Vitamin B3 Test

Vitamin B3, also known as niacin, is a water-soluble nutrient that your body relies on to convert food into energy and to support healthy skin, brain function, and digestion. It exists in two key forms—nicotinic acid and nicotinamide—which are converted into the active coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate). These coenzymes are essential players in hundreds of cellular reactions that manage energy use, repair DNA, regulate stress responses, and maintain optimal cell function.

Although the body can synthesize vitamin B3 from the amino acid tryptophan, this pathway is inefficient and dependent on sufficient levels of vitamin B6. That’s why it’s still important to get vitamin B3 from food sources like meat, fish, whole grains, legumes, and fortified cereals.

Deficiency of vitamin B3 causes pellagra, a disease classically marked by the “4 Ds”: dermatitis, diarrhea, dementia, and if untreated, death. The dermatitis appears as a symmetrical, sunburn-like rash, particularly around the neck (“Casal’s necklace”), and is often accompanied by neurological symptoms like confusion, irritability, and memory problems. While rare in well-nourished populations, pellagra still occurs in people with alcohol use disorder, malabsorption, or diets heavily reliant on untreated corn, which contains a form of niacin the body can’t easily absorb.

In high doses, vitamin B3—specifically nicotinic acid—has been used to treat high cholesterol by lowering LDL, reducing triglycerides, and raising HDL. But these benefits are limited by side effects such as flushing, liver toxicity, and insulin resistance, especially with extended-release formulations. Nicotinamide, which does not affect cholesterol, is better tolerated and has shown promise for skin cancer prevention and neuroprotection in disorders like Alzheimer’s and Parkinson’s, as well as rare genetic diseases like NAXD and NAXE deficiencies.

That said, high doses of vitamin B3—especially from supplements—can lead to side effects such as nausea, liver dysfunction, and elevated blood sugar, highlighting the importance of targeted use under medical supervision. Still, when appropriately dosed, vitamin B3 remains a vital component in the foundation of energy metabolism, brain health, and cellular defense.