A vital water-soluble vitamin converted into NAD+/NADP+ coenzymes for ATP production, cellular repair, and skin barrier health.
What it is
Vitamin B3 is an essential water-soluble B vitamin comprising nicotinic acid, nicotinamide (niacinamide), and nicotinamide riboside. In nutritional supplements, nicotinamide is widely favored because it provides complete vitamin B3 coenzyme activity without triggering cutaneous vasodilation or flushing. Niacin serves as the essential metabolic precursor for nicotinamide adenine dinucleotide (NAD+) and NADP+, pyridine nucleotide coenzymes that govern cellular respiration, redox reactions, and sirtuin-mediated DNA repair.
Also known as: Niacinamide, Nicotinamide, Vitamin B3
What it does
- Serves as the precursor for NAD+ and NADP+, driving mitochondrial ATP synthesis.
- Supports cellular energy release from carbohydrates, fats, and proteins.
- Promotes skin barrier integrity, vascular health, and central nervous system function.
- Facilitates enzymatic DNA repair through PARP and sirtuin pathway signaling.
Amplified by probiotics
Absorption of vitamin B3 occurs in the small intestine via sodium-dependent and proton-coupled carrier-mediated mechanisms. Probiotic bacteria—including select Lactobacillus and Bifidobacterium strains—synthesize nicotinic acid and nicotinamide via the de novo tryptophan and salvage pathways. Microencapsulated probiotics ensure sustained delivery to the distal gut, where local microbial niacin production fuels colonic enterocyte energetics. Niacin binds colonic GPR109A receptors, suppressing intestinal mucosal inflammation, enhancing tight junction protein synthesis, and promoting IL-10 secretion. Probiotics and B3 thus synergistically bolster epithelial barrier defense, mucosal integrity, and systemic NAD+ pools.
Typical dose
16–50 mg/day
The evidence
Evidence: strongDecades of clinical trial data prove that vitamin B3 is essential for human energy metabolism, DNA repair, and lipid modulation. Clinical studies confirm nicotinamide restores cellular NAD+ levels and supports epithelial health without flushing (Kirkland 2012, Mutat Res; Bogan & Brenner 2008, Annu Rev Nutr).
Safety & who should check first
Tolerable Upper Limit for nicotinamide is 900 mg/day in adults (35 mg/day for nicotinic acid to prevent flushing). Safe during pregnancy and lactation at dietary intake levels.