Niacin

Niacin or vitamin B3 is used to turn food into energy, and helps keep the nervous system, digestive system and skin healthy. Niacin may be bought over the counter, or used in higher doses on prescription for high cholesterol or in combination with niacinamide to treat pellegra (niacin deficiency). Niacin is comprised of nicotinic acid and nicotinamide. Niacinamide and nicotinamide are water soluble B3.

There are two co-enzyme forms: nicotinamide dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). Both play an important role in energy transfer reactions in the metabolism of glucose, fat and alcohol.

Nicotinamide dinucleotide (NAD)
NAD carries hydrogens and their electrons during metabolic reactions, including the pathway from the citric acid cycle to the electron transport chain. NADP is a coenzyme in lipid and nucleic acid synthesis.

Risks and safety
Niacin is generally considered safe, but side effects may sometimes occur and may be serious. Side effects are more likely in prescription strength doses, e.g., 2,000-6,000mg per day. Side effects may include:
 * Severe skin flushing with dizziness
 * Rapid heartbeat (tachycardia)
 * Itching
 * Nausea and/or vomiting
 * Abdominal pain
 * Diarrhea
 * Gout
 * Liver damage
 * Diabetes
 * Worsening allergies
 * Increased thyroid symptoms
 * Low blood pressure

Cost and availability
Niacin and nicotinamide are available over the counter or on prescription. NAD is available over the counter.

Learn more

 * Niacin - Linus Pauling Institute Micronutrient Information Center
 * Niacin - drugs.com
 * Nicotinamide - Memorial Sloan Kettering Center Center