The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (over 18 years old)
Taking niacin with food may reduce stomach upset and the risk of stomach ulcers. Doses usually start low and are gradually increased to minimize the common side effect of skin flushing. Taking aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) at the same time during the first one to two weeks may reduce this flushing. Use of an antihistamine 15 minutes prior to a niacin dose may also be helpful. The flushing response may decrease on its own after one to two weeks of therapy. Extended release niacin products may cause less flushing than immediate release (crystalline) formulations, but may have a higher risk of stomach upset or liver irritation. In general, not all niacin products are equivalent. Patients switching from one product to another may have an increase or decrease in side effects.
The dietary reference intake established by the Food and Nutrition Board for niacin (in the form of niacin equivalents, 1 milligram niacin = 60 milligrams tryptophan) ranges from 14 to 18 milligrams daily for adults, with a maximum intake of 35 milligrams daily. 50 milligrams to 6 grams has been taken in divided doses for other conditions based on physician and pharmacist recommendations.
Niacinamide (nicotinamide) and niacin (nicotinic acid) are used in cosmetics, as well as hair and skin conditioning agents. The concentration of niacinamide varies from a low of 0.0001% in night preparations to a high of 3% in body and hand creams, lotions, powders, and sprays. Niacin concentrations range from 0.01% in body and hand creams, lotions, powders, and sprays to 0.1% in paste masks (mud packs). For skin conditions, 2-5% niacinamide cream has been used.
Niacin dosing may vary according to the condition it is being used to treat. In clinical studies, doses have included 500 milligrams (single dose) for age-related macular degeneration, 375 milligrams (single dose) for hyperphosphatemia, up to 1 gram daily for pellagra, up to 3 grams daily for diabetes, up to 3 grams daily for osteoarthritis, and up to 6 grams daily (either along or combined with other agents) for cardiovascular disease.
Children (under 18 years old)
There is not enough scientific evidence to recommend the safe use of niacin or niacinamide in children. Niacinamide has been studied in children at daily doses of approximately 150 to 300 milligrams per year of the child's age (up to 3 grams), or 20-40 milligrams per kilogram daily, for the prevention of type 1 diabetes mellitus in "high-risk" individuals. There is a lack of reported serious side effects, and safety and effectiveness are not clear. Patients should speak with a qualified healthcare provider if considering this therapy.