HTS code 2936.29.20.00 covers "Provitamins and vitamins, natural or reproduced by synthesis (including natural concentrates), derivatives thereof used primarily as vitamins, and intermixtures of the foregoing, whether or not in any solvent › Other vitamins and their derivatives › Niacin and niacinamide › Aromatic or modified aromatic" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.