Niacin powder with flushing by BulkSupplements.com is one of the selections from our vitamin supplements. Niacin is also known as Vitamin B3 and its an important vitamin and it's one of the eight B vitamins.* This product may cause flushing. Each serving of this product contains 500mg of Vitamin B3, as Niacin form, which is about 1/5 tsp and may need an accurate milligram scale to measure. And, we also sell it different sizes ranging from 100g to 5kg in resealable bags. Contents of this product is sold by weight, not volume and settling may occur. Our Niacin powder, or Vitamin B3 powder, is pure, natural and does not contain any fillers, additives, and artificial flavors. And this Vitamin B3 powder is dairy free, gluten free, soy free, yeast free, and no added sugar. All products by BulkSupplements.com are manufactured according to cGMP Standards to ensure the highest quality for manufacturing, packaging, labeling, and holding operations. We work with a third-party laboratory that test our products at multiple stages during production, from raw material to finished products, and ensures compliance, standards, and consistency.