Nicotinic acid, also known as niacin or vitamin B3, is a water-soluble vitamin that plays a crucial role in the body's metabolism. It helps convert food into energy and is essential for the proper functioning of the nervous system, digestive system, and skin health. Nicotinic acid can be found in various foods, including meat, fish, eggs, and green leafy vegetables. In addition to its dietary importance, nicotinic acid is used in medicine to help manage cholesterol levels. It can lower bad cholesterol (LDL) and increase good cholesterol (HDL), contributing to heart health. However, high doses should be taken under medical supervision due to potential side effects.