Chloride is an essential mineral and electrolyte. You get most of it from table salt, which is sodium chloride. It helps maintain fluid balance, supports nerve signal transmission, and forms hydrochloric acid, the stomach acid you need to digest food.
Most people get enough chloride from their diet, especially through salted foods. You rarely find it as a standalone supplement. Instead, it appears in electrolyte blends or sports drinks to support hydration and recovery after heavy sweating.
People usually take supplemental chloride with water during or after exercise, or as part of a rehydration solution. Very high intake can affect blood pressure, particularly in individuals who are salt sensitive.