Used to treat and prevent vitamin B1 deficiency, especially in people with poor diet, certain illnesses, or alcohol use disorder. Commonly prescribed for conditions like beriberi, which affects the nerves and heart, and Wernicke-Korsakoff syndrome, a brain disorder linked to severe deficiency. Also supports normal nerve, muscle, and heart function. Often added to fortified foods and used in dietary supplements to maintain overall metabolic health. Plays a role in carbohydrate metabolism by helping convert nutrients into energy. Used in some cases to support recovery in patients with nerve inflammation or digestive issues related to nerve control.