Used primarily to treat thiamine (vitamin B1) deficiency, especially in cases of beriberi and Wernicke-Korsakoff syndrome. It is more effective than water-soluble thiamine due to its fat-soluble nature, allowing better absorption and longer retention in the body. Commonly used in Japan and some Asian countries for managing symptoms related to chronic fatigue, neuritis, and neurological disorders linked to low thiamine levels. Also found in dietary supplements aimed at improving energy metabolism and nerve function. Frequently prescribed in patients with poor nutritional intake, alcohol dependence, or malabsorption conditions.