VITAMIN B1 INJECTION provides the essential vitamin Thiamine. How Does It Work?Thiamine (Vitamin B1) plays an important role in the metabolism of carbohydrates, and energy production for all cells. Thiamine is most important in the breakdown of pyruvic acid, a waste product in hard working muscles, along with lactic acid. In any situation where carbohydrates are the major energy source, or when glucose is added to the diet, thiamine requirement is increased significantly. Thiamine is essential as part of the coenzyme which is involved in the breakdown of glucose for energy.