Vitamin B1

Vitamin B1, also called thiamine or thiamin, is one of 8 B vitamins. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which the body uses to produce energy. These B vitamins, often referred to as B-complex vitamins, also help the body metabolize fats and protein. B-complex vitamins are needed for a healthy liver, skin, hair, and eyes. They also help the nervous system function properly and are needed for good brain function.

Source: umm.edu