Vitamin B-1 (Thiamine) is part of the B family of vitamins. It's a water-soluble vitamin, meaning it's not stored in the body and must be replaced regularly. Thiamin is essential for the metabolism of carbohydrates, some amino acids and alcohol. It is needed for the production of the neurotransmitter acetylcholine, and for the detoxification of alcohol and lactic acid (a by-product of strenuous exercise). Thiamin plays an important role in the production of energy.