Vitamins are nutrients required for essential metabolic reactions in the body catalysts and participants in the chemical reaction. The body typically assembles vitamin-dependent catalysts from a variety of building blocks including amino acids, sugars, phosphates, and vitamins. Each vitamin is typically used in multiple different catalysts and therefore has multiple functionsnervous system maintains a feeling of normalcy across a wide range of vitamin dosages.

Vitamins have only been produced as commodity chemicals and made widely available as inexpensive pills for a few decades[ Vitamin ]