A coenzyme in many amino acid enzyme reactions, Vitamin B6 is also essential to enzymatic processes in both glucose and lipid metabolism. The active form of Vitamin B6 is also integral to many functions of macronutrient metabolism, hemoglobin synthesis, histamine synthesis, neurotransmitter synthesis, and gene expression. This essential vitamin is typically metabolized in the liver, and is a cofactor in the biosynthesis of the five most important neurotransmitters: serotonin, dopamine, epinephrine, norepinephrine, and gamma-aminobutyric acid. Numerous foods contain high concentrations of vitamin B6 in both bound and free forms, and is primarily found in pork, turkey, beef, bananas, pistachios, chickpeas, and potatoes. The daily recommended intake for B6 is 1-1.3 mg per day for women and 1.1-1.4 mg for men. Daily value for most dietary supplements is currently set at 1.7 mg per day within the United States.