Vitamin B6, or pyridoxine, is a component of the vitamin B complex and necessary for optimal health. In its active form, pyridoxal 5-phosphate (PLP), vitamin B6 is a cofactor in more than 160 enzyme-driven reactions in the body that affect amino acid transformation, synthesis and breakdown of neurotransmitters, cellular energy production and use, immune function, methylation and DNA synthesis and repair. While most people get enough B6 from food sources, some people are B6 deficient. Optimal blood levels of PLP may help support cardiovascular and neurological health. Through its role as a methylator, vitamin B6 (along with B12 and folate) helps maintain homocysteine levels already within the normal range. One study noted a connection between vitamin B6 levels, high homocysteine levels and increased mortality.