Abstract
Vitamin B6 consists of three related pyrimidine vitamer derivatives: pyridoxine, pyridoxal, and pyridoxamine, and their phosphate esters. The metabolically active coenzyme form of vitamin B6 is pyridoxal 5’- phosphate (P5P).1 B6 vitamers are first oxidized to pyridoxal, and rapidly phosphorylated to P5P in the liver.2 P5P is the main circulating form exported from the liver and is considered the most relevant direct measure of vitamin B6 status.