In order for vitamin B6 (pyridoxine) to be utilized by the body it must first be converted into its active coenzyme form - Pyridoxal-5-phosphate or P5P. It is primarily in the liver that P5P is synthesized from pyridoxine. P5P is associated with numerous enzymes, many of which are involved in amino acid metabolism. This necessary process produces the neurotransmitters dopamine, nor adrenalin, GABA and cartooning, as well as the hemoglobin in red blood cells. Many B6 supplements on the market are the inactive pyridoxine HCL form. In some cases supplementation of this form singularly, caused a reversible numbness & tingling of the extremities. In doses as low as 200 mg daily over a 3-year period. This problem was thought to be secondary to the liver's inability to convert this form into the useable P5P form. Using P5P avoids this problem.