BH-4 PTERDIDIN 2.5mg 60 caps (BH-4) LWTI

WE highly recommend overnight shipping for BH4 during the warmer months because this is a heat sensitive item.

Tetrahydrobiopterin or BH4 is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide synthases