Our premium L-Arginine stacks Arginine HCI & Arginine Alpha-Ketoglutarate with Citrulline, a precursor to Nitric Oxide (NO) production. We have combined the two best NO forms with Citrulline to provide the ultimate, synergistic blend of the three key Nitric Oxide ingredients to ensure you are getting ALL that Arginine can offer!L-Arginine is an essential amino acid that converts into Nitric Oxide, thereby helping to promote healthy circulation.