Yes your body develops a tolerance to consistent L-Arginine use. We all know Arg gets metabolized to become Nitric Oxide. Within the human body there is a nasty free radical lurking about. This free radical is called Super Oxide. When super oxide comes in contact with NO they react to form a few new compounds. Among these new compounds is another nasty free radical known as Peroxynitate. The more arginine you consume, the more NO is produced, which mean more peroxynitrate is produced. If enough peroxynitrate is present your body, your body stops breaking down arginine into NO. So you must quench all the oxides [including peroxynitrate] that are formed from constant Arg supplementation. A couple antioxidants that are good to eliminate these oxides are the 2 most important OPC[Oligomeric Proanthocyanidins], resveratrol and EGCG. A couple more good antioxidants that well help are gamma tocopherol and NAC. Resveratrol also stimulates the production of iNos[inductible Nitric Oxide Synthase]; the enzyme responsible for NO production.