L-arginine therapy in Raynaud's phenomenon?

Since L-Arginine is the substrate for nitric oxide synthesis by vascular endothelial cells the effects of L-arginine treatment on the digital vascular response to local stimuli were investigated in patients with primary or secondary Raynaud's phenomenon. After therapy, patients with Raynaud's phenomenon secondary to systemic sclerosis showed: (1) higher digital vasodilation after local warming, (2) cold-induced digital vasodilation, and (3) increase of plasma levels of tissue-type plasminogen activator.