A preliminary study suggests that L-arginine, when combined with L-lysine, can help to reduce anxiety symptoms in subjects who have performance anxiety when speaking in public (Jezova et al., 2005). More studies are needed to confirm this preliminary finding.
Subchronic treatment with amino acid mixture of L-lysine and L-arginine modifies neuroendocrine activation during psychosocial stress in subjects with high trait anxiety. Jezova D, Makatsori A, Smriga M, Morinaga Y, Duncko R. Nutr Neurosci. 2005 Jun;8(3):155-60.