Table 5.

Trials testing lysine

Reference	Study Design	Sample Population	Intervention	Control	Length of Treatment	Outcomes	Direction of Evidence	Reported Adverse Events
Jezova (2005) [67]	Randomized; Double-blind; Parallel Group	29 healthy male subjects at the upper limit of the normal range of a trait anxiety scale1	Mixture of L-lysine and L-arginine (3 g each/day)	Placebo	10 days	AMino acid treatment enhanced adrenocorticotropic hormone, cortisol, adrenaline and noradrenaline levels and galvanic skin responses during stress; no effect on heart rate and blood pressure.	+	None
Smriga (2007) [68]	Randomized; Double-blind; Parallel Group	108 healthy Japanese adults	Oral L-lysine (2.64 g/day) and L-arginine (2.64 g/day)	Placebo	1 week	L-lysine/L-arginine treatment significantly reduced trait and state anxiety; also decreased basal levels of salivary cortisol and chromogranin-A in male subjects	+	None

STAI: State Trait Anxiety Inventory.

1. Scored above 45 on STAI questionnaire.