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.

Lakhan and Vieira Nutrition Journal 2010 9:42   doi:10.1186/1475-2891-9-42