Powerful Amino Acids Lysine and Arginine May Reduce Stress and Anxiety

By VRP Staff

L-arginine and L-lysine both appear to affect the nervous and endocrine systems of subjects suffering from stress and anxiety, a recent study indicates.

In the study, researchers examined the effects of L-lysine and L-arginine on healthy subjects with relatively high trait anxiety who were exposed to social stress. In the randomized, double-blind, placebo controlled trial, 29 healthy subjects at the upper limit of the normal range of an anxiety scale were given a mixture of L-lysine and L-arginine (3 grams each per day) for 10 days. The subjects were then asked to engage in public speaking in order to expose them to a social stress experience. Hormone levels, cardiovascular activation and skin conductance were measured.

Treatment with the two amino acids improved the way the body reacted to stress. Subjects treated with L-arginine and L-lysine experienced an improvement in levels of adrenocorticotropic hormone (a hormone that plays an important role in the function of the adrenal glands). They also experienced improvements in cortisol, adrenaline and noradrenaline levels. Galvanic skin responses (the measurement of the change in the electrical resistance of the skin in response to emotional stimuli) also was positively affected by the two amino acids during stress compared to the placebo. Increases in the heart rate and blood pressure in response to public speaking were not influenced by amino acid treatment.

According to the researchers, “Results of the present study support the hypothesis that L-lysine in combination with L-arginine, which may induce anxiolytic [anti-anxiety] effects, modify hormonal responses during psychosocial stress in humans.”

The study authors went on to state that the two amino acids may work by normalizing hormone levels to that observed in subjects who don’t suffer from anxiety.

Reference:

Jezova D, Makatsori A, Smriga M, Morinaga Y, Duncko R. Subchronic treatment with amino acid mixture of L-lysine and L-arginine modifies neuroendocrine activation during psychosocial stress in subjects with high trait anxiety. Nutr Neurosci. 2005 Jun;8(3):155-60.