L-theanine Supplement Improves Concentration Among Highly Anxious People

Researchers in Japan who studied the effects of the amino acid L-theanine on students with either low or high anxiety ratings found that a daily supplement of the compound may improve concentration among anxious people. Found in tea, L-theanine is “directly or indirectly involved at the neurochemical level and thus it is impacted by a number of neurotransmitter systems,” the researchers wrote. Eighteen healthy participants were divided into two groups, depending on their anxiety levels. Groups received either water alone or water with L-theanine, and were then tested. Highly anxious students who consumed the L-theanine had a slower heart rate, improved attention and better reaction times, compared to the placebo group. One student with low anxiety showed no benefit from the supplement.