The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness.
The non-proteinic amino acid L-theanine and caffeine, a methylxanthine derivative, are naturally occurring ingredients in tea. The present study investigated the effect of a combination of 97 mg L-theanine and 40 mg caffeine as compared to placebo treatment on cognitive performance, alertness, blood pressure, and heart rate in a sample of young adults (n = 44). Cognitive performance, self-reported mood, blood pressure, and heart rate were measured before L-theanine and caffeine administration (i.e. at baseline) and 20 min and 70 min thereafter. The combination of moderate levels of L-theanine and caffeine significantly improved accuracy during task switching and self-reported alertness (both P < 0.01) and reduced self-reported tiredness (P < 0.05). There were no significant effects on other cognitive tasks, such as visual search, choice reaction times, or mental rotation. The present results suggest that 97 mg of L-theanine in combination with 40 mg of caffeine helps to focus attention during a demanding cognitive task.
Sensation, Perception, and Behaviour, Unilever R&D, Vlaardingen, The Netherlands. Timo.Giesbrecht@unilever.com
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T
Giesbrecht
J A
JA
Rycroft
M J
MJ
Rowson
E A
EA
De Bruin
D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D001288:Attention / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002110:Caffeine / Q000008:administration & dosage*; D003071:Cognition / Q000187:drug effects*; D004311:Double-Blind Method; D005221:Fatigue; D005260:Female; D005971:Glutamates / Q000008:administration & dosage*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D010919:Placebos; D011930:Reaction Time; D013662:Tea / Q000737:chemistry
D005971:Glutamates; D010919:Placebos; D013662:Tea; D002110:Caffeine; C026166:theanine