A research study of the acute effects of L-Theanine, Caffeine, and L-Theanine + Caffeine combination on attention
One of the best studied nootropic regimens consists of the combination of caffeine and L-theanine. In isolation, caffeine has been shown in a multitude of studies to enhance alertness and improve cognitive performance. By contrast, L-theanine has been shown to exert anti-stress and pro-relaxation benefits...with inconsistent evidence for an independent effect on attention.
However, multiple studies have demonstrated that when used together, the combination possesses a unique cognitive enhancement profile. In one study, the authors directly compared caffeine, L-theanine, caffeine + L-theanine, black tea, and water on behavioral measures of attention and on N2-P300, an electroencephalogram measurement associated with increased attention (electroencephalograms measure electrical signals generated by the brain).
The authors used a task wherein a red or white flash of light briefly appear on a computer screen, and subjects must press a button in response to the red light and not the white. It was found that the combination of caffeine and L-theanine significantly reduced the reaction time to respond, to a greater extent than caffeine or L-theanine alone. In addition, caffeine and the combination of caffeine and L-theanine trended towards an increase in correct responses (caffeine: p-value = 0.07 and caffeine + L-theanine: p-value= 0.08), with the combination of caffeine and L-theanine exhibiting a greater mean improvement in correct responses (caffeine = 4.0 and caffeine + L-theanine = 4.5). With regards to the N2-P300 signal, the combination of caffeine + L-theanine demonstrated the biggest enhancement of this signal, while caffeine and L-theanine also significantly enhanced the N2-P300, but to a lesser extent than the combination.
Overall, this data builds on the evidence that the nootropic combination of caffeine and L-theanine can significantly improve attentional capacity, more than when used individually. In particular, this improvement can be seen in isolated tests of attention, as well as at the level of electrophysiology (the electrical signal produced by the brain). Consider adding caffeine + L-theanine into your daily nootropic regimen for acute enhancement of attention.
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