Areas of Focus:

Cognitive enhancement & thinking

Study Type:

Blind Placebo 

Journal Publication:

National Library Of Medicine/National Centre For Biotechnology Information

Link To Study: 



This study wanted to see how caffeine and L-theanine, a substance found in green tea, affect thinking and mood in healthy people. They compared the effects of taking 50 mg of caffeine alone, or with 100 mg of L-theanine, to a fake pill in 27 participants. They measured people's performance on memory tasks, attention tasks, and mood before and after each treatment.

They found that caffeine alone made people feel more alert after 60 minutes and improved their attention after 90 minutes. When combined with L-theanine, it made people faster and more accurate at attention tasks after 60 minutes, and it helped them ignore distractions during memory tasks after both 60 and 90 minutes. This suggests that combining L-theanine and caffeine might be helpful for improving performance on tasks that require a lot of thinking.