Areas of Focus:

Cognitive enhancement (memory and speed improvement) 

Study Type:

Randomised placebo controlled study

Journal Publication:

National Library Of Medicine / National Centre Of Biotechnology information

Link To Study: 


This study looked at how l-theanine, an amino acid, found in green tea, affects brain function in older Japanese adults. They wanted to see if it could improve memory and thinking skills. They did a careful study where some people took l-theanine and others took a fake pill without knowing which they were taking.

They tested their memory and thinking before and after taking l-theanine for 12 weeks. They found that taking l-theanine once improved attention and made people faster at certain tasks. After 12 weeks, it also helped people remember things better and made fewer mistakes in memory tasks. This suggests that l-theanine might be helpful for attention, memory, and thinking skills, especially in older adults.