People over fifty who notice that they have more difficulty concentrating and have a slower work pace than when they were younger improve their cognitive abilities if they drink a cup of matcha daily. This is suggested by a small trial that appeared a few years ago in Nutrients.

Study
In 2021, Japanese researchers published a trial involving 51 volunteers aged 50-69 as participants. The participants were still functioning well mentally, but noticed signs of aging in their memory, work pace, or focus.

The researchers divided the participants into 3 groups.

Participants in a first control group took a placebo daily for 12 weeks. Participants in a second control group took a supplement containing 66 milligrams of caffeine daily.

Finally, participants in the experimental group received a daily supplement containing 2070 milligrams of matcha powder. This supplement contained, among other things, 66 mg of caffeine, 48 milligrams of L-theanine, and 105 milligrams of EGCG.

Click on the table below for a larger version.

Results
The researchers tested their subjects just before supplementation began, after one day of supplementation, and after 12 weeks of supplementation. We can be brief regarding the effects of one day of supplementation. They were not, or barely, significant.

The Japanese researchers did find an effect of 12 weeks of supplementation. They studied their subjects using multiple tests that provided information on memory, information processing, working memory, and emotion recognition, among other things, but they observed no noteworthy shifts on any of those tests.

However, after 12 weeks, the Japanese researchers did find a statistically and clinically significant effect on the Uchida-Kraepelin Test. This test measures the ability to maintain mental focus and a certain work pace during mild stress.

In the Uchida-Kraepelin Test, subjects must solve as many addition problems as possible for half an hour straight. The more problems, the better—but every incorrect answer costs points. Matcha supplementation resulted in an improvement of roughly 15 percent in the average score on the Uchida-Kraepelin Test. That is comparable to an effect size seen in cognitive training.

Without supplements
The capsules that the test subjects took daily contained a total of 2070 milligrams of matcha powder. The researchers therefore did not test extracts, but matcha powder used to make matcha at home.

2070 milligrams is the amount of half a teaspoon. This is enough to make a cup of matcha.

The researchers used matcha powder marketed as Hojin no Shiro. It is a product of ITO EN. The authors of the study were affiliated with the research department of that company. ITO EN therefore also funded the study.