While these are interesting findings, there are not a lot of conclusions that can be drawn from this alone. It was a small, short study, and most people likely aren’t choosing to consume caffeine minutes before going to bed. 

But putting these findings in the context of what we already know about L-theanine can help you time out when you should ingest these compounds for optimal productivity and sleep. 

L-theanine is a powerful phytochemical that is shown to influence alpha brain waves2—the same brain bandwidth that promotes relaxation (without drowsiness).* 

And while this compound can promote restfulness before bed, it can also help calm feelings of anxiousness3 and supports a resilient response to stress3 during the day.*

Caffeine is also best consumed earlier, and most experts recommend having a strict cutoff time for caffeine—approximately six hours before you go to bed. 

So to really reap the calm energy that these two ingredients provide, it’s best to drink your green tea or matcha before late afternoon. And if those beverages aren’t your thing, that’s ok. Some nootropics like mindbodygreen’s focus+ contain both.