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New Study Shows L

Nov 30, 2023

Caffeine is often used to help us power through our days and sometimes (regrettably) nights. And tea is one of the most popularly consumed, and naturally caffeinated, drinks worldwide. Green tea also contains a calming compound that helps counter caffeine’s jitteriness: L-theanine.*

Researchers of a recent small study1 in Japan conducted (a bit of an odd) experiment to see whether L-theanine improved worsened sleep quality from caffeine in college-aged students.

Here’s what you need to know.

Sustained daily energy and focus, minus the crash*


Researchers created four different beverages for each of the participants to try: one with 50 milligrams of L-theanine, one with 30 milligrams of caffeine, one with both, and a placebo.

Each person consumed each beverage once and then waited a week before continuing with the next. And here’s the kicker, they consumed it 10:50 pm—10 minutes before going to bed.

They had electrodes attached to the scalp to measure sleep stage and brain wave activity and underwent brain imaging each night of the study (four total).

After all this, there was one sign that L-theanine may combat some of caffeine's detriment on sleep. Specifically, drinking the caffeine and L-theanine beverage significantly reduced the total number of minutes people spent awake after initially falling asleep compared to just the caffeine.

Even compared to the placebo and L-theanine drinks alone, the combined one was linked to the least amount of wakefulness minutes (although these comparisons were not statistically significant and could have happened by chance).

Other measures of sleep (like total time asleep, time it took to fall asleep, etc.) were not significant between any of the groups.

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.

focus+ offers premium sourcing and quality of ingredients at their full-potency, clinically researched doses—including 100 milligrams of L-theanine (as Suntheanine®) in addition to 150 milligrams of instant- and sustained-release caffeine from antioxidant-rich botanicals.

Plus additional botanicals and bioactives (i.e., Panax ginseng, and guarana seed extract) and essential vitamin B12 (in its bioactive methylcobalamin form) to help provide mental clarity, focused calmness, and a bright mood lift to help you tackle to-dos productively.*

While focus+ can be taken any time of day, the same at least six hours before bed guideline, applies due to the caffeine content.

Optimizing sleep and caffeine intake is top of mind in today’s hectic world. And while it’s well established that caffeine is stimulatory and L-theanine is calming, the degree to which L-theanine by counter caffeine’s energizing impact is not clear.*

While researchers continue to parse out that question, it’s still best to take in green tea or supplement with these ingredients long before you hit the hay.

Sustained daily energy and focus, minus the crash*


Molly Knudsen, M.S., RDN is a Registered Dietician Nutritionist and mindbodygreen's supplements editor. She holds a bachelor’s degree in nutrition from Texas Christian University and a master’s in nutrition interventions, communication, and behavior change from Tufts University. She lives in Boston, Massachusetts and enjoys connecting people to the food they eat and how it influences health and wellbeing.