L-theanine For Stress, Sleep, Mood, Focus

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Happy 30th anniversary to Stress Awareness Month. In 1992, the month of April was given this designation, and it has been sponsored by the nonprofit Health Resource Network since its inception. In honor of this anniversary, let’s talk about a natural substance that can help us deal with and manage stress: L-theanine.

What is L-theanine?

L-theanine is an amino acid found in both black and green teas as well as some species of mushrooms. Research has shown that L-theanine, whether from food or supplement form, has an ability to help reduce stress and help with related factors such as focus, sleep, brain health, and mood.

Read about the wonders and benefits of black tea

More specifically, L-theanine is able to cross the blood-brain barrier, allowing it to have various effects on the brain. For example, it can impact the activity of neurotransmitters, including those that affect mood (serotonin, dopamine). L-theanine can also alter alpha brain waves and bind to glutamate receptors. All of these abilities of L-theanine have an impact on stress in one form or another.

L-theanine and stress

Managing and reducing stress can provide significant health benefits because unmanaged stress is at the core of many health problems and diseases. In a review of five controlled trials that involved 104 participants, L-theanine was linked with reduced stress and anxiety in four of the trials. 

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In a study of individuals with schizophrenia or schizoaffective disorder, L-theanine (400 mg/d) was given for eight weeks in addition to the patients’ antipsychotic medication. Compared with placebo, the use of L-theanine was associated with a reduction in anxiety.

L-theanine and sleep

Do you get enough quality sleep? Many people don’t, and unmanaged stress is one of the most common reasons for poor sleep. L-theanine may help.

In a double-blind, placebo-controlled study, L-theanine (450-900 mg) or placebo was given to individuals with general anxiety disorder during an eight-week treatment period. Participants who took L-theanine reported “greater self-reported sleep satisfaction than placebo,” although the supplement did not perform better than the placebo for anxiety reduction.

Read about the best teas for brain health

L-theanine and cognitive function

Who doesn’t want better brain health and cognitive function? Could L-theanine help? Some research suggests it can. In a study of individuals with major depressive disorder, 250 mg of L-theanine was added to their current medication treatment for eight weeks. At the end of the study, the participants showed improvement in cognitive function, including verbal memory, executive function, and other factors.

In a review of the health benefits of L-theanine, experts reported that this amino acid appears to have neuroprotective effects, which can improve an individual’s mental health and brain function.

L-theanine and mood

According to psychiatrist Daniel Amen, MD, who authored Change Your Brain, Change Your Life, L-theanine is a nutrient linked to helping with happiness. One reason, he says, is the research showing that L-theanine increases levels of serotonin, dopamine, and GABA (gamma-aminobutyric acid, a mood regulator). An improvement in mood can go hand-in-hand with better sleep and reduced stress and anxiety.

L-theanine and focus

When L-theanine is taken along with caffeine, it may boost attention and the ability to focus. In one study, for example, individuals who took 97 mg of L-theanine and 40 mg of caffeine were better able to focus while doing complex tasks when compared with controls who took a placebo. The combination also reduced feelings of tiredness.

Bottom line

L-theanine is a safe and effective natural remedy to help manage stress and sleep problems associated with stress and anxiety, as well as improve brain function and focus. Enjoying a cup or two of green or black tea daily is a relaxing way to get L-theanine in your life, as are supplements.

Everett JM et al. Theanine consumption, stress and anxiety in human clinical trials: a systematic review. Journal of Nutrition & Intermediary Metabolism 2016; 4:41-42
Giesbrecht T et al. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutritional Neuroscience 2010 Dec; 13(6):283-90.
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Hidese S et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatrica 2017 Apr; 29(2):72-79. 
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Deborah is a freelance health writer who is passionate about animals and the environment. She has authored, co-authored, and written more than 50 books and thousands of articles on a wide range of topics. Currently, she lives in Tucson, Arizona.