What is L-Theanine?

L-theanine, also known simply as theanine, is an amino acid primarily found in green tea.((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))Black tea and certain mushrooms also contain small amounts of this amino acid.((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.)) Theanine is also sold as a supplement, often in pill or tablet form.

According to research and experts, L-theanine offers numerous benefits related to the brain. Among these are:

• Relaxation without drowsiness; ((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Hidese, Ogawa, Ota, Ishida, Yasukawa, Ozeki, and Kunugi. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.” Nutrients 11 (10): 2362. https://doi.org/10.3390/nu11102362.))
• Improved sleep and reduced risk of insomnia; ((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Kim, Suhyeon, Kyungae Jo, Ki-Bae Hong, Sung Hee Han, and Hyung Joo Suh. 2019. “GABA and L-Theanine Mixture Decreases Sleep Latency and Improves NREM Sleep.” Pharmaceutical Biology 57 (1): 64–72. https://doi.org/10.1080/13880209.2018.1557698.))
• Reduced stress and improved ability to overcome it; ((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Hidese, Ogawa, Ota, Ishida, Yasukawa, Ozeki, and Kunugi. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.” Nutrients 11 (10): 2362. https://doi.org/10.3390/nu11102362.))
• Better focus ((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Hidese, Ogawa, Ota, Ishida, Yasukawa, Ozeki, and Kunugi. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.” Nutrients 11 (10): 2362. https://doi.org/10.3390/nu11102362.))

Some research suggests that L-theanine can normalize blood pressure and strengthen our immune system––the body’s natural defense against external threats. ((Yoto, Ai, Mao Motoki, Sato Murao, and Hidehiko Yokogoshi. 2012. “Effects of L-Theanine or Caffeine Intake on Changes in Blood Pressure under Physical and Psychological Stresses.” Journal of Physiological Anthropology 31 (1). https://doi.org/10.1186/1880-6805-31-28.))((Juszkiewicz, A., A. Glapa, P. Basta, E. Petriczko, K. Żołnowski, B. Machaliński, J. Trzeciak, K. Łuczkowska, and A. Skarpańska-Stejnborn. 2019. “The Effect of L-Theanine Supplementation on the Immune System of Athletes Exposed to Strenuous Physical Exercise.” Journal of the International Society of Sports Nutrition 16 (1). https://doi.org/10.1186/s12970-019-0274-y.))

Alpha Waves: What Are They and What Makes Them So Important?

It might come to you as a surprise, but your brain is bursting with electric activity. Every second, countless signals travel between the billions of neurons inside your brain, allowing you to think, feel, learn, remember, control your muscles, and stay alive.

A brain wave refers to a group of neurons sending a synchronized message to another group of neurons. The term ‘wave’ comes from the fact that when an electroencephalogram (EEG) test measures electrical activity in the brain, results come in the shape of wave patterns on a long sheet of paper.

Depending on the speed, brain waves come in five broad categories. Gamma waves are the quickest at a frequency of 35 Hz or more. In contrast, Delta are the slowest at a mere 0.5 to 4 Hz. Alpha waves are somewhere in the middle with a frequency of 8 to 12 Hz—and research links these waves to relaxation.((“Brain Waves – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/brain-waves.))

The mind produces alpha waves during waking hours, but only when we aren’t focusing on any specific thing. For example, when you’re driving down the highway in low traffic hours and listening to music, your mind is somewhat engaged but you’re not asking it to process a lot of information or solve issues. As a result, your brain produces more alpha waves.

In contrast, take the same car in an urban setting during rush hour, and you will no longer be in the same relaxed state. Instead, your brain will produce more gamma and beta waves, which are linked to concentration and anxiety.

Alpha waves are essential because they promote relaxation and allow us to tackle stress, leading us to feel more at ease and in control of ourselves. Some research also finds that boosting alpha wave levels can lead to creativity, which makes sense. It’s difficult to be creative under stress, but give your mind some time to relax, and you can come up with numerous amazing ideas.

How Does L-Theanine Supplementation Impact Alpha Waves in the Brain?

In one paper from 2001, eloquently titled “200 mg of Zen,” the author argues that L-theanine is largely responsible for tea’s relaxing and soothing effects on the mind. ((Mason, Russ. “200 Mg of Zen: L-Theanine Boosts Alpha Waves, Promotes Alert Relaxation.” Alternative and Complementary Therapies, vol. 7, no. 2, 2001, pp. 91–95., https://doi.org/10.1089/10762800151125092.)) Doctor Russ Mason, a specialist in diagnosing, managing, and treating multiple sclerosis, puts forth numerous compelling arguments favoring L-theanine as a source of relaxation and mindfulness.

In the papers he reviews, researchers note that participants begin to feel more relaxed 30 to 40 minutes after ingesting L-theanine. The amino acid promotes alpha wave production, leading to better concentration and relaxation without drowsiness.

One paper from 2013 exhibited similar findings. ((Lardner, Anne L. 2013. “Neurobiological Effects of the Green Tea Constituent Theanine and Its Potential Role in the Treatment of Psychiatric and Neurodegenerative Disorders.” Nutritional Neuroscience 17 (4): 145–55. https://doi.org/10.1179/1476830513y.0000000079.)) In it, 35 young participants were split into two groups:

• L-theanine – 16 of the participants took 50 mg of L-theanine
• Placebo – 19 were given a placebo

EEG recordings tracked brain wave activity at several periods between 45 and 105 minutes after ingestion. The values were compared to baselines. Researchers found significant increases in alpha wave activity in the L-theanine group compared to the placebo group and concluded:

“These data indicate that L-theanine, at realistic dietary levels, has a significant effect on the general state of mental alertness or arousal.”

The Direct Benefits of L-Theanine and Its Impact on Alpha Waves

Okay, so, L-theanine supplementation promotes alpha wave activity. But what do these effects mean in a practical sense? Do they offer any notable benefits?

The most notable benefit of improved alpha wave activity is that we can better achieve and maintain a flow state.((Katahira, Kenji, Yoichi Yamazaki, Chiaki Yamaoka, Hiroaki Ozaki, Sayaka Nakagawa, and Noriko Nagata. 2018. “EEG Correlates of the Flow State: A Combination of Increased Frontal Theta and Moderate Frontocentral Alpha Rhythm in the Mental Arithmetic Task.” Frontiers in Psychology 9 (March). https://doi.org/10.3389/fpsyg.2018.00300.)) Alpha waves promote a calm but not drowsy state of mind, making it easier to concentrate on tasks. The flow state, also known as being in the zone, is profoundly beneficial because it leads to better productivity, makes us enjoy the task we are doing, and prevents us from wasting time as we jump from one thing to the next.

Another benefit of L-theanine and the amino acid’s impact on brain wave activity is that it improves our cognitive abilities, making it easier to study and retain information((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Baba, Yoshitake, Shun Inagaki, Sae Nakagawa, Toshiyuki Kaneko, Makoto Kobayashi, and Takanobu Takihara. 2021. “Effects of L-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study.” Journal of Medicinal Food 24 (4): 333–41. https://doi.org/10.1089/jmf.2020.4803.)). In one paper from 2019, 30 healthy people were assigned to one of four groups ((Hidese, Ogawa, Ota, Ishida, Yasukawa, Ozeki, and Kunugi. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.” Nutrients 11 (10): 2362. https://doi.org/10.3390/nu11102362.)):

• 200 mg L-theanine daily
• Placebo

Both protocols lasted for four weeks, and researchers examined measures of sleep latency (the time it took folks to fall asleep), self-rated depression, anxiety, and overall cognition. Measures of sleep quality, depression, and anxiety saw improvements in the L-theanine group. Additionally, subjects that took L-theanine saw improvements in speaking ability and executive function.

The third massive benefit of L-theanine supplementation is that it can help us sleep better because the compound contributes to several changes in the brain. ((“Theanine – an Overview | ScienceDirect Topics.” n.d. Www.sciencedirect.com. https://www.sciencedirect.com/topics/neuroscience/theanine.))((Kim, Suhyeon, Kyungae Jo, Ki-Bae Hong, Sung Hee Han, and Hyung Joo Suh. 2019. “GABA and L-Theanine Mixture Decreases Sleep Latency and Improves NREM Sleep.” Pharmaceutical Biology 57 (1): 64–72. https://doi.org/10.1080/13880209.2018.1557698.)) A notable reason for the effect is that L-theanine increases alpha wave levels, leading to wakeful relaxation. As a result, we feel more at ease and less stressed, contributing to a healthy sleep latency.

Another reason for L-theanine’s favorable impact on sleep is that it can raise levels of essential neurotransmitters in the brain:

• gamma-Aminobutyric acid (GABA) – an inhibitory neurotransmitter of the central nervous system;((Gottesmann, Claude. 2002. “GABA Mechanisms and Sleep.” Neuroscience 111 (2): 231–39. https://doi.org/10.1016/s0306-4522(02)00034-9.))

• Serotonin – a neurotransmitter and chemical precursor to melatonin, a hormone your brain produces in response to darkness, promoting sleep;((Zhao, Dake, Yang Yu, Yong Shen, Qin Liu, Zhiwei Zhao, Ramaswamy Sharma, and Russel J. Reiter. 2019. “Melatonin Synthesis and Function: Evolutionary History in Animals and Plants.” Frontiers in Endocrinology 10: 249. https://doi.org/10.3389/fendo.2019.00249.))

• Dopamine – a neurotransmitter with essential functions related to cognition, mood, and the prevention of insomnia. ((Monti, Jaime M., and Daniel Monti. 2007. “The Involvement of Dopamine in the Modulation of Sleep and Waking.” Sleep Medicine Reviews 11 (2): 113–33. https://doi.org/10.1016/j.smrv.2006.08.003.))

These benefits suggest that L-theanine supplementation can improve a person’s life on many fronts. Improved cognition and reduced anxiety promote better productivity, success at work, and personal fulfillment. Similarly, better sleep has countless positive effects on your health, well-being, and fitness efforts.

Are There Other Supplements with Similar Effects on the Mind?

Plenty of compounds have calming effects on the mind and central nervous system. Notable examples include melatonin, ashwagandha, and valerian. The problem with these is that each can lead to drowsiness.

As briefly mentioned above, melatonin is a hormone the body produces in response to darkness, promoting relaxation and helping us fall asleep. Melatonin exists in supplement form, which people can take before bedtime to promote relaxation and sleep.

Ashwagandha is a popular nootropic supplement claimed to help us deal with stress and anxiety. One proposed mechanism is that the compound can repair neurons damaged from stress. The nootropic can also promote sleep, likely due to its favorable effects on stress levels.((Langade, Deepak, Subodh Kanchi, Jaising Salve, Khokan Debnath, and Dhruv Ambegaokar. 2019. “Efficacy and Safety of Ashwagandha (Withania Somnifera) Root Extract in Insomnia and Anxiety: A Double-Blind, Randomized, Placebo-Controlled Study.” Cureus, September. https://doi.org/10.7759/cureus.5797.)) But, as far as alpha waves go, no research suggests that ashwagandha can promote similar effects to L-theanine.

Finally, we have valerian root––a natural sleep aid for people struggling with insomnia. Like ashwagandha, the compound can promote relaxation, but the effects don’t appear to be linked to brain wave activity.((Bent, Stephen, Amy Padula, Dan Moore, Michael Patterson, and Wolf Mehling. 2006. “Valerian for Sleep: A Systematic Review and Meta-Analysis.” The American Journal of Medicine 119 (12): 1005–12. https://doi.org/10.1016/j.amjmed.2006.02.026.))

Certain essential nutrients, including magnesium and zinc, are also linked to stress resilience and relaxation. For example, magnesium can help us relax by blocking stimulating neurotransmitters in the brain and binding to calming receptors. ((Boyle, N, C Lawton, and L Dye. 2017. “The Effects of Magnesium Supplementation on Subjective Anxiety and Stress—a Systematic Review.” Nutrients 9 (5): 429. https://doi.org/10.3390/nu9050429.)) While that is beneficial, there are some things to consider:

• Supplementing with micronutrients is useful only if we are deficient
• The effects don’t seem linked to brain wave activity

It’s safe to say that no other known supplement can raise alpha wave levels in the brain like L-theanine.

Conclusion and Dosage Recommendations For L-Theanine

L-theanine shows a lot of promise for helping us think more clearly, feel more at ease, and sleep better. The amino acid reliably increases alpha wave levels in the brain, leading to calm that can have numerous other positive effects on our health and productivity.

Unfortunately, there isn’t a specific dosage recommendation, so we must look at what researchers have used in studies. In one of the papers we saw above, participants saw benefits from as little as 50 mg of L-theanine taken daily((Lardner, Anne L. 2013. “Neurobiological Effects of the Green Tea Constituent Theanine and Its Potential Role in the Treatment of Psychiatric and Neurodegenerative Disorders.” Nutritional Neuroscience 17 (4): 145–55. https://doi.org/10.1179/1476830513y.0000000079.)). Other studies have used doses of up to 200 mg daily. So, you might want to start on the low end, take the amino acid for a few weeks and see how it affects you.