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L-Theanine: what it is, benefits, and combinations.

L-Theanine: what it is, benefits, and combinations.

Green tea has a long-standing history as a medicinal beverage, dating as far back as 3000 B.C. in parts of China.1 The plant that green tea is made from is Camellia sinensis, a species of evergreen shrub bearing leaves that are an exceptionally rich source of chlorophyll, polyphenols, and antioxidants.

The primary polyphenols in green tea leaves belong to a class of organic compounds known as catechins, which have an exhaustive list of benefits for human health and longevity, even reducing the risk of cancer and all-cause mortality.2

However, one of the most underappreciated and overlooked nutrients found in green tea leaves is the amino acid L-theanine (n-ethylglutamic acid). In contrast to the dietarily essential and non-essential amino acids that your body uses to create proteins, L-theanine is not used for protein synthesis. Hence, L-theanine is sometimes referred to as a non-proteinogenic amino acid.

Instead of being used for protein synthesis, L-theanine has a variety of nootropic benefits throughout the brain and central nervous system. In fact, the cognitive effects of theanine are so promising that it’s being investigated as a natural/alternative therapy for mental health conditions and psychiatric disorders.3

But how does this green tea “smart drug” work? Read on as we take a deeper look at the nootropics benefits of L-theanine and how you can use this amino acid to reduce anxiety, increase focus, bolster cognitive function, and much more.

How Does L-Theanine Work? What Makes it Different than Other Amino Acids?

Whether you’re a vegetarian, vegan, carnivore, omnivore, or a caveman, a good chunk of the dietary amino acids you consume on a daily basis are used for synthesizing new proteins and subsequently repairing or building new bodily tissues.

After all, a healthy human contains roughly 65-80% of their total body mass as muscle mass.4 Muscle tissue is about 20% protein content by weight, meaning someone who weighs 160 lbs carries between 21 and 25 lbs of protein, on average. As you can imagine, that’s a lot of amino acids that your body needs to maintain and repair all that muscle tissue! 

Obviously, protein synthesis is integral for your health and wellness, but that also means that dietary amino acids have other physiological responsibilities to take care of, rendering them less potent for nootropic purposes. 

For example, L-tryptophan is an essential (i.e. proteinogenic) amino acid that also serves as a precursor for serotonin - the primary neurotransmitter involved in mood and feelings of happiness.5 However, a large proportion of the L-tryptophan you ingest (whether from food or a supplement) is going to go towards protein synthesis instead of crossing the blood-brain barrier and being used for serotonin production. This is especially true if you don’t consume much protein on a daily basis.

L-theanine, on the other hand, freely crosses the blood-brain barrier and exerts a variety of nootropic benefits. It’s well-documented that L-theanine is absorbed into the brain intact within about 30 minutes of ingestion and levels continue to increase gradually for upwards of 5 hours thereafter.6

The exact metabolic fate of L-theanine remains unclear, but it’s thought to be broken down into glutamate and ethylamide by the kidneys before being excreted in the urine.7 

What are the Benefits of L-Theanine?

In the most pithy sense, L-theanine is the nootropic for promoting alertness and relaxation, simultaneously. It almost sounds contradictory at first glance; how can you be alert and relaxed at the same time? 

The answer: Alpha brainwaves.

The alpha brainwave space is what you might think of as being in a “zen” state of mind; you’re relaxed, mindful, free from stress, and able to tune out your surroundings. If you regularly meditate, chances are you’re quite comfortable in the alpha brainwave space. 

Unfortunately, the harsh reality is that we live in a fast-paced, go-go world. Many people barely have time to stop and eat a nice home-cooked meal after a long day at work. This type of lifestyle fosters stress and anxiety, which is largely the result of being in the beta and gamma brainwave spaces.

But there’s good news…

L-theanine has also been shown to elicit selective changes in alpha brainwave activity, thereby enhancing learning, memory, and mental performance while easing anxiety and reducing stress.8  This is not to say that taking L-theanine is tantamount to meditating, rather that they work through similar neurophysiological mechanisms.

The great thing about L-theanine is that it keeps you alert while staying in that zen state of mind. As such, you won’t have to worry about feeling drowsy or tired when you take L-theanine earlier in the day.

Moreover, once L-theanine passes into the brain, it modulates the activity of several neurotransmitter systems - including GABA, dopamine, and serotonin - in a fashion that promotes calmness, attentiveness, and cognitive function.9

L-theanine has also been shown to increase levels of brain-derived neurotrophic factor (BDNF), thereby protecting neurons from degenerative processes and fortifying their integrity.10

Caffeine and L-Theanine: A Nootropic Match Made in Heaven?

For the coffee lovers out there, L-theanine is often studied alongside caffeine as the two seem to have a mutual synergy, facilitating the already stellar benefits of each.11 In other words, L-theanine is the perfect complement to your morning cup of joe by assuaging the unwanted jitters that caffeine can sometimes bring about.

Rather than the usual short burst of energy and crash that regular coffee often produces, Noocaf Focus Blend gives you hours of calm, cool, and collected focus to keep you at the top of your game throughout the day, whether you want to be more productive at the office, get more chores done at home, or psych yourself up before hitting the gym.

“Can I just drink more green tea to get the benefits of L-theanine?”

While drinking green tea may provide benefits due to the polyphenol and antioxidants, the L-theanine content of commercial green tea varieties is highly variable. In fact, one study found that the average theanine content in commercial green tea is a mere 6.56 mg/g and about 3-4 times that amount in caffeine.12

Most single-serving tea bags contain around 2-3 grams of tea, so you’re looking at 13-18.5 mg of theanine for every cup of green tea. Considering that an evidence-based dose of L-theanine starts around 100 mg taken at once, it’s quite impractical to reach that amount by drinking green tea (not to mention all the caffeine you would consume in the process).13

If you love a soothing, warm cup of joe to start the day or beat the afternoon hump, the more prudent choice is Noocaf Smart Coffee. The Focus Blend features a clinical dose of L-theanine in every cup, along with a synergistic blend of nootropics that help take the edge off and keep your mental performance at peak capacity without the jitters and crash that some coffee produces.

Interested in learning more about the science of anxiety and how you can beat it naturally? Be sure to check out for evidence-based strategies and impartial nootropic reviews that have helped thousands eliminate stress and overcome anxiety.


1. Joliffe, L. (2004). The lure of tea: history, traditions and attractions. In Food tourism around the world (pp. 133-148). Routledge.

2.  Mukhtar, H., & Ahmad, N. (2000). Tea polyphenols: prevention of cancer and optimizing health. The American journal of clinical nutrition, 71(6), 1698S-1702S.

3.  Hidese, S., Ota, M., Wakabayashi, C., Noda, T., Ozawa, H., Okubo, T., & Kunugi, H. (2017). Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta neuropsychiatrica, 29(2), 72-79.

4.  Holloszy, J. O., & Nair, K. S. (1995). Muscle protein turnover: methodological issues and the effect of aging. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 50(Special_Issue), 107-112.

5.  Owens, M. J., & Nemeroff, C. B. (1994). Role of serotonin in the pathophysiology of depression: focus on the serotonin transporter. Clinical chemistry, 40(2), 288-295.

6.  Juneja, L. R., Chu, D. C., Okubo, T., Nagato, Y., & Yokogoshi, H. (1999). L-theanine—a unique amino acid of green tea and its relaxation effect in humansTrends in Food Science & Technology10(6), 199-204.

7.  Tsuge, H., Sano, S., Hayakawa, T., Kakuda, T., & Unno, T. (2003). Theanine, γ-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase. Biochimica et Biophysica Acta (BBA)-General Subjects, 1620(1-3), 47-53.

8.  Mason, R. (2001). 200 mg of Zen: L-theanine boosts alpha waves, promotes alert relaxation. Alternative & Complementary Therapies, 7(2), 91-95.

9.  Yamada, T., Terashima, T., Okubo, T., Juneja, L. R., & Yokogoshi, H. (2005). Effects of theanine, r-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission. Nutritional neuroscience, 8(4), 219-226.

10.  Wakabayashi, C., Numakawa, T., Ninomiya, M., Chiba, S., & Kunugi, H. (2012). Behavioral and molecular evidence for psychotropic effects in L-theanine. Psychopharmacology, 219(4), 1099-1109.

11.  Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., & Scholey, A. B. (2008). The effects of L-theanine, caffeine and their combination on cognition and moodBiological psychology77(2), 113-122.

12.  Boros, K., Jedlinszki, N., & Csupor, D. (2016). Theanine and caffeine content of infusions prepared from commercial tea samples. Pharmacognosy magazine, 12(45), 75.

13.  Lardner, A. L. (2014). Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders. Nutritional neuroscience, 17(4), 145-155.

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