L-Theanine (γ-glutamylethylamide), is a unique amino acid present almost exclusively in the tea plant. In recent years, several potential health benefits of drinking tea (derived from the Camellia sinensis plant species) have come to light through systematic study of the effects of its constituent compounds.
It was first isolated in 1949 by Japanese scientists who found that it gives green tea its well-known potency as a mood lifter and concentration enhancer. It appears to alter levels of various neurotransmitters, producing a calming effect that helps counter the stimulating action of the caffeine in tea.
Now, L-Theanine is recognized as a nootropic used for cognitive enhancement. Most reports share that it increases dopamine and improves mood, naturally boosts focus, memory and brain health, and aids in reducing stress & anxiety. Researchers claim that L-Theanine also boosts alpha waves, electrical brain signals that accompany intense focus, deep relaxation, and creativity.
Using electroencephalographic (EEG) recordings in humans, scientists reported that activity within the alpha frequency band (8–14 Hz) increased in reaction to L-theanine ingestion when measured during a state of rest.
A combination of L-Theanine with Caffeine (200mg each) is noted to be synergistic in promoting cognition and attention. According to examine.com, here is what is being said for these specific outcomes:
- Relaxation: A notable increase in relaxation (usually without sedation) appears to occur, as assessed by neural measurements (such as alpha-waves) or self-report surveys. Occurs within 30 minutes to an hour.
- Quality of Sleep: Sleep quality has been noted to improve in persons with hyperactivity during sleep (such as ADHD). Sleep duration and latency do not appear to be affected.
- Anxiety: Possible anxiety reducing effects, although anticipatory anxiety appears to be unaffected.
- Schizophrenia: Activation and anxiety symptoms of schizophrenia appear to be reduced with high dose (400mg) Theanine
Note that most of the above findings have been with animal research. In fact, most all quantitative nootropic studies are conducted with animals. Human studies are more rare but are starting to pop up.
For example, according to Berkeley University, some preliminary human studies, using doses of L-theanine about 10 to 20 times higher than that in a cup of tea, have suggested possible benefits, such as the following:
- In a Japanese study in the Journal of Physiological Anthropology, college students who took L-theanine experienced less anxiety and had smaller increases in blood pressure when under psychological or physical stress than when they took a placebo.
- Similarly, another Japanese study in Pharmacology, Biochemistry, and Behavior found that graduate students who took L-theanine experienced less anxiety when they were assigned stressful work in a pharmacy, compared to a placebo.
- In a Canadian study in Alternative Medicine Review, L-theanine improved some aspects of sleep quality in boys with attention-deficit hyperactivity disorder (ADHD).
- In a preliminary Israeli study in the Journal of Clinical Psychiatry, L-theanine helped relieve anxiety symptoms and augment antipsychotic treatment in patients (ages 19 to 55) with schizophrenia.
Most of the studies have been small and short-term. Berkeley also notes that many have had methodological weaknesses, and the findings have been inconsistent.
Even though scientists report inconsistent findings, there are many people who enjoy taking L-theanine. People are commonly using theanine for treating anxiety and high blood pressure, for preventing Alzheimer’s disease, and for making cancer drugs more effective.
In fact, some people are even treating their pets with it. Here’s what this user reports:
“L-Theanine is used for pets in case of excessive barking, anxiety, fear, bad listening etc. When I buy L-Theanine for dogs in Holland it will cost me about 40 dollars a month ! I saved a lot of money buying Doctor's Best L-Theanine at iHerb. After 7 months of using I can get my dog's attention when she is barking, she listens better and has no fear of thunder, lightning and even fireworks anymore. She also has much more self-confidence. That's a result of training but without L-Theanine it was not possible to train. I'm very happy with the results and surprised it's so effective. Before using I did not believe it could work but I was wrong!!”
Here is what one user shared of her own experience,
“LOVE, LOVE THESE LITTLE WHITE CAPSULES! They really help me stay calm and focus during stressful situations at work. I take one every day, but on really stressful days I take 3. I gave a few to my sister who is currently under a lot of stress seeking employment. She was so impressed, she went out and bought a bottle at a local health food store for 3 times the price i paid on iHerb.”
Another user shares…
“I started with 150mg at bedtime, and found it lowers my morning fasting blood sugar! I did not expect this, but discovered it while I was testing frequently. This may be due to the comments I see on the net that theanine can lower cortisol…which is considered a factor in some “dawn phenomenon” patients with insulin resistance/type II diabetes. I don't know if this is really the explanation, but it certainly lowered my morning fasting glucose readings by 30pts or more!
During the course of this bottle which is a 90 ct size, our home has had a major stressor, and grief generator, and I have been very upset during this time. So last night I took 300mg instead of the usual 150mg. I slept more soundly, and awakened with a less “heavy heart”…which is what I call my anxiety grief reaction to the acute/temporary stress here.
If I feel the return of this anxiety today, I'll take 150mg in the daytime, and another 300mg at bedtime. I am very pleased with this product for myself. But I do think people may vary in their responses. And I think perhaps a higher dose may work for those that are not satisfied with 150mg a day.”