L-theanine is a fat-soluble amino acid derived from green tea; in fact, it is the compound that gives green tea its unique taste. Renowned for its calming effects, research suggests that L-theanine works by enhancing alpha-wave activity, the brain waves associated with an awake, relaxed state.1-2
Theanine also plays a role in the production of gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter that stops your brain from sending messages that rile you up. Instead, it promotes messages of calm and relaxation.
Research also indicates that theanine offers neuroprotection and cognitive enhancement, as well as its anti-anxiety and anti-stress effects.
Conditions Supported by Acupuncture
- Brain health
What Does the Research Say?
Theanine is well-studied when it comes to its effects on reducing anxiety. For example, in one study, eight college-aged female were equally divided into low anxiety and high anxiety groups.3 Over a period of two months, they were given either water, water with 50 mg of theanine or water with 200 mg of theanine.
Within 40 minutes, researchers detected alpha brain waves in those volunteers who drank the water containing L-theanine. In fact, the brain wave activity was significantly greater and more intense in the anxious group, indicating that theanine has the highest efficacy among those who need it the most.
They concluded, “These results indicate the possibility for L-theanine to be applied to foods and beverages as a new type of functional food ingredient for its relaxation effect.”
In a separate study published in October 2012, researchers found that theanine reduced anxiety as well as blood pressure in high stress-response adults.4 Fourteen subjects underwent three separate trials in which they received L-theanine plus placebo, caffeine plus placebo or placebo alone. The researchers monitored blood pressure in the subjects after completing a mental task. The subjects completed the Profile of Mood States to assess for anxiety after completing the mental task.
The researchers found that L-theanine significantly inhibited the blood-pressure increases in the high-response group after the mental task, which consisted of subjects whose blood pressure increased more than average by a performance of a mental task after placebo intake. The investigators showed that caffeine tended to have a similar but smaller inhibition of the blood-pressure increases caused by the mental tasks. In addition, the Profile of Mood States questionnaire after the mental tasks revealed that L-theanine reduced the Tension-Anxiety scores compared to placebo.
The study authors stated, “The findings above denote that L-theanine not only reduces anxiety, but also attenuates the blood-pressure increase in high-stress-response adults.”
Theanine has even been shown to work as well as the commonly prescribed anti-anxiety drug Xanax(R). In a double-blind, placebo-controlled study published in 2004,5 researchers had 16 volunteers take each of the following treatments at three separate times:
- 1 mg of Xanax (alprazolam)
- 200 mg of theanine
After each treatment, the participants were given a series of subjective, self-reports related to anxiety. Additionally, the tests were given under both relaxed and induced-anxiety states.
Researchers found that the theanine induced relaxation at the initial measurement. Neither Xanax nor the placebo resulted in this effect. Additionally, during the anxiety-induced phase, neither Xanax nor theanine had any significant effect. That means that not only does theanine work as well as the medication during acute stress (which is to say some, but not significantly), it outperforms the medication when it comes to every-day anxiety.
Theanine has been shown to have overall brain protective properties.6 But where it really shines in focus and attention.
In a study conducted by researchers affiliated with the U.S. Air Force, the investigators wanted to know if theanine created changes in the area of the brain, which would in turn create changes in anticipatory alpha activity.7 This is critical, as this can affect your ability to react to stimulus during tasks that involved discriminatory focus and attention.
Volunteers were hooked up to scalp electrodes and their EEGs were recorded while they underwent a standard cuing task that required focused attention. As noted in previous studies, there was a significant increase in alpha brain wave activity when the participants were doing the task.
Interestingly, after taking theanine then performing the task, researchers noted a substantial decrease in overall alpha waves, yet a significant increase in the alpha activity related to the attention-requiring tasks.
Researchers concluded, “This increase of attention-related anticipatory alpha over the right parieto-occipital scalp suggests that theanine may have a specific effect on the brain’s attention circuitry. We conclude that theanine has clear psychoactive properties, and that it represents a potentially interesting, naturally occurring compound for further study, as it relates to the brain’s attentional system.”
When it comes to sleep, theanine seems to work particularly well if your insomnia is due, in part, to stress and nervous tension.
In a study published in 2011, researchers tested the effects of theanine on sleep quality in boys with ADHD.8 In this randomized, double-blind, placebo-controlled study, researchers divided 98 boys between the ages of 8 and 12 with known ADHD into one of two groups. The first received 200 mg of theanine twice a day (400 mg daily), while the second group received a placebo.
At the end of six weeks, researchers found that the boys who took the theanine had significantly better sleep (both duration and efficiency) than those who took the placebo. They also enjoyed more consistent sleep and woke up less often during the night than those who received the placebo.
Researchers concluded, “This study demonstrates that 400 mg daily of L-theanine is safe and effective in improving some aspects of sleep quality in boys diagnosed with ADHD. Since sleep problems are a common co-morbidity associated with ADHD, and because disturbed sleep may be linked etiologically to this disorder, L-theanine may represent a safe and important adjunctive therapy in childhood ADHD.”
Given theanine’s ability to reduce anxiety, it’s no surprise that it has also been shown to reduce stress.
This was seen in a study published in October 2013.9 Subjects included 20 fifth-year college students enrolled in a pharmacy course. The students received a placebo or 200 mg theanine twice daily after breakfast and lunch beginning one week prior to the pharmacy practice and continued for 10 days in the practice period.
The subjects completed the state-trait anxiety inventory test prior to the pharmacy practice to assess anxiety. The researchers also measured salivary alpha-amylase activity as a marker of sympathetic nervous system activity.
The investigators determined that morning salivary alpha-amylase was higher in the placebo group compared to the theanine group. Additionally, the researchers found that subjective stress was lower in the theanine group compared to the placebo group. The investigators also found that the students with higher pre-practice salivary alpha-amylase correlated with significantly higher trait anxiety and correlated with shorter sleeping time.
The study authors concluded, “Stressful condition increased the level of salivary alpha-amylase that was essentially affected by individual trait anxiety. The low levels of pre-practice salivary alpha-amylase and subjective stress in the theanine-group suggest that theanine intake suppressed initial stress response of students assigned for a long-term commitment of pharmacy practice.”
How to Use Theanine
If you are interested in using theanine, the commonly recommended dosage is 400 mg a day.
- Kimura K, et al. Biol Psychol. 2007 Jan;74(1):39-45.
- Nobre AC, et al. Asia Pac J Clin Nutr. 2008;17 Suppl 1:167-8.
- Kobayashi K, et al. Nippon NOgei Kagakukaishi. 1998;72(2):153-7.
- Yoto A, et al. J Physiol Anthropol. 2012 Oct 29;31(1):28. [Epub ahead of print.]
- Lu K, et al. Hum Psychopharmacol. 2004 Oct;19(7):457-65.
- Nathan PJ, et al. J Herb PHarmacother. 2006;6(2):21-30.
- Gomez-Ramirez M, et al. Clin Neuropharmacol. 2007 Jan-Feb;30(1):25-38.
- Lyon MR, et al. Altern Med Rev. 2011 Dec;16(4):348-54.
- Unno K, et al. Pharmacol Biochem Behav. 2013;111:128-35.