L-Theanine Dosage for Anxiety Relief and Enhanced Cognition


L-theanine is a non-dietary amino acid first discovered as one of the components of green tea leaves.

It is structurally similar to the amino acid glutamine, GABA, and glutamate. Although unlike GABA supplements, L-theanine readily crosses the blood-brain barrier and evokes a variety of nootropic effects one of them being relaxation which is why you may be considering supplementing L-Theanine for anxiety.[i]

The properties of L-theanine can be summed up as “alert relaxation” because it acts as a relaxing agent without sedating you, I know that may sound like a bit of an oxymoron,  BUT, L-theanine is superb for both reducing anxiety and enhancing cognition!

It may also help with sleep although it is not likely to induce sleep like other nootropics such as 5-HTP.

The relaxing and cognitive promoting properties of L-theanine (paired with the lack of sedation) make L-Theanine ideal for attenuating the high (and possible anxiety) many stimulants can induce.

For example, a combination of L-Theanine with caffeine has been found to be synergistic in supporting cognition and attention.[ii]

Pro Hacks:

  • L-theanine will help you maximize the effects of caffeine/coffee and reduce anxiety.
  • As little as 200mg of L-theanine can increase cognition and improve well-being.
  • L-theanine relaxes you without sedating you, meaning you can remain productive and calm throughout the day.
  • Try stacking L-theanine with other nootropics, such as 5-HTP or GABA, for heightened effects.
  • L-Theanine is just one of many over the counter supplements that can help your anxiety, to find out about others get our free Anxiety Supplement Guide by clicking the button below!

How L-Theanine Works

L-theanine hasn’t been shown to significantly alter levels of any primary neurotransmitters (e.g. dopamine, serotonin, adrenaline, GABA, etc).

The keyword there being significant, as minor changes in GABA, noradrenaline and serotonin levels do occur after taking L-theanine.4

While many nootropics exert their benefits by altering levels of the aforementioned neurotransmitters, it appears that most of L-theanine’s effects come from increased alpha waves in the brain.[iii]

Alpha waves are one of the two most frequent types of waves produced in the brain when we are awake, with the other being beta waves.

People who are in a resting state or coming down from a busy set of activities are often in the alpha brain wave space

When we are highly involved, active, or engaged in difficult mental activities your brain waves are functioning at the beta level.

It’s important to note that L-theanine administration significantly increases alpha waves in the brain without decreasing beta waves, thus it induces relaxation without sedation.

Moreover, L-theanine administration has been shown to reduce corticosterone levels in the brain, which is a positive for memory retention.[iv]

Corticosterone is a major stress hormone that typically increases when memories of fear are recalled. Thus, by taking L-theanine, the stress and anxiety induced by fearful memory recognition is generally lessened.

On a final note, research suggests that L-theanine promotes nitric oxide (NO) production in cells that line the inside of blood and lymphatic vessels.[v]

This is particularly important in that these cells are crucial for protecting against vascular diseases (such as hypertension and coronary artery disease), and decreased NO production is a sign of dysfunction.

Therefore, L-theanine is suggested to be beneficial for supporting proper blood and lymph flow throughout the body.

Benefits of L-Theanine Supplementation

Thanks to its high bioavailability and simple uptake into the brain, supplementation with L-theanine has been shown to be effective for inducing a variety of psychologically beneficial properties, including stress support (relaxation) and promotion of cognitive function.1, 3

Research also suggests that L-theanine administration significantly increases alpha waves in the brain, without decreasing beta waves.[vi]

Thus, when its ingested, users tend to feel more calm but yet attentive.

Clinical research suggests the benefits of L-Theanine  include:

Supports proper anxiety management and relaxation without being sedated[1, 3]

Promotes cognitive function[7]

Attenuates sensitivity to stimulants[2]

Reduces stress-induced memory recognition[4]

Supports healthy vascular function5,[8]

Taking L-Theanine For Anxiety

While many nootropics fight anxiety by increasing serotonin production, L-theanine doesn’t appear to follow that path.

In fact, significantly large doses of it actually reduce serotonin levels (despite increased levels of tryptophan in the brain).[ix]

As noted earlier, L-theanine does however increase alpha wave production in the brain which is associated with feelings of restfulness and peace.

The main difference between L-theanine and most other nootropics is that the increase in alpha waves is independent of decrease in beta waves.

In turn, this makes it a great over-the-counter anxiety reliever without making users feel drowsy/sedated.

In some regards, it is also actually advantageous that L-theanine doesn’t increase serotonin levels as that may also induce drowsiness and impede productivity during the day.

Another benefit of this is that L-theanine pairs well with nootropics that do fight anxiety by increasing serotonin (and other neurotransmitters) since they don’t actively compete for the same receptors.

In fact, one study noted that 400mg of L-theanine per day, in conjunction with antipsychotic treatment, significantly improved anxiety symptoms in patients with chronic schizophrenia, when compared to placebo.[x]

On the same token, another study demonstrated that 250mg of L-theanine per day was safe and had multiple beneficial effects on depressive symptoms, anxiety, sleep disturbance and cognitive impairments in patients with major depressive disorder.[xi]

As an over-the-counter medication, L-theanine’s anxiety-fighting properties are well-supported by research.

However, do note that L-theanine should not be used in conjunction with selective-serotonin reuptake inhibitors (SSRIs) without prior approval from a licensed physician.

There doesn’t appear to be any drug interactions between L-theanine and SSRIs, but nevertheless it behooves users to err on the side of caution.

L-Theanine Dosing Recommendations

Research suggests that 100mg to 200mg taken orally is effective for reducing anxiety and supporting cognitive function. Due to its relatively short half-life, L-theanine can be taken up to four times daily, spread roughly three to four apart per dose.

Note that some stimulants may actually increase anxiety when taken in large quantities.

Thus, L-theanine also serves as a great combo supplement when taking stimulants (particularly caffeine). Generally, every 200mg of caffeine pairs well with 100mg of L-theanine.

It is also impractical to consume nominal amounts of L-theanine by drinking green tea, as the amount needed would likely cause gastrointestinal issues and be inefficient compared to taking supplemental L-theanine.

L-Theanine Side Effects

L-theanine is arguably one of the safest nootropics available in terms of having near nonexistent side effects. Unless consuming exorbitant amounts of L-theanine, it should be very well-tolerated by most all individuals.

In fact, L-theanine is one of the few over-the-counter medications the Food and Drug Administration (FDA) has given the GRAS (Generally Recognized As Safe) accolade.


When comparing the anxiety-reducing effects of L-theanine to other nootropics, we tend to recommend L-theanine for those who want to stay alert and on task while feeling relaxed.

Since many nootropics significantly alter neurotransmitter levels, such as serotonin, they also have an inherent sedative quality that makes them imprudent for daytime use.

Thankfully, L-theanine has different mechanisms for reducing anxiety that bypass pathways that induce drowsiness.

Also, L-theanine makes a great addition to other nootropics and stimulants, as it acts to bolster their effects.

With a remarkable safety profile, high affordability, and bounty of literature supporting its benefits, L-theanine makes for an exceptional over-the-counter medication, especially for fighting anxiety.

Frequently Asked Questions:

Q: Can I become dependent on L-theanine if I supplement with it continuously?

A: No, L-Theanine is non-habit forming and can be used regularly for relaxation and cognitive support.

Q: Will I become drowsy if I take L-theanine during the daytime?

A: L-theanine doesn’t have much potency in terms of sedation so it is unlikely that a nominal dose will make you drowsy.

Q: Can I take L-theanine with SSRI medication?

A: As always, we suggest you consult with a licensed physician before you combine L-theanine with any prescribed medications (including SSRIs).

Q: Does it matter if I take L-theanine with food or on an empty stomach?

A: No, L-theanine is well absorbed into the brain with or without food.


[1] 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 humans. Trends in Food Science & Technology10(6), 199-204.
[2] 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 mood. Biological psychology77(2), 113-122.
[3] Song, C. H., Jung, J. H., Oh, J. S., & Kim, K. S. (2003). Effects of theanine on the release of brain alpha wave in adult males. Korean Journal of Nutrition36(9), 918-923.
[4] Tian, X., Sun, L., Gou, L., Ling, X., Feng, Y., Wang, L., … & Liu, Y. (2013). Protective effect of l-theanine on chronic restraint stress-induced cognitive impairments in mice. Brain research1503, 24-32.
[5] Siamwala, J. H., Dias, P. M., Majumder, S., Joshi, M. K., Sinkar, V. P., Banerjee, G., & Chatterjee, S. (2013). L-Theanine promotes nitric oxide production in endothelial cells through eNOS phosphorylation. The Journal of nutritional biochemistry24(3), 595-605.
[6] Song, C. H., Jung, J. H., Oh, J. S., & Kim, K. S. (2003). Effects of theanine on the release of brain alpha wave in adult males. Korean Journal of Nutrition36(9), 918-923.
[7] Kim, T. I., Lee, Y. K., Park, S. G., Choi, I. S., Ban, J. O., Park, H. K., … & Hong, J. T. (2009). l-Theanine, an amino acid in green tea, attenuates β-amyloid-induced cognitive dysfunction and neurotoxicity: reduction in oxidative damage and inactivation of ERK/p38 kinase and NF-κB pathways. Free Radical Biology and Medicine47(11), 1601-1610.
[8] Yokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., & Takeuchi, N. (1995). Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Bioscience, biotechnology, and biochemistry59(4), 615-618.
[9] Yokogoshi, H., Mochizuki, M., & Saitoh, K. (1998). Theanine-induced reduction of brain serotonin concentration in rats. Bioscience, biotechnology, and biochemistry62(4), 816-817.
[10] Ritsner, M. S., Miodownik, C., Ratner, Y., Shleifer, T., Mar, M., Pintov, L., & Lerner, V. (2010). L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study. The Journal of clinical psychiatry72(1), 34-42.
[11] Akhondzadeh, S., Gerbarg, P. L., & Brown, R. P. (2013). Nutrients for prevention and treatment of mental health disorders. Psychiatric Clinics of North America36(1), 25-36.


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