What is L-theanine? And why you’ll want to know
6 mins read

What is L-theanine? And why you’ll want to know


It’s an ongoing battle, and if you’re short on weaponry it’ll be a rough go. Living with emotional and mental illness demands consideration of as many relief options as possible. What is L-theanine? Here’s why you’ll want to know.

Though more confirming research is needed, L-theanine shows promise for cognitive and mental health issues, boosting attention and working memory, relieving depression…

We all know the big players: therapy, meds, exercise, healthy diet, and adequate sleep.

But there are other weapons we can use to secure relief for our emotional or mental illness. For instance, supplements – like L-theanine.

What is L-theanine?

Reported benefits of L-theanine

Camellia sinensis

L-theanine (aka theanine) is an amino acid typically derived from the camellia sinensis shrub, its leaves used to produce tea. Another source is bay bolete mushrooms.

A unique characteristic of L-theanine is its ability to cross the blood-brain barrier. You may know that the blood-brain barrier (BBB) is a tightly locked layer of cells that defend the brain from harmful substances and keep essentials inside.

By the way, there are a significant number of therapeutic applications in the works that target the BBB. Included are treatments for neurodegenerative diseases and improving the understanding of mental health disorders,

Reported benefits of L-theanine

L-theanine supplements are typically used to help folks relax, destress, and sleep better.

But that’s not all. Though more confirming research is needed, L-theanine shows promise for cognitive and mental health issues, boosting attention and working memory, relieving depression, improving symptoms caused by attention-deficit/hyperactivity disorder (ADHD), and schizophrenia and Tourette syndrome treatment.

That’s quite a list. It’s important to keep in mind that L-theanine’s positive impact on specific disorders isn’t because it addresses root causes. Rather, it reduces symptom severity.

It’s also believed that L-Theanine may lend an hand to our immune response to infection.

And how ‘bout this? Scientists have suggested caffeine may bolster L-theanine’s impact on cognition and working memory.

Finally, 200 mg of L-theanine is approximately the amount found in eight cups of tea.

FDA classification

The United States Food and Drug Administration (FDA) classifies L-theanine as “generally recognized as safe” (GRAS).

Because of that, it’s exempted from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive tolerance requirements.

L-theanine and GABA

It appears as though L-theanine primarily impacts the most abundant inhibitory neurotransmitter in the brain, gamma-amino butyric acid (GABA).

L-theanine and GABA

Hyperrealistic details of GABA receptor communication under a microscope

Since GABA is located all over the brain, its work is said to be brain all-inclusive. It’s believed GABA has the ability to unlock and actually bring to life anxiety-inhibiting receptors on nerve cells, and it also has sleep-inducing characteristics.

If’s no coincidence, then, that the benzodiazepines’ – alprazolam (Xanax), diazepam (Valium), clonazepam (Klonopin), temazepam (Restoril), etc. – mode of action targets the GABAA receptor.

Dosing

I almost skipped discussing dosing because it varies by application and I don’t want to come off like I’m making recommendations.

That said, it’s interesting; so here’s some information from Drugs.com. For the sake of emphasis, I’m not making recommendations and I encourage you to chat with your physician if you’re thinking about using L-theanine.

Important: they begin by stating, “Robust, unequivocal data are currently unavailable to support dosing for any clinical use.”

Cardiovascular: Supplementation with 50 mg or 200 mg of L-theanine has been used in healthy adults to attenuate acute caffeine-induced cerebral hemodynamics or behaviors and stress-induced increases in heart rate or blood pressure, respectively.

Schizophrenia: Adjunctive L-theanine 250 mg/day or 400 mg/day for 8 weeks (ie, in addition to current antipsychotic medication) has been studied for use in improving Positive and Negative Syndrome Scale (PANSS) positive and general psychopathology scores in patients with schizophrenia.

Sleep disorders: Adjunctive use of L-theanine 250 mg/day or 450 mg/day (225 mg twice daily) for 8 weeks (ie, in addition to current antipsychotic medication) has been studied for improvement of some sleep measures in patients with major depressive disorder, schizophrenia, or generalized anxiety disorder (GAD).

Potential problems

According to my research, there are no well established contraindications or interaction issues pertaining to L-theanine use.

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Again, check with your doc if you have questions or concerns.

Adverse reactions

Few adverse reactions to L-theanine use have been reported. However, recorded in human pharmacokinetic studies evaluating tea extracts are headache, dizziness, and GI symptoms.

High-density lipoprotein cholesterol (HDL-C) decreased significantly in adults with major depressive disorder administered adjunctive L-theanine.

Give it a go?

Yes, living with emotional and mental illness is an ongoing battle. And devoting time and effort to finding every suitable weapon is crucial.

Lord knows there are tons of supplements out there – many not worthy of consideration. However, L-theanine isn’t one of them. So if you’re wondering if it’s a fit, study up, check with your doc, and give  it a go.


Those Chipur emotional and mental illness info and inspiration articles: Peruse the titles.

Thanks to Verywell Health for the resource material in “L-Theanine: Everything You Need To Know,” written by Regina C. Windsor, MPH, RDN. Tip of the hat to drugs.com as well.

Bill White is not a physician and is providing the contents of this article for information purposes, not to serve as a recommendation. Contact your physician with questions and for advice.

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