The Benefits of L-Theanine: Natural Anxiety & Sleep Relief

Do you enjoy a cup of tea in the morning? Drinking black or green tea is more than a great-tasting way to wake up—it can also benefit your physical and mental well-being.  

Tea, also known as Camellia sinensis, contains L-theanine, which possesses numerous health benefits. This amino acid contains multiple anti-cancer and neuroprotective properties and the potential to aid sleep, reduce anxiety, and mitigate degenerative illness.

Let’s explore L-theanine’s benefits for the mind and body.

Who Discovered L-Theanine?

In 1949, scientists in Japan at the Ministry of Agriculture were studying the chemical properties of tea. As part of their research, they discovered the main amino acid in tea leaves: L-theanine.

L-theanine’s content can double if the tea is shade-grown, as Gyokuro green teas are in Japan. Before L-theanine was discovered, farm shading practices had already been boosting tea’s flavor-enhancing qualities.

Green tea has the most L-theanine content by weight, but white tea, oolong, and black teas all contain significant quantities as well. The highest-grade, shade-grown teas can contain amino acid levels of over 10%.

What Does L-Theanine Taste Like?

L-theanine has a unique flavor similar to umami. Umami is a savory, rich flavor in meat broth, mushrooms, tomatoes, parmesan cheese, and soy sauce.

It is one of the five basic tastes, along with sweet, salty, sour, and bitter. Umami was named in 1908 by a Japanese chemist, Kikunae Ikeda, who identified glutamate as the source of umami flavor.

L-theanine is chemically similar to glutamate and activates the umami receptors on the tongue.

What Does the “L” in L-Theanine Stand for?

Theanine comes in two forms which mirror each other: L-theanine and D-theanine. Scientifically called L-gamma-glutamylethylamide, L-theanine has been extensively studied. This is because, after consumption, L-theanine is readily available in the body for study and possesses more known health benefits, boosting its research focus.

On the other hand, the “d” in D-theanine stands for dextro. Since D-theanine doesn’t affect the body in the same manner as L-theanine, more study is needed to fully understand its properties and effects.

What Are Sources of L-Theanine Other Than Tea?

Although sources of L-theanine are limited, there are other, lesser-known sources of this beneficial amino acid, including:

• Edible Mushrooms: Boletus badius contains small amounts of L-theanine. While not as abundant as in tea, this mushroom can be a dietary source if consumed regularly.
• Chocolate: Although the amount is minimal, some types of dark chocolate, particularly those with higher cacao content, contain trace amounts of L-theanine that lower blood pressure and improve attention.

How L-Theanine Works: Biochemistry Mechanisms

Since L-theanine easily crosses the blood-brain barrier, it can quickly affect your brain. One effect is drowsiness, which aids sleep.

Because L-theanine is chemically similar to glutamate, it also affects the body through glutamate receptors. In addition to being a flavor enhancer, glutamate is a neurotransmitter that regulates excitatory pathways in your nervous system. L-theanine affects glutamate re-uptake and receptors, reducing their firing rates.

In addition to affecting GABA and glutamate pathways, the body metabolizes L-theanine into glutamate, which then can be processed into GABA, directly influencing their pathways.

L-Theanine and GABA

L-theanine boosts GABA, which is known to produce a calming effect. It plays a major role in controlling nerve cell hyperactivity associated with anxiety, stress and fear.

GABA is a neurotransmitter that helps your body relax. It’s an important part of the chemical process that stills your body while you are experiencing active dreams.

Like L-theanine, GABA can also be found in tea leaves of Camellia sinensis plants.

Therapeutic Uses for L-Theanine

L-theanine is used as a natural supplement for anxiety, weight loss, and sleep, and as a potential preventative for Alzheimer’s and Parkinson’s. Let’s unpack these.

L-Theanine for Anxiety: The results are mixed, but there have been studies that suggest L-theanine helps provide mild to moderate reduction in anxiety among both healthy people and people with anxiety-related mental illnesses.

L-Theanine for Weight Loss: L-theanine possesses two potential ways it can help weight loss—it has been shown to suppress fat accumulation in the body and when consumed in tea form and help you feel satiated, making you less likely to over-eat.

L-Theanine as a Sleep Aid: Consumption of L-theanine has been found to decrease attention and response time and makes you more relaxed but it isn’t a sedative.

L-theanine helps you fall asleep, reduces sleep disturbances, and increases the quality of deep NREM (non-REM) sleep.

Sleep researchers are finding that NREM sleep is more important than previously understood. It has been found crucial for restoring energy levels, immune function, and memory regulation.

L-Theanine as a Neuroprotector: L-theanine is just one of the components in tea that curbs damage from neurodegenerative diseases like Alzheimer’s Disease. While studies suggest the polyphenol in tea—known as epigallocatechin-3-gallate (EGCG)—can inhibit the formation of plaques that lead to Alzheimer’s, L-theanine offers more general neuro-protective properties that reduce the effects of oxidative damage associated with the disease.

Taking L-Theanine Supplements vs. Drinking Tea

The main perk of drinking tea versus taking supplements is that tea contains other healthful components: polyphenols with powerful antioxidant properties.

The benefit of taking supplements is that it’s easier to reach a therapeutic dose. A 200 mL serving of tea typically contains 20mg of L-theanine. A therapeutic dose of L-theanine can vary but often contains about 200mg. 

On the other hand, if you were to drink tea to reach a 200mg dose, that would translate to 10 cups! At that point, the caffeine content would offset the relaxing effect of L-theanine and disrupt your sleep.

Add in the fact that the L-theanine content of teas can vary based on processing and brewing techniques, then you wouldn’t know how much L-theanine you’re consuming.

However, taken as a supplement, you can experience all the relaxing effects of L-theanine, minus the side effects. You can increase your L-theanine dosage without increasing your caffeine intake and you’ll know exactly how much you’re taking. Enjoy the relaxation and restorative sleep!