The Benefits of L-Theanine in Tea

Guest post by Gerard Paul

Admittedly, I’m primarily a coffee drinker. But apart from water, tea is the most common beverage enjoyed by people around the world.

Tea is known for being high in flavonoids like flavonols and catechins. However, tea also is one of the very few natural sources of L-theanine – a non-essential amino acid.

All varieties and types of regular tea contain L-Theanine, including black and green tea. And theanine is an interesting amino acid – although we’ve known about tea for centuries, we’re just now isolating some of its effects of the theanine contained inside.

What is L-Theanine?

L-theanine is a water-soluble amino acid found in tea leaves and a few other plants. 

According to one roundup study, L-Theanine has been utilized as a relaxing product throughout history. Research suggests that L-theanine increases the levels of dopamine, serotonin, and GABA levels in the brain. 

The chemical make-up of theanine is quite comparable to the amino acid glutamate. Some of the effects of L-theanine come about because it blocks some glutamate receptors in the brain, thereby upregulating the neurotransmitter GABA. GABA in an inhibitory transmitter, and your glutamate and GABA balance interplays with some conditions – and even moods.

The Major Sources of L-Theanine

Natural Theanine can be found in some mushrooms and plants, primarily the Camellia family – and most often found in the Camellia sinensis plant (the tea plant).

Other sources of l-theanine also include Camellia sasanquaCamellia japonica, and the mushroom Imleria badia. (And some closely related species as well).

Camellia sasanqua or sasanqua camellia is an evergreen shrub that grows to around 16 feet tall and is native to Japan and China. Camelia japonica (or “Japanese camellia”) has thousands of cultivars and grows in Alabama – it’s the State flower – the UK, and Asia. Imleria badia, (the “bay bolete”) is an edible mushroom that grows up to 6 inches in diameter found in Europe and North America. 

While all species of Camellia can be used to make tea, the most important is Camellia sinensis. Camellia sinensis is an evergreen shrub or small tree whose buds and leaves are utilized to create all types of tea – black to green to white and everything in between.

Black teas and green tea include:

  • Black tea – one cup (200 ml) contains 24.2 mg of l-theanine
  • Green tea – one cup (200 ml) contains around 7.9 mg of l-theanine 

According to SF Gate, dried black tea leaves contain approximately 25 to 60 milligrams of L-theanine per 7 ounces (200 milliliters). Decaffeinated black tea has a little less – 0.7 percent to 1.8 percent of dry weight as opposed to regular black tea. Green tea contains 0.8 percent to 2.7 percent of its dry weight that consists of amino acids. 

As for herbal teas? They are generally not considered a good source of L-theanine. 

Theanine, Dopamine, Serotonin, and GABA

As mentioned, theanine is known to increase GABA in the brain. GABA, again, is an inhibitory neurotransmitter – it produces a calming effect in the brain.

It also increases the release of dopamine and serotonin while decreasing norepinephrine. Dopamine and serotonin are closely linked to memory and learning; theanine might have some positive effects on learning. 

Interestingly, it also decreases artificially elevated serotonin levels from substances like caffeine. As most natural theanine consumption is in tea with, well, caffeine, this might contribute to some of theanine’s interesting interactions with caffeine – but more on that later!

Health Effects of Theanine

Theanine is most famous for its relaxing effects. 

However, L-theanine has many other health benefits (although many are controversial, especially in Europe). According to Medical News Today, studies show that theanine may offer a wide variety of health benefits beyond its calming claim to fame – including help for insomnia and better mental focus. 

Relieves Stress & Anxiety

Hot tea already makes you feel better and more relaxed – consider the popularity of all sorts of tea, including those from plants without known (or proven) health effects. As you know, a lot of research indicates that tea is especially beneficial for people who have anxiety. It also smoothly provides those benefits, without drowsiness or substantially lowered heart rate,

There are also claims that L-theanine may help with specific disorders such as schizophrenia

Increase Focus & Attention Span

Recent studies show that L-theanine may help improve your attention span and your focus when combined with caffeine. In fact, by itself, theanine can increase your concentration by helping you to relax your mind and even clear lingering brain fog. 

What is more, some people anecdotally claim that it puts them in a “state of meditation”. 

As for me? I can comment on this point, too – it does feel like around 20-30 minutes after having theanine in tea, I feel “something” different than how I do with coffee. It’s smoother attention in my mind – although I haven’t experienced the “meditation state” some people mention.

Support Immune System

One of the best ways to fight off illness is to improve your immune system. Today, researchers are finding that L-theanine dramatically boosts the immune system. According to Medical News Today, there have been several reports that theanine reduces your risk of catching the common cold and flu. Also, L-theanine has possible anti-inflammatory properties that may help fight illness. 

Improves Sleep

Since theanine promotes relaxation, it is excellent for improving sleep. The studies also claim L-Theanine can improve sleep quality, even for people with attention and hyperactivity disorders such as ADHD. 

Personally, I can feel its calming effects. However, although I have experimented with theanine as a supplement, I do usually take it with caffeine. Caffeine, of course, increases your levels of cortisol and blocks adenosine, making you more awake – isolated theanine is a better bet for sleep.

Neuroprotective Effects of Theanine

Recent studies suggest that theanine has a protective effect on the brain. For example, many researchers have found that its properties may help prevent Parkinson’s disease.

Also, according to Science Direct, studies have shown that theanine may slightly improve cognitive dysfunction in the elderly. 

Antioxidant Properties

Many experts agree that L-theanine is an excellent antioxidant. It also inhibits lipid peroxidation, where free radicals can cause cell damage. Green tea and black tea are rich in antioxidants.

Theanine also has anti-inflammatory properties that can help decrease bladder hyperactivity and help prevent liver toxicity from stressors such as alcohol. Moreover, theanine is said to reduce inflammation and help lower oxidative damage generally, body-wide.

Theanine and Tea

Convinced that theanine is something you’d like to incorporate more into your diet? Want to know more about tea and theanine?

As mentioned, the best teas to drink for L-theanine are black, green, and oolong. Herbal teas generally do not contain theanine. 

Make sure you turn to one of the standard teas from a member of the Camellia family or a blend. And yes, decaffeinated varieties generally can leave a fair amount of theanine while removing much of the caffeine. Grab a decaf black tea to start if this is what you’d like.

Theanine and Caffeine

When taken together, caffeine and L-theanine are a great tag team. You’re already familiar with the effects of caffeine – more energy, increased focus, better mental acuity and performance, better recall. 

Thiamine powers caffeine up by reducing some of the “edge” – or anxiety – associated with caffeine. It also is neuroprotective in its own right and increases focus on the top of the caffeine.

You’ll probably agree (especially if you’re a coffee drinker), what you feel with a cup of tea is different from a cup of coffee even if the caffeine levels are roughly the same.

Ready to Try Some Theanine?

L-theanine has been gaining popularity among consumers, enthusiasts, and nutritionists – and for a good reason. A lot of the purported benefits of teas like green tea might be a reflection of theanine’s power.

The best way to take theanine depends on your lifestyle. As a start, try the effects of caffeine and theanine together naturally with a cup of black or green tea. For the more cutting edge among you who want to try it for athletic performance, you could try extract along with some high energy gummies as a pre-workout mix.

Either way, experiment a bit and let us know how it works out – do you get a smoother rush of energy and concentration than from other caffeinated drinks?

Gerard Paul writes about food and drink at ManyEats. While he drinks coffee most often, when he turns to tea, it’s usually a green.