L-Theanine is an amino acid with calming and relaxing properties that can be found in many brain supplements today or in tea. Theanine improves mental performance and calms anxiety symptoms. Tea is one of the most popular beverages in the world. Drinking tea has many health benefits and because of that tea has been highly valued in China and Japan for hundreds of years for its ability to stimulate mental clarity, increase physical stamina, and promote a long and healthy life. Tea contains close to 1,400 chemical compounds, and of all these compounds, L-Theanine stands above the rest for its ability to slow down mental aging and improve overall brain health.
Common Question: What Is L-Theanine?
L-Theanine (best known as just Theanine) is an amino acid that is well regarded for its relaxing, but not sedating, effects. The amino acid is quite uncommon in nature and is available almost entirely in pure teas – such as green teas, black teas, white teas, and oolong – which originate from the leaves of the same evergreen bush, Camellia Sinensis. The amino acid also exists in a mushroom called Boletus Badius. Boletus Badius is not something you’ll buy at your local supermarket, but it can be found in the conifer forests of northeastern North America, and sometimes in northern beech-maple or birch forests.
Many experts claim that L-Theanine is available in green tea only or that green tea is by far richest source of it. This claim is not really accurate. Yes, the amino acid is commonly linked with green tea because that’s where it was initially discovered. But recent clinical studies on Theanine concentrations in various teas have shown that the amino acid exists in almost equal amounts in white, black, green, and oolong teas.  In fact, L-Theanine is responsible for the famous “tea’s umami,” a particular tea flavor which is regarded as the fifth taste sensed by humans. Unlike many vitamins, herbal extracts, minerals, and even other amino acids, L-Theanine can easily cross the blood-brain barrier (BBB), making it a highly regarded ingredient in most brain supplement formulas.
6 Ways L-Theanine Improves Cognitive Performance
L-Theanine provides numerous brain benefits, and it’s universally appreciated for its ability to induce a state that’s been known as “calm attentiveness” or “focused relaxation.”
Here are six specific benefits of L-Theanine for insomnia, stress, cognitive performance, anxiety, and general health.
1. Treats Anxiety and Relieves Stress
The consumption of L-Theanine may increase body’s resilience to stress by improving physiological and psychological stress responses.  It can help you maintain healthy blood pressure and decreases your heart rate when you are under stress.  L-Theanine reduces anxiety’s symptoms by improving GABA’s levels, a neurotransmitter that plays a central role in relaxation.
When GABA levels are depleted, it becomes impossible to quiet your mind, and you may often feel overstimulated and overwhelmed. Studies show that L-Theanine can work just as well to reduce anxiety as commonly prescribed medication.
In one recent study, participants were given either the anti-anxiety medication Xanax or L-Theanine. Then, participants were subjected to artificially induced stress. Those who received L-Theanine had lower baseline anxiety than those who took Xanax. Moreover, when L-Theanine is combined with antipsychotic medication, it can reduce the anxiety symptoms of schizophrenia. 
2. Boosts Critical Brain Chemicals
There are many ways L-Theanine can benefit the brain, but one of the most important ones is by supporting neurotransmitters, biochemicals that neurons use to communicate with each other. The amino acid boosts the levels of some of the most important neurotransmitters, especially dopamine, serotonin, and GABA, thus improving learning, recall, and positive mood.
By inhibiting the dopamine reward pathway, L-Theanine has been shown to help smokers quit smoking. An intriguing and unexpected benefit of L-Theanine is that it acts as a neurotransmitter in the brain even though the body doesn’t naturally produce it. Theanine also increases two other essential brain chemicals: nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). Both can stimulate the growth of new brain cells and neurons.
3. L-Theanine and Caffeine Can Boost Cognitive Abilities
Besides L-Theanine, tea also contains caffeine. And fortuitously for us, these ingredients work well together when you consume tea.  A mixture of caffeine and L-Theanine can help you do better on cognitively demanding tasks than caffeine alone, yet will leave you less agitated since L-Theanine turns down the overstimulating effects of caffeine.
It’s this unique caffeine-enhancing property that makes L-Theanine such a well-regarded supplement for those seeking improved mental performance such as college students, biohackers, and workers in high-pressure jobs. And as the supplement industry has proven us, a combination of caffeine and L-Theanine can be a potent nootropic “stack” for boosting focus, mood, alertness, and concentration. L-Theanine, mainly when used with caffeine, could prove a safe and effective way to enhance cognitive performance without resorting to prescription medications or potentially dangerous brain stimulants.
4. Induces a Relaxed Brainwave State
L-Theanine can alter your brain waves, inducing a state of calm and relaxation. Your neurons generate electricity to communicate with each other, and this electrical activity forms patterns called brain waves. There are five main brainwave patterns, each corresponding to a different state of sleep. L-Theanine causes an improvement in alpha activity, the brainwave state linked with attention and relaxation. Coincidental or not, this is the same brainwave state people reach during meditation.  So you can experience benefits comparable to meditation by taking a standard supplemental dose of L-Theanine.
5. It is Neuroprotective
L-Theanine protects the brains of elderly and helps keep them mentally sharp. Studies in traditional tea-drinking countries like China and Japan showed that seniors who regularly drank tea scored better on attention, memory, and information processing than those who did not.
L-Theanine has been shown to improve cognition and memory, even in people diagnosed with a type of cognitive decline known as MCI or mild cognitive impairment. Theanine has been shown to offer some additional layer of protection to the brain against stroke and Alzheimer’s. It can also help prevent neurons death following a transient ischemic attack, which is a type of stroke. 
Theanine can also protect the brain from environmental neurotoxins which are believed to play a role in Parkinson’s disease. One way this powerful amino acid may help slow down mental decline is by increasing blood flow to the brain.
6. Improves Sleep Quality
One last benefit of this amino acid is that it can improve sleep quality, which is important because getting high-quality sleep is one of the best things to do for your brain. It’s during sleep that your brain grows new brain cells, repairs itself, and consolidates the memories of the day. Unlike the many natural sleep remedies which will only make you drowsy, the amino acid doesn’t put you to sleep, but it can help you sleep better.
Another recent clinical study revealed that 200 mg of L-Theanine before bed might dramatically improve sleep quality. And unlike many other sleeping aids, it won’t leave you feeling tired the next day. Most experts agree that too few valid studies have been carried on the effects of Theanine-based supplements on humans and that drinking tea is still, most likely, the best way of getting your daily dose of L-Theanine. However, you can expect to get only about 25 mg of pure Theanine from a cup of tea while high-quality supplements contain up to 200 mg per serving.
Drinking that much tea, even decaffeinated, would require you to drink much more than the recommended amount of tea.
So What All These Mean?
Tea is, without question, one of the healthiest drinks available, and L-Theanine is responsible for many of tea’s benefits. The amino acid is highly regarded for its unique ability to make you feel calm and focused without drowsiness. It can improve your mood and your ability to focus and concentrate.
This potent amino-acid can boost brain health and function now, and help prevent mental decline in the future. It can help you get the restorative sleep your brain needs to function its best.
You can get your L-Theanine from supplements or from drinking tea – black, green, white, or oolong tea; all containing significant amounts of this amino acid. But since both tea and supplements bring their unique benefits to the table, and high-quality supplements contain no caffeine in their formula, there’s no reason you can’t drink tea and take a Theanine supplement.