L-Theanine Benefits

L-Theanine Benefits

In 1949, Japanese scientists identified l-theanine benefits while studying green tea leaves. Their actual purpose in doing this research was to find a source of umami found in other foods such as fish, mushrooms, some vegetables, and some meats. They discovered that l-theanine is the source of the umami, which is the savory, frothy flavor found in Earl Grey Tea.

However, in searching for umami, they made some other interesting discoveries. They believe umami to be instrumental in decreasing the risk of obesity in some people. Additionally, it stimulates the metabolism while giving a feeling of being full. Moreover, the time before the sensation of hunger returns lengthens considerably.

Interestingly, their findings also indicate that when you drink tea with l-theanine, it might change your taste buds, in that it diminishes bitterness in foods like grapefruit or dark chocolate.

Ancient Uses of Green Tea

Ayurvedic medicine uses green tea for its abundant antioxidant qualities, but the caffeine in green tea is not good for everyone. This practice also believes that green tea balances out stimulants and stress.

Traditional Chinese Medicine (TCM) uses green tea to improve many illnesses, including; alertness, ability to support immunity, balance body fluids, and can promote healthy digestion.

Introduction to L-theanine Benefits

L-threonine is an amino acid that affects the release of neurotransmitters in the brain, including GABA. The effectiveness of this supplement includes its ability to quickly cross over the brain barrier, and carries with it proven neuroprotective qualities. Incidentally, this compound can be found not only from tea leaves, but you will also find it in some types of mushrooms.

L-theanine benefits include a reduction in anxiety, hyperactivity, and sleep-related issues. You will also see reference to it as theanine or r-glutamyl-ethyl amide. Interestingly, it works by impacting nerve impulses in the human brain with the release of neurotransmitters, one of which is GABA.

Furthermore, l-theanine is a natural anxiolytic, which means that it not only delivers a calming effect, but it also does it without the side effect of drowsiness.

Unlike other amino acids, it doesn’t form protein in the body, and it doesn’t contribute to enzyme production. Additionally, it isn’t available in most of the foods that people normally eat. Unfortunately, that means many people have unhealthy levels of l-theanine in their bodies.

The most readily available sources of l-theanine are green, black, and white teas. However, supplements are also available, and effective, in reducing stress, supporting good heart health, and protecting the brain.

Its relaxing qualities come from its ability to inhibit, or block, cortical neuron excitation. More specifically, it affects the two areas of the brain, the amygdala, and the hippocampus, that control memory and responses to fear.

L-theanine Benefits and Effectiveness

Alpha Brain Waves Increase

Alpha brain waves are what the brain produces when you meditate or reach a certain state, during aerobic exercise. Because l-theanine promotes a healthy, relaxed state of mind, some believe that it also aids in the production of alpha brain waves for deep relaxation, and meditation.

Antioxidant Qualities

One of the best l-theanine benefits is its antioxidant effects. As an antioxidant, it prevents oxidation of low-density lipoprotein (LDL) cholesterol. This gives excellent protection for the cardiovascular system.

Anxiety and Stress-Related Issues


A lot of research is available showing l-theanine’s ability to relieve stress, and improve relaxation. You won’t feel tired or lethargic from taking this supplement, but you will enjoy relaxing, while remaining alert.

If you suffer from stress issues, such as anxiety and depression, this supplement is worth further research. That’s because l-theanine reduces stress-related blood pressure spikes. However, it’s not suggested for the treatment of extreme anxiety or depression.

Cancer and Tumor Treatment

As mentioned before, l-theanine is also found in some types of mushrooms. In one study with the Bay Bolete mushroom, when used in combination with certain chemotherapy drugs, it worked to increase their effectiveness. These findings also give researchers hope that l-theanine might also improve chemotherapy drugs’ ability to fight cancer.

Another study performed in China, showed greater longevity of life for women with ovarian cancer, who drink at least one cup of green tea per day.

Additionally, a study that compares tea drinkers, to non-tea drinkers, showed a 37 percent less chance of developing pancreatic cancer among the tea drinkers.

Cardiovascular Health

The number one source of l-theanine is green tea, and research shows that it greatly reduces inflammation, and supports good heart health. Interestingly, experts attribute this protection to theanine, rather than catechins or theaflavins found in green tea.

Additionally, stroke victims may also get great l-theanine benefits. A study on rats suggests that subjects given l-theanine, 12 to 24 hours after a stroke, showed damage reduction.

Amazingly, in a study that used roundworms, it’s shown to increase the longevity of life, when exposed to high concentrations of l-theanine. However, an increase in thiamine did provide more benefits, while a lower dosage was found to be the most effective.

Immunity Support

If your immune system is showing signs of damage due to stress, you might find yourself getting sick more often. That’s because stress affects immune cells, and activates others. However, l-theanine gives a big boost to immune system cells.

Research also suggests the improvement of the body’s immune system. A study showed that upper respiratory tract infections decreased with the use of l-theanine.

Memory Improvements

In another study, patients were given a combination of green tea extract and theanine (LGNC-07). The results indicated that memory and recognition were improved, with no negative side effects on visual-spatial working memory.

Mental Focus Improvements

It’s no secret that many people drink green, or black tea, to boost their mental focus. In fact, a study done in 2012, showed evidence of this. One group who took 100 mg of l-theanine, they found better focus and fewer errors.

Additionally, in that same study, focus showed improvement when drinking 50 mg of caffeine, and when taking a combination of caffeine and l-theanine.

Neuroprotection for the Aging Brain

But, there’s another way this supplement helps protect the brain. Interestingly, it prevents glutamate over-stimulation of brain cells, also known as excitotoxicity.

Sadly, excitotoxicity is associated with schizophrenia, stroke, and other neurodegenerative disorders. The good news is, by blocking the effects of glutamate, l-theanine provides protection for the aging brain.

PTSD and Mood Disorders

A study on rats measured the effects of l-theanine on post-traumatic stress syndrome (PTSS). This study suggests that l-theanine seems to affect the levels of neurotransmitters, which results in gene changes that could be important in the treatment of PTSS, and other anxiety, and mood disorders.

Schizophrenia Symptom Reductions

When given a dose of 400 mg, one study suggests that the anxiety and activation symptoms of schizophrenia showed reductions.

Sinusitis Relief

When the cilia (or hair-like strands) in our sinuses are no longer able to pulse to remove mucus from the nose and sinuses, sinusitis occurs. According to Murray Grossan, MD, l-theanine boosts cilia movement, and therefore speeds healing of sinusitis. Tip o’ the Hat to Grossan Institute.

Sleep and Relaxation Improvements

Because of its inherent relaxation qualities, l-theanine helps people fall asleep more easily, and sleep better for a longer period of time. A recent study where elderly test subjects were given low-caffeine green tea, suggests that it might be beneficial for improvement in the quality of sleep.

As the disturbance of sleep is a symptom of dementia in the initial stages, this may be a therapeutic tool for a healthier, better quality of life for Alzheimer’s patients.

In a trial study using boys who were 8 to 12 years of age, after six weeks, those taking l-theanine had longer, more restful sleep. However, you must consult with your medical professional before giving this, or any other supplement, to a child.

Additionally, there is a study that suggests that schizophrenia patients’ sleep improved while taking l-theanine.

Stress Reduction

This supplement is also excellent for stress reduction, due to its inherent relaxation qualities. In 2007, Japanese scientists found that l-theanine greatly reduced blood pressure spikes, after a traumatic event. The research also indicated a reduction in rising heart rates, due to stress.

Weight Maintenance

With its relaxing anti-anxiety qualities, this supplement also makes it easier to lose excess weight. Evidence indicates that l-theanine plays a part in weight maintenance, as it helps the body resist obesity.

L-theanine Negative Effects

The FDA classifies l-theanine as “generally recognized as safe.” Overall, healthy adults have no side effects from l-theanine. However, there are circumstances where people should first consult with their medical professional before taking this supplement.

Below you will find a list of conditions in which consultation with your medical professional is important before taking l-theanine. Take precautions against l-theanine side effects by noting the following:

  • Pregnant and lactating women
  • People with low blood pressure
  • Non-adults (children and teens)

Combinations to Avoid

  • Other supplements that lower blood pressure
  • Stimulants that treat ADHD
  • Other supplements that contain caffeine

Additionally, consuming a large amount of green tea will cause you to suffer from irritability or nausea.

Medication Interactions to Avoid

Even though research shows some promise of cancer-fighting qualities, some teas have amino acids that might be harmful to people with cancer Therefore, it is wise to check with your medical professional before using this supplement.

If you take any of the following medications, consult with your medical professional before taking l-theanine. Not doing so might result in unpleasant l-theanine side effects.

  • High blood pressure medications. Taking these with l-theanine may cause your blood pressure to go too low.
    • Captopril
    • Capoten
    • Vasotec
    • Cozaar
    • Diovan
    • Cardizem
    • Norvasc
    • HydroDiuril
    • Lasix
  • Stimulant medications. Taking these with l-theanine might slow down the nervous system and decrease the effectiveness of the stimulant.
    • Tenuate
    • Lonamin
    • Sudafed

L-theanine Dosages

For an excellent anxiolytic effect, use 200-250mg daily. L-theanine is available over-the-counter, usually in 200mg tablets.

One study showed a combination of 97mg of l-theanine, and 40mg of caffeine, was helpful for young adults participating in demanding tasks.

There are no reported overdoses of people drinking tea, but it’s still wise to follow the same precautions for safe caffeine consumption.

Healthy Ways to Use L-theanine

Green tea is the most common and easiest way to incorporate l-theanine into your daily diet. So, try drinking one cup per day to start, then if you wish, add another cup. Safe limits are 1 – 4 cups of green or black tea per day.

If you wish to take tablets, take 100–200mg of an organic table supplement 1–2 times per day. Furthermore, l-theanine is safe to take with, or without meals.

Tip o’ the Hat to PaleoHacks

L-theanine Review

In review, l-theanine benefits come from an amino acid discovered in 1949 by Japanese scientists in black and green tea. It helps with relaxation, focus, and anxiety. It also helps to lower blood pressure, and increase mental alertness. Additionally, it also provides some release from stress.

The unique quality of l-theanine to increase relaxation without drowsiness, makes it an excellent choice for anti-anxiety and stress relief. Moreover, it actually increases alpha waves in our brains, which produces the best relaxation. Amazingly, it also produces a meditative state of mind, for even deeper relaxation.

Other l-theanine benefits also include better mental focus, improved sleep and cognitive performance. Additionally, many people find that drinking green tea aids in their weight management. Moreover, it reduces blood pressure, while boosting the body’s immune system.

Natural sources of l-theanine include:

  • Bay Bolete Mushrooms
  • Black tea
  • Green tea
  • White tea

Interestingly, younger tea plants have a higher level of l-theanine than more mature plants.

L-theanine increases the effectiveness of GABA, which is the body’s neurotransmitter. It is also found to increase alpha brain waves, causing relaxation, and improvements in cognitive and creative abilities. In addition, glutathione levels increase.

The beauty of l-theanine, is that it gives nice relaxation effects, without the drowsiness. Its ability to easily cross the brain barrier, makes it highly effective and fast-acting. Additionally, it may be an alternative to prescription anti-anxiety medications. Tip o’ the Hat to NootroNerd

Continue to do your research into l-theanine benefits, if you believe they might fit into your lifestyle. Always consult with your medical professional before starting any supplement regimen, and remember to read the manufacturer’s labels carefully.


These statements have not been evaluated by the Food and Drug Administration. Products discussed are not intended to diagnose, treat, cure, or prevent any disease.