L-theanine – Latest Research Included

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L-theanine is a chemical that can help with sleep, thinking, and relaxation. It can also assist in losing weight and lowering blood pressure.

Studies suggest that L-theanine may have a number of health benefits, including improved concentration and sleep quality. It is naturally present in black and green tea and can be found in supplements.

This article provides a comprehensive overview of L-theanine's properties regarding its possible benefits, risks, and dose.

What is L-theanine?

The amino acid L-theanine can be described as an amino. Human bodies do not make this substance and it isn't necessary for humans. Black tea, green tea, and certain kinds of mushrooms naturally contain L-theanine.

L-theanine could alter the levels of certain chemical substances in the brain. They include dopamine and serotonin which affect sleep, mood, and emotions, as well as cortisol, which aids the body manage stress.

A shift in the chemical balance can alter an individual's mood and levels of stress.

Studies and tests conducted on animals have proven that L-theanine could provide many advantages. The experts believe it is generally safehowever there's currently a lack of rigorous research on humans to prove its advantages.

What are the advantages of L-theanine?

The following sections will discuss the evidence available to support the potential benefits of L-theanine.

1. Improved mental focus

Many consume green or black tea at work, believing it helps them focus their minds. A study conducted in 2012 confirms this belief.

Researchers found that people who consumed 100 milligrams (mg) of L-theanine made more mistakes on a focus task than people in the group that took a placebo. Consuming 50 mg of caffeine or mixing caffeine and L-theanine also helped improve people's concentration.

More research is required to determine how L-theanine affects an individual's concentration and attention.

2. Sleep better

L-theanine could help people to sleep better.

Numerous studies have indicated that L-theanine can aid people in relaxing before going to bed, sleep faster, as well as fall asleep more deeply.

These benefits could be due to the amino acid's particular effects on brain chemicals that play an important role in sleep.

A study from 2018 found that individuals reported greater satisfaction with their sleep after taking between 450 and 900 mg of L-theanine a day for eight weeks. Participants in the study had generalized anxiety disorder and were taking antidepressants.

The authors also noted that there were no improvement in insomnia or anxiety intensity.

3. Relaxation

A lot of people will consume a cup of tea or a hot beverage to unwind. Studies have suggested that the L-theanine found in teas of black or green may help in this state of calm by slowing down a person's resting rate.

4. Improved cognitive performance

In 2016, researchers reviewed the current research regarding the advantages of L-theanine. They concluded that the compound can help improve mental and physical well-being. It was noted to possess neuroprotective effects that improve brain function.

L-theanine can increase a person's focus and reaction time as a supplement. When combined with coffee, it could result in improvements in the capacity to focus and number of tasks. Caffeine is a stimulant, so it will help you remain alert and focused.

But, not every study has proven that L-theanine can enhance people's cognitive capabilities. It is necessary to conduct higher-quality research that can clarify the effect of this chemical on cognitive abilities.

5. Weight loss

In the diet that is calorie-controlled, replacing an unhealthy snack by drinking green tea, or a hot drink that is low in calories could help in weight loss.

The L-theanine present in green tea has the ability to produce a delicious taste, which is also known for its umami taste. Studies suggest that umami flavor could decrease appetite, which typically aids in weight loss.

6. Enhancing the immune system

L-theanine could aid the body's ability to fight diseases. A number of studies have shown that taking L-theanine can increase the body's immune system and make them less prone to contract common colds or the flu.

The anti-inflammatory potential of it can also aid in fighting diseases.

7. Reduced blood pressure

Research has found a link between the high blood pressure level to an increased risk of ailments, such as stroke and heart attack.

L-theanine is a natural stress reliever, and reducing stress and achieving greater relaxation can lower the heart rate. It can also aid in lowering blood pressure.

8. Supporting certain cancer drugs

Certain studies conducted on animals suggest that L-theanine can enhance the efficacy of chemotherapy drugs known as DoxorubicinThere is a possibility that L-theanine increases doxorubicin's effective through increasing the quantity of the drug that is present in cancer cells.

However, scientists have to study more thoroughly the precise interactions between these compounds.

What evidence do we have?

Although evidence suggests that L-theanine may help people's physical and mental well-being, further studies are required before doctors are certain of the true effects of this substance. Scientists have yet to conduct studies of high-quality in humans.

The majority of studies conducted to date been conducted with a limited sample which means that only a few people participated in the study. Results from a small amount of people is more likely to be inconclusive when compared to data from larger populations.

Some studies have also used animals, like mice or rats. However, humans tend to respond differently than animals, and the results might not be relevant to humans.

Is L-theanine safe?

Following expert advice, the FDA has classified the L-theanine ingredient as “generally accepted as inherently safe.” This implies that they believe in that the ingredient is secure when used as per the directions on the bottle.

However women who are pregnant or nursing should not take L-theanine.

Interactions and side effects

Most people won't suffer from side effects while taking L-theanine but it is possible that the supplement will be incompatible with certain medications.

It is important to talk with a physician about the current medication before taking supplements with L-theanine.

L-theanine is known to interact with following supplements and drugs:

  • medicines to treat high blood pressure
  • Other supplements that can reduce blood pressure.
  • stimulants, for example, that doctors prescribe to treat ADHD. These include stimulants such as those used to treat (ADHD)
  • supplements that have caffeine


L-theanine does not constitute a drug therefore there aren't regulations regarding the amount a person can take. But, it will not cause overdose.

L-theanine is available in 200 mg tablets. Before using these supplements, it is possible to consult a doctor for their recommendations regarding dosage.


Experts consider theanine generally safe to consume as a supplement; however, further research is needed to verify its health benefits. A few studies and studies on animals indicate that L-theanine may aid in relaxation, better sleep quality, and neuroprotection.

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