The amino acid L-theanine can be found in teas, fungi and other foods. The human body creates protein using amino acids. For good health, the body needs 20 amino acids.

Combining these amino acids creates different proteins strands. They are the basic building blocks for life.

Theanine, a naturally occurring amino-acid, is similar to glutamate. Both are essential for nerve impulse transmission in the brain. Theanine acts in a very similar manner, as it helps with nerve impulse transmission and improves cognitive function. It can sometimes limit the effects of glutamate. This chemical may have an impact on other brain chemicals such as dopamine and serotonin.

L-theanine is a key ingredient in this. Nootropics, which are supplements that improve cognition and mental health, often contain it. The supplement is also used to relieve stress and anxiety. However, the data on its clinical use are not conclusive.

What is the l-theanine good for?

L-theanine has a number of promising applications, but more data is needed to be sure. However, we can only make some tentative claims.

Stress relief and anxiety treatment

L-theanine is shown to reduce stress and anxiety. Tea contains L-theanine, a component that has been shown to be relaxing in both studies and popular perception.

Data support l-theanine in this respect, at least to a certain extent. In several trials, l-theanine was linked to lower stress levels and anxiety among those who were experiencing negative situations. The effects of anxiety have also been reduced in those with schizophrenia and schizoaffective disorders, along with better management of symptoms.

Of course, more data is needed. At this point, you can be fairly confident that l-theanine is an effective anti-anxiety and stress-relieving supplement. This is why we see l-theanine in many nootropics.

Sleep quality

There are many studies that show l-theanine helps you sleep better.

In both animal and human research, it has been found that l-theanine doses between 250mg and 400mg can improve sleep quality. The 200mg dose of l’theanine has also been shown to reduce resting heart rate, which is a crucial component for relaxation and sleep.

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L-theanine can also help people with ADHD sleep better. A study focused on boys with ADHD diagnosed aged 8-12 who received two daily 100mg doses of L-theanine. After six weeks, they experienced longer and more restful sleep periods compared with a placebo group.

Similarly, l-theanine has shown potential for use in treating those suffering with schizophrenia-induced insomnia. The quality of sleep has improved for people with schizophrenia.

It will take more research to confirm that the effect is reproducible and that long-term l-theanine use is safe, particularly for children. It does appear to be incredibly promising. All of this points towards l-theanine being a potentially incredible sleep aid.

Attention and focus

The next reason why l’theanine is often used in nootropics formulas is that it shows great promise for improving focus and concentration, particularly when combined with caffeine or other stimulants.

In a small 2010 study, participants took a mixture of 97mg of ltheanine with 40mg of caffeine. (This is about two-thirds the amount of caffeine in one shot of espresso.) All participants were young adults who had to perform demanding tasks. The participants were found to have better concentration on tasks than the control group, as well as greater alertness and decreased fatigue.

Immune function

L-theanine can also improve immunity and immune function. However, the evidence is not very strong. In 2016, a study showed it could reduce infection in the upper respiratory system, while a 2011 report found that combining l-theanine with catechins (high quality antioxidants), from green tea can help to fight the flu.

There’s also a theory that l-theanine can improve inflammation in the intestinal tract, but more research is needed to confirm this.

Cancer Treatment

Some have linked l-theanine to an increase in the tumor-fighting effects of some chemotherapy treatments. L-theanine could make chemotherapy more efficient and effective at reducing cancerous tumors and fighting the disease.

Tea drinking is associated with a lower risk of cancer, but there has been no proof that this correlation exists. The exact mechanism is not known, but those who drink tea regularly experience lower rates of cancer. Women who drink regular green tea are 30% less likely than women who do not drink it to get pancreatic carcinoma. Many experts attribute this to the high l-theanine levels in green tea.

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Blood Pressure

It is a very big benefit, and relates to the ability of l-theanine to help you remain calm when under stress. This may keep your blood pressure low during stressful situations. Clinical data has confirmed this in part. In one study, l-theanine was shown to reduce blood pressure in those who were attempting mental stress.

This same study showed that caffeine could have an effect similar to nicotine, even if it is less intense.

Use of L-theanine can cause serious health problems

L-theanine can be used safely in most cases. There are some situations where you might want to be extra cautious. You should be aware of a couple side effects.

Side effects

There is no side effect associated with the consumption of l-theanine. Both as tea or a supplement, it is completely safe. Be aware that supplements are not regulated by the Food and Drug Administration. The FDA does not approve of supplements, nor do they look at them.

It is the responsibility of the producer to make sure that the supplements they sell are safe and high-quality, while it falls to the consumers to buy from reliable companies.

A few other things are worth mentioning. Teas that contain l-theanine may contain other ingredients which are not as helpful. In fact, they can be harmful for those who are undergoing treatment. Green tea polyphenol EGCG can reduce the effectiveness of bortezomib (a commonly used chemotherapy drug).

Always consult your doctor before changing or adding any additional therapies, and especially if you are undergoing medical treatment.

All things considered, supplementing with L-theanine should not be harmful. If you depend on green tea to get it as some do, then there may be side effects. Green tea with too much caffeine can cause mood swings, energy crashes and spikes, irritability and nausea.

If you’re pregnant or nursing, it is best to limit the amount of tea that you consume. Where possible, choose decaffeinated tea. It’s best to speak with your doctor prior to changing your supplement or diet regimen when pregnant.

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Theanine may have mild interactions with common blood pressure medications. As we’ve seen, theanine works to reduce blood pressure. Your blood pressure could drop too low if you take an antihypertensive medication.

You should also be aware of minor interactions if you are taking CNS-depressants or sedatives. The sedatives can make you sleepy and slow down your breathing. We have already seen that theanine can cause sleepiness and sedation. Although there has been no evidence that theanine and sedatives could interact in a way to enhance one another’s effect too far, you should still be cautious.

How to dose l-theanine

No dose has been established for l’theanine. Research is still in its early stages. It’s too early to draw any conclusions. Most studies used 200-400mg daily doses, and this seems to produce the desired effects.

But always be cautious. Consult your doctor if you are unsure of how to use l-theanine or the dosage.

Final thoughts

Since years, I have been using it passively. It’s because I am a huge fan of nootropics which include it in all of their formulae. It’s a fact that I question any nootropics which omit this ingredient.

It is because the product has a great deal of potential. This promise is largely based on its ability to reduce anxiety. The data is most convincing in this area. Even when faced with stressful situations on a regular basis, it should help you to remain calm and relaxed. It will also improve your sleep and focus.

There are also other benefits, which may be more specific – for example, treating schizophrenia, fighting cancer or ADHD. It is important to do more research. More research will always be welcomed. This allows for a greater level of assurance and reduced risk.

For the time being, however, it is safe to say that most of the l-theanine benefits are real. Its nootropic effects seem to be quite strong.

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