What Are The Side Effects Of L-Theanine You Don’t Know?

L-theanine is a wonderful supplement to treat anxiety, stress, lack of concentration, and sleep disorders. It is an ideal supplement for all those, who want to have a sharp memory, better focus, and other cognitive skills. It also improves brain function, protects heart and blood vessels, reduces the risk of schizophrenia, enhances the immunity, heals stomach problems, promotes weight loss, reduces the depression symptoms, and the list goes on.  As it contains antioxidants, it also prevents liver injury. With oodles of advantages, not every product is 100% efficient, it also has some side effects. What are the side effects of L-theanine?

Before discussing the side effects of L-theanine, do you know the food sources of L-theanine? It is found in tea leaves come from the plant of Camellia Sinensis be it black, white, or green tea. It is the best source of L-theanine. Some daily life foods can also be taken to get the benefits of L-theanine.

It elevates the level of GABA, dopamine, serotonin, alpha brain waves, and brain calming chemicals while reducing the excitatory chemicals. In short, these changes in the brain promote calmness, reduce anxiety and stress, regulate mood, emotions, appetite, concentration, sleep, energy, alertness, improve focus, and make you more creative. Now you know enough about L-theanine, it is the time to know, what are the side effects of L-theanine? Here are some side effects of L-theanine

Adverse Effects Of L-theanine

Just like any other supplement, L-theanine also has some adverse effects. So, what are the side effects of L-theanine that you should know even before using the supplement?

Lowers Blood Pressure

This might be a benefit for many people, but there are many people, who didn’t find it a benefit, but a con. L-theanine has the ability to lower your blood pressure making it a side effect for the people with low blood pressure. Such people should take a lower dosage than normal people. The other best option is to talk your doctor about it and take expert advice.


The other side effect of L-theanine supplement is that it causes dizziness. Of course, not every individual experience, it but some people have complained about the dizziness.

Difficulty Concentrating

Again L–theanine is a supplement that goes well with most of the healthy people. They neither feel any discomfort, dizziness, or difficulty concentrating. It is known to enhance cognitive skills, especially when people combine it with coffee. It is also a fact that a few people experience brain fog when taken a higher dosage. So, the solution to this issue is to take the recommended dosage and combine it with coffee.


There are some people who have experienced nausea, and the reason could be combining the supplement with other substances such as caffeine or alcohol. If you are the one who feels nauseous after taking the supplement, then try to take a lower dosage. You can also change the time at which you used to take L-theanine. Don’t take it on an empty stomach if you experience nausea after taking one and make sure you don’t combine your L-theanine supplement with any other substance to avoid this issue.


It is the common side effect of L-theanine and a clinical research also confirms it. Most of the people experienced a headache, and they should take a lower dosage. You should also try taking the L-theanine supplement with caffeine as it helps reduce a headache. People who want to take higher dosage should also combine it with caffeine.


Some supplements can interact with L–theanine. It can be harmful to your health as it may increase or decrease the drowsiness and sleepiness. It may also affect the medicine’s effectiveness that you are taking for any other purpose. If you are already taking any medicines for any purpose, you need to consult your physician before using L-theanine. It can interact with high blood pressure medicines, stimulant medications, low blood pressure medicines, and supplements that contain caffeine.


In this ‘what are the side effects of L-theanine’ article, we shed some light on the some of the adverse effects that can cause a bit inconvenience or discomfort. It is better to consult your doctor before taking L-theanine.

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