Started to take L-Theanine yesterday

I got agitation from Amisulpride which made me hard to concentrate on reading and writing. To alleviate the agitation I started to take L-Theanine yesterday. I took 200mg L-Theanine in the morning by opening the capsule and spreading the powder into my coffee. This supplement was not a wonder to me but I did feel a bit calmer and more relaxed. I could sit still reading and thinking for 5 hours. Usually I could only do this 1 to 2 hours. So there was a big improvement.

But L-Theanine has drawbacks. It made me wake up much earlier than usual. I woke up 6 am today which was 3 hours earlier than usual. Also I felt a chest pain when I woke up. I know this kind of chest pain very well. I know this chest pain came from my heart as I have a history of cardiovascular problems. I suspect L-Theanine changes something in my blood.

I will post more about the experience of taking L-Theanine.

@green5… Keep updating…

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I’ve read a short article about L-theanine today. It says L-Theanine reduces heart rate and lowers blood pressure. So I suspect my heart needs a fast rate to supply enough blood to my body and when L-Theanine reduced my heart rate my heart had to work harder with each pump to meet the needs of my body. That may explain why I felt uncomfortable with my heart.

Just a vague guess.

How much does that cost? I might try some.

There are different L-Theanine products on iherb online shop, varying from 100mg to 200mg and different brands. I bought Source Naturals brand 200mg at the price of $16 for 60 capsules.

The powder is much cheaper than the pills.

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This is the 3rd day since I started taking L-Theanine. The reaction from my heart is gone. I still woke up early around 6am but was able to get back to sleep quickly. The new problem is I found it’s hard to get up as I was so drowsy. I got out of the bed at 11 am !

I will keep taking this supplement for one week. Let’s see what I get tomorrow.

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This afternoon I started feeling a pain in the back of my head. This pain lasted for long.

headache is a common side effect of L-theanine.

Hey @green5 I would maybe stop taking it if you are getting so many side effects. Talk to doctor at the very least - chest pain is not to be messed with.


I agree. That doesn’t sound right.

To @Jimbob and @everhopeful My body has been very sensitive to drugs and supplements, and it needs to overcome a period of discomfort and then get used to the new drug or supplement. For example, my body reacted violently to zyprex, Risperidone and Seroquel. I became suicidal the first day I took Zyprex and became severely depressed for one week during the second month. But after that my body started to tolerate Zyprex and it became an excellent antipsychotics for me. So I’d like to give L-theanine a chance of 7 days, but I may adjust the dose from 200mg to 100mg…


@Jimbob @everhopeful I got horrible side effects from Sarcosine and I stoped taking it finally. My body rejects most of the supplements I have tried.

OK, keep an eye on things. If I got chest pains from a supplement, I’d stop taking it, but at the end of the day you know yourself the best.

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Thr 3rd night was awful. I had a migraine. There was a jittery feeling inside of my brain. The whole night I was half awake and half asleep. I know L-theanine is building up in my system and my body rejects it.

Apparently 200mg L-theanine each day is too much. I decided to stop for 2 days and after that I’am going to try 100mg L-theanine daily.

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Well, good luck @green5

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Yes - everyone is different with these supplements. Some people here take 300mg+ a couple times a day, and others take less with good results. Some see no results. Let us know how it goes. and thanks for posting your results so far.

I started to try L-theanine again yesterday. Instead of 200mg , this time I took 100mg. Didn’t feel much effect afterwards. But I had bad sleep last night as I could not fall asleep.

I am a bit scared now, don’t know if I should continue the experiment.

Hi green6, the pains in your chest could be heartburn. L-theanine is known to cause heartburn. I take omeprazol for heartburn and my chest pains have gone. L-theanine comes from green tea and green tea can cause heartburn. L-theanine extract is like drink 40+ cups of green tea, which will cause heartburn in some people. I’m not saying you have heartburn, but you could, and that’s what happened to me, I thought I was gonna die from a heart attack but it was only serious heartburn. But I would get yourself checked out… To be on the safe side.

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Nah. If in doubt, stop taking it.