side effects l theanineIf you’ve ever heard about all the beneficial effects of L theanine, you´re probably curious if there are any downsides to taking this supplement. You´d likely ask yourself the question `what are the side effects L theanine?`.

If you want to know the answer to this question, then please continue reading. I’ll explain you all the side effects l theanine has. You’ll be surprised…

Side effects L theanine

L theanine is a great supplement if you’re looking to reduce stress enhance focus and concentration, or if you’re suffering from anxiety attacks. It’s an amino acid that helps you produce the calming neurotransmitter GABA. This causes your brain to relax and you will feel calmer.

Now you’re probably thinking: a supplement with that many benefits probably has some negatives to it,, right? Well, that’s what you would think. But did you know that…

Theanine has no real side effects

That’s right. Research is very clear on this. There are no real side effects L theanine has. Now, with real side effects I mean things like hypertension, damaging your liver, and other things that can be really bad for your health.

However, L theanine is not something that I recommend you take every day in unlimited quantities. Not because it can be dangerous for your health, cause it’s not (even if you take as much as you want)

Note: with the supplement L theanine your body takes as much theanine as it needs. The rest you will excrete through your urine. So, it’s safe to take theanine. however, taking more than your body needs, is a waste of supplement. I therefore recommend you take around 200-400 mg per day maximum!

There are a couple of things you need to watch out for

So, it’s safe to take it everyday. You won’t damage your health nor will you feel bad. Then why am I saying that it’s better to watch out with this supplement? Well, the answers are simple. It can reduce the effect, or you could get too used to taking theanine.

I know that for me, when I’m taking the supplement to increase my focus and concentration. If I’m taking it more than 4 days, I get too used to L theanine’s effect. This in turn diminishes the focus-enhancing effect.

l theanine focus
If you’re taking L theanine for focus enhancement – I recommend you don’t take it more than 4 days in a row.

So, here are my L theanine dosage recommendations:

Don’t take it every day

As I said before, don’t take L theanine every day. Especially if you take it for focus enhancing benefits. the reason for this is clear. If you take it every day, your brain and body will start to get used to it. And it will be less effective.

However, another thing I’ve noticed is that the anxiety reducing effect does not get less if you take it for a longer period of days. So, if you suffer from anxiety and that is the reason why you’re taking l theanine, then feel free to disregard the advice I gave in this paragraph.

Don’t take too much at once

Another thing that you should watch out with is taking too much L theanine at once. Again, this is not dangerous for your health. But it can make you very sleepy.

if you’re suffering from insomnia, then this is obviously a great thing! But if you still need to drive somewhere, then the last thing you want is a supplement that makes you sleepy.

l theanine dosage
I usually take 150 mg (a tablespoon) of theanine

Dosages that I consider ‘too much’ depend on how your own body reacts to L theanine of course. but I’ve found that for the average guy taking more tan 500 mg of theanine at once is more than enough. Any more and you risk feeling very sleepy. If this is your goal, then there is no problem of course!

Get quality L theanine

The last thing you need to watch out for is that you get quality L theanine. Since this supplement is becoming more and more popular every single day, there are also more and more producers of L theanine on the market.

Most of them use tested L theanine from some of the bigger manufacturers out there (Suntheanine comes to mind), but some of them do not.

I highly recommend you check the manufacturer from the theanine that you’re about to buy.

So far, I’ve found that the theanine is of good qaulity with the following producers:

  • Every theanine brand that is made from ‘Suntheanine’
l theanine myprotein
You can find quality L theanine at Myprotein,.com

If you’re unsure if the theanine that you bought is of high quality, feel free to leave a comment with a link to where you bought it.

Final words side effects L theanine

Since this is one of the shorter articles on this site, I wanted to do a quick recap of everything we just discuss about the side effects L theanine. Here’s the summary of this article:

  • L theanine has no real side effects. It’s not dangerous for your health. Science has confirmed this.
  • Your body only uses the amount of L theanine that it can use. The rest your body will just excrete through urine.
  • But there are a couple of things that you have to watch out for:
    • taking theanine every day can reduce its effectiveness if you take it for concentration enhancement
    • if you take too much theanine at once (500+ mg), then you can start feeling very relaxed and possible sleepy. Watch out if you still have to drive or do anything else that requires your full attention.
  • Always be sure to check the manufacturer of the theanine. Everything containing Suntheanine or from is alright.

So, that’s it for the side effect L theanine. If you have any questions about how to use l theanine, other benefits of this supplement, or a general comment about the site. Then feel free to leave a comment! I’d love to help you out with any issue that you have concerning theanine or any other supplement!


P.S. want to know  everything about all the benefits that theanine can give you? Read my L theanine review here  & find out!

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  1. I suffer with chronic asthma and am wondering if this will affect my breathing at all. I only have 38% lung capacity so cannot afford to have an attack.

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