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L-Theanine vs L-Tyrosine (+Can You Take Them Together?)

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Both L-Tyrosine and L-Theanine have a lot to offer and I’m a big fan of them both. But since they’re fairly similar in many ways, it might be hard for some people to choose between them.

Well if that’s you, you’ve come to the right place.

I started this Supplement Comparison Series for that exact reason. In each article, I take two types of supplement and put them head-to-head on pros, cons, price, my recommendations, and more to help you figure out which one to use.

In this piece, we’ll take a look at L-Theanine vs L-Tyrosine.

Here’s whether you should take L-Tyrosine or L-Theanine:

If you want to feel less stressed, improve your mood or increase your physical endurance, then you should go for L-Tyrosine. Whereas if you want to feel more focused and improve your sleep, you should go for L-Theanine.

What is L-Tyrosine?

Cheese on a cheese board

L-Tyrosine is a naturally produced amino acid that’s derived from another amino acid called phenylalanine.

It’s found in many high-protein foods, including chicken, turkey, fish and cheese.

(Fun fact: “Tyros” means “Cheese” in Greek.)

L-Tyrosine helps your body produce neurotransmitters like:

  • Serotonin
  • Dopamine
  • Adrenaline

An increase in these neurotransmitters help provide the benefits that L-Tyrosine promises to deliver.

(More on that soon…)

What is L-Theanine?

a field full of green tea leaves, which are  high in L-Theanine

L-Theanine is an amino acid found in tea leaves that’s popular for its “calming” properties.

So for most of us, tea is the most common source of L-Theanine.

(Well actually, real green tea if the most common source of L-Theanine.)

L-Theanine is among my favorite brain-boosting ingredients, as it’s safe, effective and healthy.


Benefits of L-Tyrosine

L-Tyrosine may help improve mood

A happy woman holding a balloon with a smiley face on it

L-Tyrosine is converted into dopamine, a neurotransmitter that controls pleasure and motivation.

(You know that great feeling you get when achieving a goal, like getting a promotion at work? Well thank dopamine for that.)

Dopamine also influences Serotonin, and the two together are thought to play a central role in regulating mood.

Research shows that L-Tyrosine may be able to help you if you’re feeling down in the dumps.

For example, a study showed that depressed women who took L-Tyrosine saw an improvement in mood.

When they switched to a placebo, the improvement disappeared and then when they went back to L-Tyrosine, the improvement returned.

This tells us that it was the L-Tyrosine that was responsible for the mood boosting effects.

L-Tyrosine may help boost exercise endurance

A cyclist in a competition

Running a marathon any time soon?

If so, you may want to give L-Tyrosine a try.

A study of 8 cyclists riding in the heat found that L-Tyrosine gave them a boost of energy, which helped them cycle further before they tanked.

It’s believed that this increase in endurance is due to increased dopamine activity, which improves exercise tolerance in the heat.

L-Tyrosine may help relieve stress & improve focus

A stressed out woman working on a laptop

Stress uses up your brain’s norepinephrine stores, and when these run low, your focus and memory suffer.

If you’re dealing with a lot of stress, then L-Tyrosine can help as research shows that it keeps your brain performing at its best during stress, and improves your focus during mentally challenging tasks.

In this sense, L-Tyrosine is similar to L-Theanine in that it works as a nootropic.

Benefits of L-Theanine

L-Theanine may help improve sleep

A woman sleeping in bed

I strongly believe that sleep quality is the most underappreciated aspect of living a healthy life.

So recently, I’ve been trying a few different supplements to help improve my sleep.

I’ve tried:

  • Holy Basil
  • L-Theanine
  • Phosphatidylserine
  • California Poppy Extract

My sleep was the best when either taking Holy Basil and Phosphatidylserine together or L-Theanine on its own.

(Truth be told, California Poppy Extract didn’t do much. It may be effective for other people, but me? Not so much.)

How did I know my sleep was amazing when using L-Theanine?

Well, I judge my sleep quality on 2 variables:

  • Sleep latency (i.e. how long it takes me to fall asleep)
  • Sleep depth (i.e. how deep my sleep is)

L-Theanine massively improved both of these variables for me.

L-Theanine may improve cognitive function

Like L-Tyrosine, L-Theanine acts as a nootropic.

For this reason, many people use it for its “brain enhancing” properties.

It seems to help cognitive function by amplifying your Alpha brain waves, which boosts creativity.

L-Theanine may reduce caffeine jitters

A cup of coffee on a table

That first sip of a warm coffee in the morning is utterly priceless.

You know what I’m taking about…

The one which puts a smile on your face even if it’s raining outside.

But every now and then, the caffeine rush that follows wipes that smile off my face faster than an avalanche disaster.

It can make me feel anxious, jittery and awkward.

But ever since taking L-Theanine alongside my morning cup of Joe, these effects are hardly noticeable!

(I know this is just anecdotal, but many other people have reported the same effect!)


L-Tyrosine Cost

L-Tyrosine is typically sold in capsules.

For a mid-range L-Tyrosine supplement, you can expect to pay around $22 for 100 capsules.

L-Theanine Cost

L-Theanine is usually sold as a powder or in capsules.

Typical prices for these are:

  • Powder: $10 for 100g
  • Capsules: $20 for 100

Side Effects

L-Tyrosine Side Effects

L-Tyrosine is generally recognised as safe by the FDA, however it may interact with certain medications.

So if you’re unsure, then please consult a doctor before supplementing with L-Tyrosine.

L-Theanine Side Effects

Like L-Tyrosine, L-Theanine is generally safe to supplement with.

However, those who consume too much tea (to get their L-Theanine) may notice the following side effects:

  • Nausea
  • Irritability
  • Upset stomach

These side effects are actually from the caffeine in the tea, rather than L-Theanine.


My L-Tyrosine Recommendation: NOW L-Tyrosine

NOW L-Tyrosine

Click to see on Amazon


A top quality L-Tyrosine supplement from a highly-respectable brand.

You can’t go wrong with NOW L-Tyrosine.

What I like about it

NOW are one of the very best supplement brands around and always produce only the finest quality supplements.

I know this is a fact for NOW L-Tyrosine as they use pharmaceutical grade L-Tyrosine in their capsules.

This basically means the L-Tyrosine is over 99% pure and contains no binders, fillers, dyes or other junk.

I also love how each bottle provides 120 capsules, so each purchase will last you many months.

Potential Drawbacks

Very few, although it would be nice to see more user reviews for the product.

Check price and read more reviews of NOW L-Tyrosine on Amazon.

My L-Theanine Recommendation: Nootropics Depot L-Theanine Powder

Nootropics Depot L-Theanine Powder

Click to see on Amazon


A brilliant powdered L-Theanine supplement.

Ideal for those who enjoy the freedom of choosing how much L-Theanine they want to take.

What I like about it

It’s refreshing to see that this supplement is 100% L-Theanine powder.

That’s right…

No cheap fillers, additives or preservatives you need to be wary of.

Just pure L-Theanine goodness.         

Another excellent feature is that each tub will last you many years as it provides a whopping 2500 servings.

(Is it just me who hates having to stock up on supplements every month?)

Also, it’s great that you can mix and match the dosage to suit your needs as some people will respond better at different dosages.

Potential Drawbacks

Well I guess being a powder can also have its drawbacks if people dislike the taste.

Although you can easily mask this with some juice or something, so it’s not a massive issue.

Check price and read more reviews of Nootropics Depot L-Theanine on Amazon.

Can You Take L-Theanine And L-Tyrosine Together?

There’s no scientific evidence to suggest that L-Theanine and L-Tyrosine taken together cause negative reactions.

Also, there are some nootropic supplements out there which contain both L-Theanine and L-Tyrosine, suggesting that you can consume them together.

That being said, we’re all biologically unique, and what’s safe for you isn’t necessarily safe for me. So if you’re unsure, you should always speak to your medical doctor.

L-Tyrosine vs L-Theanine: The Verdict

Thanks for sticking to the end of this L-Tyrosine vs L-Theanine breakdown with me.

Some of you may already know which of these you’re most suited to.

But if you’re still on the fence, here’s a high-level guide to help you decide:

You might prefer L-Tyrosine if:

  • You want less stress
  • You want to boost your mood
  • You want more exercise endurance

You might prefer L-Theanine if:

  • You want to be more creative
  • You want to improve your sleep
  • You love coffee but hate caffeine jitters

Hope this helped!


Friday 15th of October 2021

Hello I’m curious too if we can take them together but also what’s a safe dosage? From what I’ve researched is that it’s not harmful in large dosages but who wants to take that risk without knowing what amounts is the max or even the minimum. Also has anyone have any side effects from either of those?

Zuleika S. Caldwell

Tuesday 6th of October 2020

Can you take both at the same time?


Thursday 8th of October 2020

Some Nootropic supplements contain both of them, so I don't see why not.


Sunday 4th of October 2020

Good stuff! Thanks for taking the time to do this.

I've seen a lot of supplment brands that combine the two into one capsule, so what do you think about taking L-Theanine and L-Tyrosine together? Are you familiar with the combination?


Thursday 8th of October 2020

You're welcome Nathan :)

I'm not familiar with the combination, but it does sound like an interesting combo.

If you give it a try, let me know how you get on.


Wednesday 6th of May 2020

Thanks for analysis. Take the l Tyrosine in my thyroid health pill. Don't do caffeine(became allergic decades ago. Too much consumption). Love your comparisons! If you want to know my thyroid pills ingredients will forward. Has helped a lot.


Wednesday 6th of May 2020

Thanks for your comment Mary.

I've never actually heard of a Caffeine allergy before, that's interesting!

I don't actually suffer any Thyroid allergies, but thanks for the offer anyways.