Everything You Need to Know About L-Theanine

L-theanine is a amino acid found in only a handful of foods.

If you've already taken steps to create a nighttime routine and reduce stress, yet you still struggle with insomnia and anxiety that interferes with your sleep, this may be a supplement worth adding to your repertoire.

Let's take a deeper look at this unusual amino acid and its effects on sleep quality and cognitive function so you can figure out if its right for you.

What is L-Theanine?

l-theanine in green tea

First discovered in 1949 by Japanese scientists, theanine (1) is an amino acid that you'll typically find in all types of tea leaves (except herbal varieties):

  • green tea or green tea extract
  • black tea
  • oolong tea

Some mushrooms also contain trace amounts.

L-Theanine is the reason you feel calm and relaxed yet mentally alert after drinking an afternoon cup of tea.

We'll explain deeper later, but caffeine and theanine have an interesting synergistic effect on the brain.

L-Theanine is an interesting amino acid because it crosses the blood-brain barrier and has an interesting effect on mental health.

To top it off, experts believe l-theanine is a natural source of umami -- a savory flavor enhancer.

You can find this amino acid in supplement, powder, and liquid forms.

What are the Health Benefits of L-Theanine?

l-theanine in oolong tea

Although l-theanine isn't an essential amino acid, that doesn't mean it can't improve your health.

The effects of l-theanine on mental health are vast and can reduce psychological stresses on multiple levels.

Let's have a look at the most well-documented health benefits.

L-Theanine May Improve Sleep Quality

Theanine appears to improve objective sleep quality even in folks with mental health disorders like schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder (ADHD). (2, 3)

Studies show that theanine doses of 200 to 400 mg can reduce your resting heart rate and encourage healthy relaxation, so it's easier to fall asleep.

If you're suffering from insomnia, try taking some theanine capsules an hour or two before bedtime.

May Reduce Anxiety Symptoms and Improve Mental Health

mental growth

Double-blind studies show that theanine is an anxiolytic that appears as effective as Xanax for reducing anxiety symptoms and promoting relaxation. (4)

The best part is that theanine can reduce anxiety symptoms without the same unwanted side effects as Xanax like drowsiness. (5)

If you feel overwhelmed with anxiety symptoms that push you over the edge and interfere with your ability to focus, you may want to consider including a theanine dietary supplement to improve your stress response.

Of course, anxiety is a serious condition, and any protocol should be reviewed by a qualified mental health practitioner.

May Lower Blood Pressure Levels

When you face a stressful situation like traffic during your commute or challenges at work, your blood pressure rises.

That's why medical advice for people who are at risk of heart attacks includes reducing and managing stress.

Now, it's always a solid idea to take measures to reduce your stress. However, theanine can also offer some support as a dietary supplement.

Studies show that l-theanine can improve your stress response by regulating blood pressure during stressful moments.

May Improve Cognitive Function

cognitive function

Studies show that l-theanine can boost alpha brain waves -- especially in folks prone to anxiety -- which promote hand-eye coordination, learning, calmness, and focus. (6)

Although it's an amino acid, l-theanine almost functions as an adaptogen in terms of reducing psychological stresses and improving your stress response.

When you're in a stressful situation, your body produces hormones like cortisol and corticosterone. These hormones interfere with your ability to focus and make proper decisions.

When you take l-theanine, it can reduce your stress hormone levels so you can focus better. (7)

Finally, l-theanine offers added nootropic benefits when you combine it with caffeine, but we'll get to that later.

Can Support Healthy Weight Loss

Psychological stresses do more than destroy your ability to focus.

Poor sleep quality combined with high cortisol levels can lead to weight gain in dangerous areas around your midsection.

By balancing blood pressure, supporting cognitive function, and improving your stress response, theanine can also support weight loss efforts.

What You Should Know About Combining L-Theanine and Caffeine

beverages l-theanine and caffeine

L-Theanine and caffeine create a nootropic powerhouse.

We've all been there: You're feeling tired from a poor night's sleep, so you pound caffeine through the morning.

The next thing you know, you're a ball of anxiety, jittery, and you don't even feel focused or awake!

L-Theanine is great because it can help balance the effects of caffeine intake.

Since l-theanine impacts your GABA levels and crosses the blood-brain barrier, it can help you enjoy the alert feelings of caffeine without feeling anxious or stressed.

Remember when we mentioned that green tea makes you feel alert and energized yet calm and relaxed? The unique green tea components of l-theanine and caffeine is exactly why.

What are the Side Effects of L-Theanine?

This amino acid appears safe with no adverse effects in doses up to 1,200mg per day (although we don't recommend taking that much).

Most people take 100 to 200 mg of theanine in capsules or mix it in powder form into their coffee to balance the effects of caffeine.

If you take capsules, it's a good idea to take your morning l-theanine about 30 minutes before you start sipping your coffee.

You can take this combination of l-theanine on an empty stomach without any food to aid absorption.

Although there aren't any known side effects of l-theanine, you should still talk to a doctor before taking it as a dietary supplement if you struggle with low blood pressure or take any medications to lower your blood pressure.

Since theanine can regulate blood pressure, even during stressful moments, it could drop your blood pressure to dangerous levels if you're already taking a medication for the condition.

The Bottom Line

L-Theanine is a somewhat rare amino acid mainly found in tea leaves like green tea and black tea, as well as some mushrooms.

Since it's extremely safe with no known adverse effects, easy to find, and essentially flavorless, it's easy to experiment with theanine as a dietary supplement.

Take a few capsules before your morning cup of coffee and see how it works to boost cognitive performance and reduce anxiety with your caffeine intake!

About the Author

Tegan Shields

Hi, I'm Tegan. I have a degree in Nutrition and Food Science and a deep passion for real food and natural health. I am a huge believer in the power of mushrooms, and want to help you get some in your life!

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