‘I’m a Happiness Expert, and Here’s Why L-Theanine Is One of the Best Mood-Boosting Nutrients for You’

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Figuring out what it takes to be happy isn't easy. It's a question that humans have been asking since the beginning of time and there isn't one straightforward solution. There are a lot of pieces to the happiness puzzle—one of which is food. There's a wealth of scientific studies showing the connection between certain nutrients and mood.

When it comes to food and happiness, there are some foods that help provide momentary happiness (like a thick slice of chocolate cake or a plate of hot cheese fries), and then there are foods that are full of nutrients linked to supporting more long-lasting happiness. According to psychiatrist Daniel Amen, MD, who has written over 40 books, including Change Your Brain, Change Your Life ($13), one of those nutrients is l-theanine.


Experts In This Article
  • Daniel Amen, MD, physician, adult and child psychologist, author, and founder of Amen Clinics, a collection of outpatient healthcare clinics

"L-theanine is an amino acid that has been associated with many beneficial psychotropic effects, most notably reducing anxiety and stress," Dr. Amen says. How exactly does it work and how can you make sure you're consuming enough to have a noticeable difference on your mood? Let's get into it.

The connection between l-theanine and happiness

As Dr. Amen explained, l-theanine is an amino acid, which means it's made up of molecules that combine to form proteins. They're so important that they're often referred to as "the building blocks of life."

"A growing body of research suggests that l-theanine helps promote healthy moods," Dr. Amen says. "For example, a 2017 study published in the journal Acta Neuropsychiatrica on people with major depressive disorder found that l-theanine improves symptoms of depression among other benefits."

How does it do this exactly? Dr. Amen explains that research on animals has shown that l-theanine increases levels of feel-good neurotransmitters, such as serotonin and dopamine. Increasing levels of serotonin and dopamine lead to a mood boost.

At the same time this is happening, Dr. Amen says that l-theanine is also helping reduce feelings of stress and anxiety. " L-theanine enhances gamma-aminobutyric acid (GABA), a neurotransmitter that helps to regulate brain excitability and calms over-firing in the brain," Dr. Amen says. This, he says, leads to feeling calm. "In addition, findings in the journal Nutrients show that l-theanine’s anti-stress properties may lie in dampening the stress hormone cortisol. Another randomized controlled trial showed that taking l-theanine significantly lowered the body’s stress response system," he says.

There's one more way l-theanine and happiness are connected: It can help you sleep. "By reducing the stress and anxiousness that can keep you tossing and turning all night, l-theanine promotes better sleep," Dr. Amen says. "A study published in Journal of Child and Adolescent Psychopharmacology found that l-theanine improved sleep efficiency in children and adolescents with ADHD."

Better sleep, feeling calmer, and helping to raise serotonin and dopamine are all ways l-theanine contributes to a mood boost. Now comes the next major question, where can you find it?

How to get enough l-theanine to actually improve your mood

The best source of l-theanine happens to be found in tea, aka one of the most commonly consumed drinks in the world. Dr. Amen says that while green tea is notoriously known to be a great source of l-theanine, black tea and white tea contain it, too.

What's the difference between the health benefits of green tea and matcha? Watch the video below to find out.

In terms of how much l-theanine you need for it to actually impact your mood, scientific studies point to 200 to 400 milligrams a day being the recommended amount. A typical cup of green tea only has about six milligrams of l-theanine, so if you truly want to get the maximum amount, you may want to consider an l-theanine supplement. But rest assured that even if you are just integrated tea into your daily routine, you are still establishing a habit linked to supporting a mood boost; plenty of scientific studies show that this habit has been linked to happiness.

Sure, a cup of tea isn't going to solve everything and there are many other factors that play into happiness besides l-theanine. But it's such an easy habit to integrate into your life, why not give it a shot? Chill vibes are just a few sips away.

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