Healthy Food & Life: Reduce Anxiety and Brain Fog with L-Theanine
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Reduce Anxiety and Brain Fog with L-Theanine

Fog through tree feels like brain fog

Does brain fog cause you to feel unfocused and unable to concentrate, and nothing seems to help. Coffee works, but only for a short time and can cause anxiety and jitters. L-theanine is a safe supplement you can take that not only reduces brain fog but also reduces anxiety, helping you to focus and concentrate throughout the day.

Brain fog can make doing your job or just getting through the day difficult, to say the least. When we feel brain fog coming on, we all seem to reach for another cup of coffee. But drinking too much coffee has drawbacks including anxiety, jitters, and inhibiting sleep, which can cause the mind to become even more unfocused.

 Why We Get Brain Fog

As you read this article, is your mind wandering. Do you find yourself checking your email, Facebook page, or other websites instead of focusing on what you should be doing? We’ve all experienced brain fog before, and it is frustrating. The symptoms of brain fog can include:

  • Inability to focus on tasks
  • Trouble concentrating
  • Easily distracted
  • A lack of mental energy
  • Foggy and muddled thinking

Some common reasons we get brain fog include:

Brain Fog and Age

As we get older, we might notice brain fog occurring more than it used to, and caffeine helping less than it used to. Brain fog can increase as we age because,

  • Stress levels increase
  • Neurotransmitters GABA or serotonin levels in the brain decrease
  • Glutamate levels increase causing more stress
  • Quality of sleep declines
  • Mood and long term memory decline

These can all contribute to neurodegenerative disorders of the brain as we age. L-theanine can not only reduce brain fog but also protect brain cells from stress-induced cognitive impairments. [1]

drawing of brain

What is L-theanine?

L-theanine is a non-protein amino acid that is primarily found in green tea and in some mushrooms and is classified as a nootropic. A nootropic is a substance that can enhance mental functioning including boost memory, learning, and overall brain function. A Romanian psychologist and chemist Dr. Corneliu Giurgea coined the phrase nootropic, in 1972.

Dr. Giurgea stated that a nootropic should have the following characteristics:

  • Enhance learning and memory
  • Protect the brain and increase natural cognitive processes
  • Should not be toxic
  • Should not stimulate the brain
  • Should not depress the brain


How L-theanine Can Reduce Brain Fog

The beauty of L-theanine is that it creates calm mental energy while enhancing focus, concentration and cognitive ability, while at the same time reducing anxiety and stress. In fact, L-theanine can also promote a good night sleep when it’s time to go to sleep.

There is quite a bit of science behind how L-theanine accomplishes this. The human brain has approximately 86 billion nerve cells or neurons. These brain cells communicate with each other via chemical messengers that are called neurotransmitters.

L-theanine works by boosting the neurotransmitters, GABA, serotonin, and dopamine. These calming neurotransmitters regulate emotions, mood, concentration, alertness, and sleep, as well as appetite, energy, and cognitive skills.

While boosting these calming neurotransmitters, L-theanine reduces the chemical excitatory neurotransmitter - glutamate - that can cause stress and anxiety. L-theanine blocks some of the glutamate’s effects.  

It is believed this is how L-theanine can protect brain cells against stress and age-related neural damage.

In addition, L-theanine promotes wakeful relaxation by stimulating the production of alpha waves in the brain. This creates a state of relaxation and mental alertness that has been compared to how a person feels during meditation. In other words, L-theanine has the ability to create a calm mental focus, and reduce brain fog away without any feelings of sedation.

The reason that L-theanine is able to accomplish this, is because it is able to cross the blood-brain barrier, allowing positive impacts on a variety of the brain’s neurotransmitters and receptors.

My Experiences with L-theanine

Anyone can get brain fog, even if you eat the healthiest diet, exercise and never drink alcohol. Sitting at a computer all day can be mentally tiring enough, but occasionally my mind would lack mental focus, struggling to stay focused and concentrate on my job.

The first day I tried L-theanine, I took a 100 mg capsule first thing in the morning with a cup of coffee. I noticed a quick improvement in my mental focus, concentration and cognitive ability.

For weeks prior, I had been struggling with a stubborn computer problem and read all types of solutions, but I couldn’t figure out the right answer. That first day I took L-theanine, I went back to reading all the same solutions and the solution just came to me, finally.

This could have been a coincidence, but I have noticed many other similar days where answers came to me more quickly, and my mental focus, comprehension, and cognitive abilities seem much better. The brain fog lifted and no more lack of mental focus.

Another benefit was that I no longer felt the need to take a nap after lunch. I was able to stay focused all day and do my job. When it came time to go to sleep, I had no problem falling asleep and stayed asleep through the night.  

How to Take L-theanine

Most like to take L-theanine with a cup of coffee. Coffee is also considered by some as a nootropic because it can keep you alert, and improve memory. But it can also cause nervousness and anxiety, which can lead you to become easily distracted. And then there is the caffeine crash later in the day, which in itself can lead to brain fog.

L-theanine takes the edge off coffee and counteracts these negative aspects as it relaxes the mind, making it an excellent combination. It is suggested that a 2:1 ratio (L-theanine to caffeine) is optimal.

The amount of caffeine in a cup of coffee can vary depending on how it is brewed and the roast of the coffee. A light roast will have more caffeine than a dark roast will. Typically, a brewed cup of coffee will have about 95 mg of caffeine. So using this ratio, a person would take 200 mg of L-theanine with a cup of coffee. I usually drink one cup of dark roast coffee and take one L-theanine capsule in the morning.

But coffee is not necessary to get the full benefits of L-theanine, as it works just fine with tea, Yerba mate or even without coffee. I have taken L-theanine with tea or decaffeinated coffee and the L-theanine worked great, sometimes even better actually, especially for those that find coffee too caffeinated.

L-theanine is usually sold in doses of between 100 mg and 200 mg. L-theanine works fast, usually, within 30 to 40 minutes, you will be able to feel the brain fog lifting with increased mental focus. 

My favorite brands are Doctor’s Best L-theanine with Suntheanine 150 mg and Enzymatic Therapy L-theanine Suntheanine 100 mg. Suntheanine is a patented pure form of L-theanine that has been extracted from green tea.

More Health Benefits of L-theanine

In addition to creating relaxed alertness and reducing brain fog, L-theanine also has the following health benefits:

  • L-theanine reduces anxiety and also attenuates blood pressure increase in adults that were susceptible to high-stress responses. [2]
  • Another study found that L-theanine improved sleep quality in boys with attention deficit hyperactive disorder (ADHD). [3]
  • One study found that L-theanine can reduce anxiety in patients with schizophrenia. [4]
  • L-theanine can also reduce brain damage caused by a stroke if given up to 12-24 hours after a stroke. [5]

Since green tea is known to have many health benefits, scientists continue to study which of these health benefits can be attributed to the L-theanine in the green tea.


L-theanine is a great way to reduce brain fog and increase mental focus, concentration, and cognitive abilities. Another benefit is that it won’t inhibit sleep like caffeine does; in fact, it helps you get a good night sleep.

The dosage is usually 100-400 mg, and you most likely do not need it each day. You should never exceed 1,200 mg per day. You should talk to your doctor first if you are taking any medications as L-theanine can also lower blood pressure. [6] 

In addition to taking L-theanine for brain health, you can also help your brain by adding the proper foods and nutrients to your diet. Certain foods have nutrients like phytochemicals and omega-3 fatty acids that can protect your brain against aging and memory loss. 

About the Author

Sam Montana is a certified Food Over Medicine instructor from the Wellness Forum Health Center and certified in optimal nutrition from the Harvard T.H. Chan School of Public Health.

© 2019 Sam Montana/Healthy Food and Life


[1] PubMed: Protective effect of l-theanine on chronic restraint stress-induced cognitive impairments in mice.
[2] Journal of Physiological Anthropology, 2012: Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses.
[3] Pharmacology, Biochemistry, and Behavior: The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD).
[4] Journal of Clinical Psychiatry: L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder.
[5] PubMed
[6] RxList
Reduce Brain Fog with L-Theanine


  1. Excellent article. More and more people seem to be suffering from brain fog and similar issues because of the lack of complete nutrition in our diets.

    I write extensively about nutrition and it's clear that the classic vitamins and minerals we're used to hearing about only tell one part of the nutrition story. There are many different amino acids, phytonutrients, micronutrients, and other compounds that are rarely talked about but are just as important for maintaining a healthy body.

    Helpful piece!

    1. Hi Matthew. I was pleasantly surprised at how well L-theanine worked for me.

      What I liked the best was my attention wasn't all over the place. Like moving between open tabs instead of working on what I was supposed to. The focused attention was great.

  2. L-Theanine is quite useful and an underratted micro nutrient. Mark Hymnann speaks volumes about it.

    1. I will look him up and read what he says. I really do like L-theanine and the way it creates mental focus and calming at the same time.

  3. Very helpful post thanks for sharing it

  4. Wow! Who knew...
    Thanks you for sharing!

  5. Interesting article. I suffered from chemo induced brain fog. While I am not a fan of taking supplements... I would rather get my nutrition from foods... this could be helpful.