L-Theanine Cures

| Modified on Nov 11, 2021

In addition to relaxation, research suggests that L-theanine may have application in the following:

  • diminishing symptoms of PMS,
  • improving learning performance,
  • heightening mental acuity - neurotransmitter,
  • promoting concentration,
  • acting antagonistically against the paralysis induced by caffeine,
  • supporting the immune system,
  • lowering blood pressure,
  • increasing formation of the inhibitory neurotransmitter GABA, and
  • increasing brain dopamine levels among other positive benefits with no known downside.

L-theanine also adds unami (a brothy or savory) taste when added to water, coffee, tea, etc. Decreases bitter taste when added to coffee, tea, and other beverages and foods. Takes effect within 30 minutes after consumption. No known cautions or drug interactions

Stress and Anxiety

Stress and anxiety are debilitating conditions that can shorten life span while lessening performance, well being, and the enjoyment of life. Stress can impair the ability to perform mentally. It may result in reactions to situations that cause enhanced frustration, hostility or even injury. Stress slowly destroys the immune system, lowering resistance to disease and thus allowing degenerative and opportunistic diseases to occur. Stress is a cause of depression. The entire population is subjected to stress. In a 1998 survey, nearly 65 percent of the adult population indicated that they were under great stress. More than 23 million Americans suffer from anxiety illness.


Studies in cooperation with Taiyo Kagaku Co., The University of Shizuoka, and The Family Planning Institute of Japan have shown that women taking 200 mg L-theanine daily have lower incidence of PMS symptoms. These symptoms include physical, mental, and social symptoms. Overall, a significant alleviation of PMS symptoms by L-theanine was observed.

Brain Chemical May Thwart Ravages of Aging Study

L-theanine appears to have a role in the formation of the inhibitory neurotransmitter Gamma Amino Butyric Acid (GABA). GABA blocks release of the neurotransmitters dopamine and serotonin, playing a key role in the relaxation effect.
By Keith Mulvihill

[Info about GABA]

SOURCE: Science 2003;300:812-815.

NEW YORK (Reuters Health) - A shot of a brain chemical called GABA essentially turned back the clocks in the brains of older monkeys, whose brain function briefly operated at levels normally seen in monkeys less than half their age.

The finding may one day help scientists reverse similar age-related deterioration in the brains of people, according to the report published Friday in the journal Science.

GABA, or gamma-aminobutyric acid, is a messenger chemical that is essential for optimizing how brain cells transmit messages to each other and acts to put a damper on unwanted brain signaling activity, explained the study's lead author Dr. Audie G. Leventhal at the University of Utah School of Medicine in Salt Lake City.

Although GABA's age-related decline has not been documented in humans, a host of studies in mammals, including other primates, suggests that a similar process is at work in people, explained Leventhal.

L-theanine Documented Safety

L-theanine is considered to be safe based on its historical use as a component of tea and on favorable toxicology studies. Tea is the most consumed beverage worldwide after water, and has been consumed for thousands of years by billions of people. It is estimated that a heavy tea drinker (6-8 cups daily) will consume between 200 to 400 mg of L-theanine daily.


100 to 200 mg 1 to 3 times daily or as needed depending on stress and anxiety levels. Based on the results of clinical studies, it has been established that L-theanine is effective in single dosages in the range of 50-200 mg. It is suggested that subjects with higher levels of anxiety take a dose at the higher end of the effective range (100 - 200 mg) for best results.


3 User Reviews
5 star (2) 

Posted by John (CA) on 11/10/2021

I just want to caution those who have never taken L-Theanine before. Many people have experienced greater anxiety than they were experiencing before. Sadly ironic, most of them were seeking something to relieve their acute anxiety and high blood pressure. I had taken it to relieve my high BP and at first it was amazing. I was so alert and calm at the same time. I checked my BP with my home unit and it was indeed much lower. I let the dose I took wear off and I was subjected to heart palpitations and anxiety big time. It was as though there was some sort of "snap-back" effect where the symptoms were suppressed but once released came back amplified. If you wish to read over 150 personal reviews (both good and bad) try this website.


Good luck. I hope you find relief to your problems.

Posted by Jackie (Grand Rapids, Minn) on 06/24/2010

we, my cousin and i, take care of our parents at home, my mother is 101 and aunt is 103. aunt has short term memory loss and mild dementia, gets angry and anxious. but does not do well on any prescription antianxiety meds or antidepressants. suntheanine or l-theanine is wonderful for her. she takes 100mg morning and evening. keeps her calm or at least calmer without risking falls and we have more peace in the house. it has a mild taste so is easily disguised in her food or on toast. she had a bad reaction to zoloft in the past, sleeping all the time, had dehydration and a bad fall and got overly stimulated with the exelon patch. this is a wonderful supplement

Replied by Dee
(Porter, Tx, Usa)

For the past month, I have been taking a supplement that contains L-Theanine in addition to 3 other natural ingredients. I had not heard of L-Theanine prior to taking this supplement. Before starting it, my stomach was always in knots and I had no energy or focus. This was all due to external stress factors that were beyond my control. I feel like I have done a complete 180. The stress factors are still present and my emotions are my own, but I respond to them more rationally. I also have more motivation to complete daily tasks. During the past month, I have experienced PMS, but the irritability was very mild compared to previous months. I don't know the exact dosage of the L-Theanine specifically. Two capsules contain 350 mg of the 4-ingredient formula. I take two capsules after breakfast daily.

Replied by Janice
(Coloma, Mi)

What are the other ingredients in the formula?

Child Doses of L-Theanine

1 User Review
1 star (1) 

Posted by Renee (Elizabeth, Pennsylvania) on 12/23/2009

i want to know how much of l-theanine would i give my twelve year old down syndrome child? he weighs 70 lbs. are there any vitamins or minerals that do not mix with l-theanine? please e-mail me back as soon as possible thanks alot.

Replied by Joyce
(Joelton, Tn)
495 posts

Hello to the one wanting to know how much l-theanine to give her 70 lb. Down' syndrom child,

Using Dr. Schultz's preferred method of body weight to figure dosage for children and pets:

Knowing that adult dosage is figured for body weight of l50 lbs. you can readily see that a 70 lb. child would be slightly less than 1/2 the adult dosage. If he weighed 75 lbs. it would be exactly 1/2 the adult dosage.

Replied by Jennifer


I understand that a person with Down Syndrome has overactive GABA receptor sites, therefore you would be better off giving Gingko to decrease the GABA. You may want to check it out before continuing.

L-Theanine Reader Feedback

2 User Reviews
5 star (2) 

Posted by Hermano (Lisbon, Portugal) on 10/16/2006

L-THEANINE is the best for a mild anxiety. also i tried before playing golf and the results are a four or five better score.this site of yours is the most informative and serious that i have found. thank you.

L-Theanine Reader Feedback
Posted by Laura (Seattle, WA)

I recently inquired about various supplements for anxiety at Whole Foods Market. Besides 5-HTP, the specialist told me that another popular amino acid for anxiety and stress was L-Theanine. I tried it and have to say, it had an immediate effect! Within about 15 minutes I was feeling very calm. I also slept incredibly deeply for 8 hours, not waking once. I look forward to seeing if it works for PMS and will report back to you if it works! They suggest on the bottle to take one every 4 hours but frankly, 1 a day works just fine for me!

Replied by Mom2
(Chicago, Illinois)

I was wondering do you feel the effect after taking it once or do you have to wait and build it up in your body for a period of time?

Replied by Jsthiel
(Blaine, Mn)

Does anyone know if this is compatable with RHODIOLA?