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L-Theanine | Benefits, Sources & Dosing

What Is L-Theanine?


The year is 3,000 B.C.E, you are in China, and while the rest of the world is still wondering why the big yellow ball in the sky won’t answer their prayers, you are drinking a warm chamomile tea to help yourself think more clearly and heal your various ailments. Skip ahead 4,000 years and the Japanese culture is drinking tea simply for pleasure, involving its own ceremony which includes a unique tea house to serve it in. Western culture wouldn’t catch onto the amazing benefits (and pleasure) of tea for hundreds of years…

Derived from drying leaves which bud on the tree Camellia Sinensis, many types of tea exist including chamomile, black, green, and oolong, and besides water, they are the most consumed beverage in the world. There are various compounds in tea which have positive benefits on our health. Flavonoids such as Catechins and Flavonols are both antioxidants which can fight free radicals, preventing many types of diseases, including cancer.

Caffeine is probably the most ubiquitously known compound in tea, giving many of us the kick in the pants we need to start our day with energy. The only issue with caffeine coming from sources like coffee and energy drinks include becoming jittery, a crash to follow soon after prompting the need for another 200mg dose, and many sleepless nights. Caffeine sticks around in our body for 10 hours after consumed which most of us (myself included) forget when we take that pre-workout at eight in the evening to get through our lifting session after work, leaving us awake in bed for hours.

L theanine green tea

The last compound, an amino acid, present in tea which actually nullifies the negative benefits of caffeine, while enhancing the positives is L-Theanine. This relatively new amino acid is found almost exclusively in tea (and a type of mushroom called Boletus Badius), and can do wonders for anybody looking to improve their mood, clear their head, lower their blood pressure/cholesterol, and even prevent symptoms of certain western diseases.

L-Theanine Benefits

Discovered in 1949, this amino acid is molecularly similar to L-Tryptophan and is extensively researched in Japan. This research leads to dozens of discoveries about how the brains hormones and bodily functions can be influenced by L-Theanine. One cup of tea supplies about 25 to 50 milligrams of L-Theanine, which isn’t enough to cause a major difference in the normal individual. Most research shows around 250 to 500 milligrams will give the most benefit (it is available in bulk powder form as well to help get such a large amount). Any extra supplementation will simply be excreted through your urine as this amino acid is water soluble, also meaning it’s almost impossible to overdose or has serious adverse side effects from L-Theanine at any dose.

L TheanineMost people experience a much calmer and relaxed state while still being able to think clearly when supplementing with L-Theanine. This comes from the increased alpha brain waves it enhances (which are the brain waves that occur while you are awake). With the ability to cross the blood-brain barrier, this amino acid can prevent damage to brain cells and stimulate the growth of new brain cells, leading researchers to believe this supplement can potentially help individuals suffering from diseases such as Parkinson’s and Alzheimer’s.

A benefit that is usually underappreciated when it comes to L-Theanine includes its antioxidant properties. When the tea is mentioned as an antioxidant most think of the compound epigallocatechin gallate or ECGC which is a potent antioxidant, but doesn’t have some of the antioxidant properties shown in L-Theanine. Besides preventing the growth of cancerous tumor cells in the pancreas, skin, breast, stomach, ovaries, oesophagus, lungs and prostate2, the benefits have been known to include preventing the oxidation of LDL cholesterol (or the “bad” cholesterol).

Who’s L-Theanine For?

The most popular use of L-Theanine come from individuals wanting to improve their mood and mental alertness. As previously mentioned this effect works very well when you combine L-Theanine and caffeine in a 2:1 or sometimes 4:1 ratio. Best described as a Yin and Yang type synergy, these two compounds combined to give the alertness of caffeine, while the L-Theanine relaxes any jitters some get and curb the fatigue that follows when your body finishes processing all the caffeine. Researchers of a study published in the December 2010 issue of the journal “Nutritional Neuroscience” found that a combination of 97 milligrams of L-Theanine and 40 milligrams of caffeine improved attention, focus and accuracy during a demanding mental exercise1.

Most surprisingly researchers of a tissue culture study published in the July 2012 issue of the “Journal of Nutritional Biochemistry” found that L-Theanine improves cardiovascular health by promoting the production of nitric oxide (a compound that causes blood vessel dilation in the linings of arteries). In this way, L-Theanine may reduce blood pressure and decrease risk for cardiovascular disease1. The increase of nitric oxide may also have a minor benefit when exercising (giving a better “pump” and less muscle fatigue as a result), perhaps not to the extent of L-Arginine or Citrulline Malate though, which are both potent nitric oxide boosters, but will benefit the user however limited.

gaining muscle mass

Take Home Message

This amino acid is by far the most underrated in the supplement industry, with its numerous health benefits and lack of side effects it can and should be used by everybody looking to improve their overall health and wellness! Whether it be for the cognitive focus when studying, for its mind and body relaxation function to help you fall asleep/offset the side effects of caffeine, or for its antioxidant properties to help lower potentially cancerous oxidative damage to the body.

To get the maximal benefits from L-Theanine, two to three cups of green tea (black has less of the amino acid) a day can supply you with about the recommended 200 mg. But for those who need more and don’t drink that much tea or don’t like tea can buy L-Theanine as a bulk powder, which can be added to any kind of liquid or food. This supplement is high on my list of must-haves and should be on yours too! Thank you for taking the time to learn a little bit and always remember, smarter not harder when it comes to your health and fitness!


Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

1 Roizman, Tracy. “What Are the Benefits of Using L Theanine?” Healthy Eating. N.p., n.d.             Web. 02 Aug. 2016.

2 Appleby, Maia. “Is Green Tea Good for You & How Much Can You Drink Daily?” Healthy            Eating. N.p., n.d. Web. 02 Aug. 2016.

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Billy Galipeault

Billy Galipeault

Writer and expert

Billy is passionate about all things fitness and nutrition, with an emphasis on muscle and strength building. He's currently serving active duty in the air force, while building his body muscle by muscle in his free time.

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