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Supplement Facts & Directions

Supplement Facts

Serving Size: 500 milligrams
Servings Per Container: Varies
Amount Per Serving % Daily Value*
L-Theanine 500mg

* Percent Daily Values are based on a 2,000 calorie diet.
† Daily Value Not Established
‡ These supplement facts may vary from the product you receive.    Please call for exact numbers.

Other Ingredients: None


Free of:  Sugar, Soy, Dairy, Yeast, Gluten & Additives.

Directions:  As a dietary supplement, take 500 mg (3/16 tsp) up to three times daily, or as directed by a physician. Accurate gram weight scale recommended.

Warning: If you are pregnant, nursing, taking any medications or have any medical condition consult your physician before use. DO NOT use if you are taking blood pressure medication. Keep out of reach of children.

Product Details

What is L-Theanine?

L-Theanine is an amino acid that shares structural similarities with glutamine and glutamate, which are also amino acids. Theanine can boost the supply of several amino acids by hydrolyzing them into glutamate. The body then uses glutamate to synthesize glutamine as well as GABA.

L-Theanine is one of the primary active ingredients found in teas produced from the Camellia sinensis species of plants. Countless individuals swear by the health and relaxation benefits of drinking green tea, many of which are due to the drink’s high theanine content.

However, most green teas sold in stores contain less than 10 milligrams of L-theanine per serving. It’s almost impossible to drink enough green tea to feel theanine’s effects. L-theanine powder offers a more direct and consistent approach to experience the benefits of l-theanine.

Potential Theanine Benefits

L-Theanine crosses the blood-brain barrier with ease. It takes less than an hour to reach the brain after taking l-theanine powder, and theanine levels remain elevated for up to five hours.

L-Theanine and Relaxation

L-Theanine owes much of its popularity to its ability to promote relaxation without sedation or drowsiness. L-Theanine dramatically increases alpha brain wave activity, which enhances mental alertness and focus while in a relaxed state. Alpha brain waves also boost creativity and creative thinking. Secondary to its relaxation properties, l-theanine powder may provide some stress relief as well. In animal studies, theanine reduced circulating corticosterone (stress hormone) while at rest and following stress tests.


L-Theanine for Focus

Theanine powder is a popular nootropic due to its potential to improve memory and enhance focus. It also reduces the perception of stress and stress-induced memory impairment. Theanine may enhance working memory and executive function. While theanine powder has nootropic properties, pairing it with caffeine greatly enhances these effects.

l-Theanine and Caffeine

L-Theanine and caffeine synergize to improve attention and accuracy. Caffeine reduces the perception of fatigue while improving reaction times and rapid visual information processing. The addition of theanine sustains those benefits while further improving reaction times, alertness, attention, and the ability to switch between tasks. Theanine also helps attenuate some of caffeine’s side effects, such as headaches and feeling jittery. Theanine may also provide neuroprotective benefits by reducing oxidative damage to neuronal cells.

L-Theanine and Sleep

L-Theanine powder doesn’t cause drowsiness like traditional sleep supplements. However, studies show that theanine may shorten the amount of time it takes to fall asleep and reduce the number of sleep disruptions. Theanine may also improve mental clarity by improving sleep quality. L-Theanine also synergizes with GABA to increase sleep quality and duration.

L-Theanine Side Effects

Most individuals tolerate l-theanine well. L-Theanine powder provides consistent and more reliable results than drinking green tea. Consuming large amounts of green tea can also cause nausea and irritability due to the caffeine content.

Vegan Friendly

L-Theanine powder is derived from tea plants, and it is vegetarian and vegan friendly.

Purity of L-Theanine Powder

L-Theanine powder contains no additives, fillers, or anti-caking agents. It arrives in a resealable bag. Keep l-theanine powder in a cool, dark, and dry place.

How to Take L-Theanine Powder

Theanine powder dissolves quickly in water. It has a mild taste and activates umami taste receptors. Theanine mixes well with water but infusing theanine with hot tea or juice provides a subtle savory flavor.


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  3. https://www.ncbi.nlm.nih.gov/pubmed/4397636
  4. https://www.ncbi.nlm.nih.gov/pubmed/10361674
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  15. https://www.ncbi.nlm.nih.gov/pubmed/21739364
  16. https://www.ncbi.nlm.nih.gov/pubmed/23458739
  17. https://www.ncbi.nlm.nih.gov/pubmed/23395732
  18. https://www.ncbi.nlm.nih.gov/pubmed/16930802
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Further Reading

Tested by Accredited 3rd Party Labs

PureBulk's supplements are tested by accredited third party labs in the USA to ensure their identity, purity and potency. To receive a copy of these test results or any other PureBulk supplement please fill out the COA request form found here.

*NOTE: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.