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  • Gluten free

  • Vegan

  • Non-GMO

  • Vegetarian

  • Gluten Free

l-Theanine is a unique amino acid blend that helps promote relaxation without causing drowsiness. I-Theanine may also ease occasional nervous tension and irritability.*

  • Promotes relaxation*
  • Helps moderate occasional stress*
  • Made with hypoallergenic, vegan ingredients

Green tea has been recognized for centuries as having relaxant properties. l-Theanine, a unique amino acid derived from tea, provides the characteristic taste of green tea. l-Theanine has also been discovered as the biologically active constituent of green tea responsible for promoting relaxation. In a preliminary non-clinical study, an l-theanine solution enhanced alpha wave production in the occipital and parietal regions of the brains of volunteers. These observed patterns are considered to be an index of relaxation. Furthermore, it did so rapidly and without causing drowsiness. In two additional studies, alpha waves were also shown to be detectable soon after l-theanine administration. Theanine is also useful for supporting healthy cellular function. Preliminary research suggests that l-theanine may be helpful for premenstrual support including healthy mood. Furthermore, theanine has been reported to moderate the effects of caffeine on the central nervous system. l-Theanines safety is supported in studies and by its long history of safe consumption in tea. Pure Encapsulations l-Theanine is Suntheanine®, the brand which has been used in scientific studies.*



Suggested Use:
As a dietary supplement, children ages 8-18, take 1 capsule, 1-2 times daily, between meals. Adults, take 2 capsules, 1-3 times daily, between meals. 


Serving Size: 2 Capsules

Amount Per Serving
L-Theanine ... 400mg

Other Ingredients: Hypoallergenic plant fiber (cellulose), vegetarian capsule (cellulose, water).


If pregnant or lactating, consult your physician before taking this product. Higher doses in some people may cause drowsiness; however lower doses are not associated with this effect.

Keep out of the reach of children.

Why is this a top pick for L-theanine?

This product has been chosen as a Top Pick by Fullscript based on factors like quality, ingredients, value, and availability. Your provider’s recommendation always comes first.

This product was selected based on the factors below: Delivers 100 mg of clinically researched Suntheanine® per capsule, a bioactive amino acid derived from green tea that supports relaxation without drowsiness and helps moderate caffeine’s effects. This vegan-sourced, hypoallergenic formula is non-GMO and free from gluten, dairy, soy, artificial colors, sweeteners, unnecessary binders, fillers, and preservatives. Manufactured in a cGMP facility, each lot undergoes independent third-party testing for purity and potency.*

Learn more about our process

About enhanced testing

Every product on Fullscript meets our high quality standards – but we don’t stop there. Enhanced Testing means select products are pulled directly from Fullscript’s shelves and tested by independent labs, so what’s on the label matches what’s in the product.

Learn more about the testing methods

Top pick

Enhanced testing

L-Theanine, 400 mg

Pure Encapsulations

$65.99

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