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What is L-Theanine?

L-Theanine is an amino acid that is found in a variety of plant and mushroom species, and is particularly abundant in green tea. L-Theanine is commonly referred to as simply, Theanine, not to be confused with the enantiomer, D-Theanine. L-Theanine possesses a unique savory, umami flavor profile and is often used to reduce the bitterness in some foods. 


L-Theanine is commonly taken for its calming effect on mood & sleep. It supports brain function and may aid alertness, focus, cognition, and memory. L-Theanine fortifies immune function and supports the heart & cardiovascular system. 

  • Promotes healthy sleep
  • Supports brain function
  • Contributes to alertness & focus
  • Aids cognition & memory
  • Fortifies immune function
  • Assists cardiovascular & heart health

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.

Supplement Facts
Serving size: 250 milligrams
Serving per container: *
Amount Per Serving % Daily Value**
L-Theanine 250mg *
* Daily Value not established.
** Based on 2,000 calorie diet


 Sugar, soy, dairy, yeast, gluten, corn and additives.

 As a dietary supplement, take 100mg to 250mg one to three times daily.


This supplement is considered pharmaceutical grade and contains no fillers of any kind. It is totally vegan and is derived from the tea (Camellia sinesis) plant.


Note: This supplement may lower blood pressure. Those who are currently taking blood pressure medication or have a history of related issues should first discuss use with a trusted health care professional. Take with caution.

Always consult a physician before taking any dietary supplement.

L-Theanine should not be taken by anyone that has ever been diagnosed with liver or kidney disease or by women who are nursing or pregnant. While this supplement has no side effects at recommended servings, it may function as a sedative if serving size is not adhered to.


This product is soluble in water and has a broth-like flavor, similar to green tea. Since it is an amino acid, it should be taken along with other amino acids to avoid any deficiency. It should be stored in an area free from light, heat and moisture.


There is no guarantee of specific results and results can vary.

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.

California residents: Click Here for Proposition 65 warning.

Customer Reviews

4.8 Based on 1979 Reviews
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Brian M.
United States United States

Calming L theanine

Always amazing. Take this in place of dangerous pharmecuticals. Like I do. A little bit of a nootropic as well

Doug W.
United States United States

Good Quality

As far as I can tell, it is just as it should be.

Hunter C.
United States United States

Left at door and was taken

Never got the chance to try it because it was left at my apartment door and somebody stole it.


Hello, We've looked into your order. It appears that it was left at your leasing office. Please check with them and confirm.

Bob H.
Canada Canada

Awesome! It works well.

This product helps peaceful sleep.

Guido A.
United States United States

Synergy of L-theanine and GABA

In the article "GABA and l-theanine mixture decreases sleep latency and improves NREM sleep" at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6366437/ the authors found that GABA and L-theanine in the ratio 5:1 is more effective than either alone, and more effective than both at other ratios: "The effects of the best sleep-promoting GABA/l-theanine dose combination (100/20 mg/kg) were compared to the changes in sleep latency and duration induced by the single administration of GABA or l-theanine ... . The combined use of GABA/l-theanine (100/20 mg/kg) showed a decrease in sleep latency (20.7% and 14.9%, respectively) and an increase in sleep duration (87.3% and 26.8%, respectively) compared to a single administration of GABA (100 mg/kg) or theanine (20 mg/kg). The combined use of GABA/l-theanine showed synergy effects on sleep latency and sleep duration time." The authors measured sleep duration and latency for the following four proportions of GABA/L-theanine, in mg / kg. 80/20 80/30 100/20 100/30 The maximum sleep duration and shortest sleep latency was found at the 100/20 = 5/1 ratio. Therefore, since for insomnia, a typically used dose range of L-theanine is 100 mg - 250 mg, it follows that the optimal GABA dose ranges from 500 mg to 1250 mg. I found the above article after having ordered 100 g of GABA and 100 g of L-theanine; the correct quantities should have been, per the optimal 5/1 ratio, 500 g GABA and 100 g L-theanine. I give this product a temporary 5-star, based only on the above research. (In the past, I have already used theanine, but not GABA). My experience with theanine alone is positive, but not completely satisfactory.) I will try soon 500 mg GABA and 100 mg L-theanine per insomnia, increasing the dose, if necessary, to 1000 mg GABA - 200 mg L-theanine; and will report accordingly in less than four weeks.

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