L-Theanine: An Ingredient with Buzz

An overhead shot at a slight angle reveals two tea cups of green and black tea on the bottom right of the composition inwards to center. Cinnamon sticks and two unused tea bags are nearby. Tea leaves are visible through the tea at the bottom of the teacups, enforcing the natural loose leaf products. The teacups are white with a repeating delicate patterns of gold around the rim.

L-Theanine (or just theanine for short) is an analogue of common amino acids L-glutamine and L-glutamate. This compound is primarily found in plants and fungi, and was first discovered in green tea in 1949[1].  Theanine is said to bring an umami or savory flavor to green teas. Theanine is substantially present in black, white, and green teas[2], but deliberately shading the tea leaves (such as in the production of matcha) can increase the amount of theanine present.  

When consumed, theanine has many wonderful benefits. One of these benefits is better mental focus. In a 2012 study[3], researchers found that participants who took 100 mg of theanine made fewer mistakes in an attention test than those who took a placebo. When combined with 50 mg of caffeine, their focus improved further. This corresponds to additional research that suggests theanine can help increase or improve cognitive function, especially when combined with caffeine[4]. Additional benefits include improved relaxation and sleep[5], and boosting the immune system. However, further research is needed to truly understand the effects of theanine on the human body. When consuming theanine, reports indicate that it is likely safe in doses of 200-250 mg all the way up to a maximum safe dose of 1200 mg daily. 

Theanine is often referred to as a nootropic, which is a wide range of supplements that are said to help improve cognitive function[6]. Caffeine is the most commonly seen and consumed of these compounds, which is often come in the form of coffee. The combination of the bitterness of the coffee and the taste of theanine can be challenging to overcome and TastesNatural’s bitter blocker for food and beverage as well as our flavor enhancers and TruSugr™ sugar substitute are able to help offset those negative tastes. 


  1. “How Gyokuro Is Processed: Ippodo.” How Gyokuro Is Processed | IPPODO, https://web.archive.org/web/20180425233636/http://www.ippodo-tea.co.jp/en/tea/gyokuro_03.html. 
  2. Finger, Andreas, et al. “Chromatography of Tea Constituents.” Journal of Chromatography A, Elsevier, 16 Nov. 2001, https://www.sciencedirect.com/science/article/abs/pii/002196739285685M?via%3Dihub. 
  3. Foxe JJ;Morie KP;Laud PJ;Rowson MJ;de Bruin EA;Kelly SP; “Assessing the Effects of Caffeine and Theanine on the Maintenance of Vigilance during a Sustained Attention Task.” Neuropharmacology, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/22326943/. 
  4. Williams, Jackson, et al. “L-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion.” MDPI, Multidisciplinary Digital Publishing Institute, 30 May 2016, https://www.mdpi.com/2306-5710/2/2/13/htm. 
  5. Sarris J;Byrne GJ;Cribb L;Oliver G;Murphy J;Macdonald P;Nazareth S;Karamacoska D;Galea S;Short A;Ee C;Birling Y;Menon R;Ng CH; “L-Theanine in the Adjunctive Treatment of Generalized Anxiety Disorder: A Double-Blind, Randomised, Placebo-Controlled Trial.” Journal of Psychiatric Research, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/30580081/.
  6. PMC, Europe. Europe PMC, https://europepmc.org/article/med/6538101.