Theanine and Caffeine: The Definition of Synergy

Theanine and Caffeine

Theanine and Caffeine are both found naturally in Green Tea where they have long been believed to act synergistically, promoting what can be described as a state of “calm alertness”. Theanine, by itself, has non-sedative relaxation properties, while Caffeine tends to promote alertness and can increase perceived (mental) energy.

Combining Theanine with Caffeine essentially offers the benefits of both compounds, but removes some of the negative side-effects of Caffeine (i.e. jitters, anxiety, etc.). The relationship between Caffeine and Theanine has been the subject of multiple double-blind, placebo controlled studies, all of which support the notion that Caffeine and Theanine are indeed synergistic.


In a 2008 study, published in “Nutritional Neuroscience”, researchers investigated the cognitive effects of a combination of Theanine and Caffeine compared to Caffeine alone on various measures of cognitive performance. Participants received either 50mg of Caffeine or 50mg of Caffeine and 100mg of Theanine before completing various tasks including word recognition, visual image processing, and attention switching.

While Caffeine was able to increase alertness and accuracy during the attention switching tasks, the combination of Caffeine and Theanine was able to improve both performance and speed, while reducing the subjects’ susceptibility to distraction.

Another 2008 study from “Biological Psychology” found that, while 150mg of Caffeine increased alertness and improved (decreased) reaction time, adding 250mg of Theanine further improved reaction time, alertness, and decreased the number of headaches reported from Caffeine.

A 2010 study, also from “Nutritional Sciences”, found that the combination of 97mg of Theanine combined with 40mg Caffeine significantly improved focus and attention on various cognitive tests, compared to placebo.

Another 2010 study, this one published in “Appetite”, noted an improvement in task-switching ability using the same 97mg Theanine/40mg Caffeine combination.


The most common dosing protocol is a 2:1 ratio of Theanine to Caffeine (i.e. 100mg Theanine 50mg Caffeine), though anecdotal evidence indicates that synergy exists with a variety of different proportions. Those who are not particularly sensitive to Caffeine may prefer to invert the standard dosing protocol to 1:2 of Theanine to Caffeine (i.e. 100mg Caffeine 50mg Theanine). A little experimentation is required to find the ideal dose for each individual.


Theanine is extremely safe, either alone or in combination with Caffeine, and has not been shown to cause any adverse effects in animals or humans at varying doses. A 2006 study from “Food and Chemical Toxicology” found no adverse health effects in rats treated with 4000mg/kg daily for 13 weeks. Caffeine consumption, on the other hand, can certainly have negative side effects if too much is taken, so understanding how tolerance/sensitive you are is important. Always start with a low dose and work your way up (not the other way around).


Theanine and Caffeine can be purchased seperately and combined, but Smart Caffeine contains a highly effective 2:1 ratio of Theanine to Caffeine conveniently combined in each capsule. Each capsule contains 100mg of Caffeine, allowing for flexible dosing depending on your personal Caffeine tolerance.


The term “synergy” tends to be overused to the point of falsehood, but the synergy that exists between Theanine and Caffeine is quite real, and is substantiated by an increasingly large body of research. Theanine can be added to your pre-workout supplement to negate some of the negative effects associated with large doses of Caffeine, while still preserving (if not augmenting) the increased focus and perceived energy. Ultimately, if there are two compounds that truly belong together, its these two.

[expand title=”References” tag=”h4″]

  1. Owen, Gail N., et al. “The combined effects of L-theanine and caffeine on cognitive performance and mood.” Nutritional neuroscience 11.4 (2008): 193-198.
  2. Giesbrecht, Timo, et al. “The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness.” Nutritional neuroscience 13.6 (2010): 283-290.
  3. Haskell, Crystal F., et al. “The effects of L-theanine, caffeine and their combination on cognition and mood.” Biological psychology 77.2 (2008): 113-122.
  4. Einöther, Suzanne JL, et al. “L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness.” Appetite 54.2 (2010): 406-409.
    [/expand] exists to educate the supplement community and seperate the science from the hype.

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