Green tea - theanine and caffeine

L-Theanine – a perfect complement for caffeine

Caffeine is the most popular stimulant in the world. Every day, it brightens and sharpens the minds of millions of people. Unfortunately, some do not tolerate it best, especially at higher doses. If you are one of these people, then you are in the right place! We know the way to get rid of the negative effects of caffeine, and at the same time to slightly boost its action.

Of course, we are talking about theanine. It is an amino acid that is one of the most popular nootropic agents. It occurs mainly in green tea, so it is inherently similar to caffeine. L-Theanine is used mainly to reduce stress and nervous tension, and also to calm down, relax, and sometimes to make it easier to fall asleep. Despite calming activity, many people report reduction of agitation, but without an excessive sedation, which is already a very big advantage of this agent.

How does l-theanine combined with caffeine work?

At first you can have mixed feelings – why combine the stimulant with a silencing agent? Is not that contradictory? Well, in this particular case, it turns out that no. Not only is it not contradictory, but it is also a very good combination. Theanine seems to be quite a ‘smart’ agent because it adapts to a certain extent to the situation. In examinations using electroencephalogram (EEG), it was observed that the increase in the intensity of alpha waves in the brain is the stronger the higher the baseline level of anxiety in a given person is. However, at times when a highly focused attention is required, alpha waves can even reduce their intensity. Alpha waves have frequency which is associated mainly with the state of meditation and deep relaxation.

In order not to rely only on vain declarations, let’s take a look at what the scientists have to say.

A study in which participants were divided into 4 groups was conducted:

  • placebo
  • 250 mg of caffeine
  • 150 mg l-theanine
  • 250 mg of caffeine + 150 mg of l-theanine

The agents were ‘smuggled’ in a rather attractive form of the Peach Lite Lipton Ice Tea drinks instead of standard capsules. Each group was subjected to appropriate cognitive tests. The division into such groups allowed to properly analyze which effects were specific for one of the substances used, and which resulted from the synergy of action and were unique for their combination.

Each participant of the study was tested 4 times (+ one control visit), and the intervals of seven days were maintained between each trial. On the day of the trial, tests were carried out up to 3 times. First, half an hour before consuming a drink to determine the baseline cognitive ability that day. Subsequent tests were carried out half an hour after the consumption, and the last after the next hour, that was 90 minutes after drinking the drink.

As you can guess, in the majority of measured parameters the best results were noted after the consumption of the combination of caffeine and theanine. The main effects were the improvement of well-being, increase in energy and reduction of perceptible fatigue. From the parameters indicating cognitive functions, the combination gave the best results in: accuracy of verifying sentences and fast processing of visual information, speed of word recognition and the time of simple reactions. However, not to present superlatives alone, there were two parameters in which caffeine alone gave a slightly better result. The first is a test in which a participant was counting down from one hundred by sevens, which is called the Serial Sevens test. The second parameter is the ability to reduce headache, here also caffeine alone gave a slightly better effect.

So it is obvious that the combination of caffeine and theanine is one of the most popular and most praised nootropic stacks for a reason. The effects are fast, clear and safe. What more could we want?!


  • Kobayashi, K. et. al. „Effects of L-theanine on the release of a-brain waves in human volunteers.” 1998. Nippon Nogeikagaku Kaishi 72, 153–157.
  • Crystal F. Haskell et. al. “The effects of L-theanine, caffeine and their combination on cognition and mood” Biological Psychology 77 (2008) 113–122 .

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