Stacking nootropics has become very common for individuals trying to find compounds and supplements that can work great in synergy with one another. Caffeine and L-Theanine just happen to be one of those ‘perfect’ combinations in the chase of the perfect nootropic stack. Caffeine and L-Theanine is also a great choice for beginner nootropic user as it is very subtle yet a great way to drive focus and cognition during your busy day, either at work or while studying. We decided to have look at this combination and see what exactly one can benefit from combining them.  

Caffeine At A Glance

As we all know, caffeine is the key ingredient in coffee and tea. Caffeine is mostly known due to its effects on increasing energy when used, yet the way it goes about this is not all to clear to most. Caffeine’s main function involves its effects of adenosine in the body, acting as an antagonist to adenosine. Adenosine contributes to feelings such as drowsiness, relaxed state and a general feeling of being calm when triggering its receptors in your brain, preventing your brain from being “too excited”.

Adenosine has four receptor subtypes namely - A 1, A2A, A2B, and A3, which caffeine is an antagonist of all four. Caffeine seems to have the highest affinity for antagonising the A2A receptor, being the primary mechanism for caffeine's wakefulness-promoting effects. This receptor also plays an important role in regulating glutamate and dopamine in the brain. This makes A2A a crucial target for regulating sleep, motivation, pain, and physical performance.
Adenosine is mimicked by caffeine, however, it acts in reverse to prevent adenosine from reaching its targeted receptors. The result is a feeling of wakefulness including alertness, both mentally and physical which most coffee drinkers can attest to. Hindering adenosine may likewise influence the frameworks associated with adrenaline, dopamine, serotonin, and acetylcholine, which adds to a significant number of caffeine's potential nootropic benefits. A few examinations demonstrate that caffeine may likewise improve memory, enhance focus, and advance general clarity and cognition.

Caffeine Metabolized

Caffeine also has a host of other benefits from compounds released during its metabolization process. These metabolites are commonly known as Paraxanthine, Theobromine and Theophylline.

Paraxanthine is not naturally occurring in any plant and is only found as a metabolite.  More than 80% of any caffeine dose is metabolized as paraxanthine. Paraxanthine has equal potency to that of caffeine with a host of its own benefits. Paraxanthine acts as a non-selective phosphodiesterase inhibitor, increasing cAMP levels, activates protein kinase A, and also inhibits the synthesis of TNF-alpha and leukotriene. Paraxanthine has also been shown to increase the transport of potassium and calcium ions in skeletal muscles.

Theobromine, being the second highest percentage metabolite of caffeine is an alkaloid that can also be found in chocolate, tea leaves and the kola nut. Theobromine is then metabolized to xanthine, which is also a PDE inhibitor with very similar effects to that of paraxanthine.

Theophylline is the third metabolite of caffeine and is generally found in large amounts in tea leaves and cocoa. So not only does caffeine have an effect on your brain and body, but also so does its metabolites, these include side-effects as well.

That's where L-Theanine comes in.

What is L-Theanine?

L-theanine is an amino acid that is most commonly found in tea leaves as well as certain mushrooms. Theanine structure is very similar to that of glutamine and glutamate.

L-Theanine has been shown to react with neuroreceptors related to the regulation and production of GABA. GABA is known to have various functions in the body, but it is most commonly known to affect stress messages as well as generating alpha brain-waves. Alpha brain-waves are generally associated with feelings of being physical calm and relaxation without feeling heavy or listless. Studies also suggest that alpha brain-waves may boost creativity and reduce symptoms of depression.
L-theanine binds to ionotropic glutamate receptors, including the kainate and AMPA receptors as antagonists, and as an agonist to NMDA receptors. L-Theanine also binds to group 1 metabotropic glutamate receptors, known to be related to learning and memory. These mechanisms lead to changes in synaptic excitability, and may even induce postsynaptic responses.

Research also suggests that L-theanine may improve mental focus and clarity and might even sharpen one's senses. L-Theanine may also promote healthy stress levels. In addition, human studies have shown that L-theanine paired with green tea extract improved delayed recognition times and immediate recall scores.

How L-Theanine and Caffeine Work In Synergy

Caffeine can be very effective, however, it does come with some drawbacks. The most common of this being over-stimulation which is generally associated with the feeling of “jitters” and not to mention the dreaded crash once it wears off. Caffeine can also cause sleep disorders when abused. Overconsumption of caffeine may also result in a tolerance to the compound, forcing you to take more to get the same benefits.

That’s where L-theanine comes in again. L-Theanine effectively takes the ‘edge’ off of caffeine when combined together. L-Theanine natural affinity to inhibit certain receptors and its calming effect can curb the feelings of jitters, hyperactivity and other side-effects generally experienced with caffeine. L-Theanine has also shown to inhibit glutamate excitotoxicity, making it ideal for balancing out unwanted side-effects resulting from caffeine. More importantly, the synergistic combination of L-Theanine and Caffeine may also increase the potential benefits of both compounds.

Studies have shown the following potential effects of combining L-Theanine & Caffeine:
  • Support Mental Focus

  • Increased Memory Recall

  • Support Reaction Time

  • Promotes Better Mind-Muscle Connection

  • Greater Mental Clarity and Cognition


Studies have suggested that caffeine by itself has the ability to improve accuracy and attention. However, when combining L-Theanine and Caffeine, it improves both the speed and accuracy when performing the same tasks on caffeine alone. Thus, studies suggest that both these compounds have a host of their own benefits, but using them together can greatly increase these benefits.

Would you like to try L-Theanine + Caffeine for yourself? ZA Nootropics offers Caffeine and L-Theanine Capsules, carefully measured for the best combination. You can also try our standalone L-Theanine capsules or powder to add with your own coffee brew.

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