L-theanine is an amino acid (a building block for proteins) that is naturally occurring in green tea leaves. It is renowned for its excellent nootropic properties such as improving memory, enhancing the ability to learn, and providing a calming effect.

L-theanine has a very similar chemical structure to glutamate, an amino acid in our bodies that assists in the transmission of nerve impulses in the brain, and as a result, it provides a whole host of benefits as a natural supplement for brain health.

Benefits and Effects

Nootropics are supplements, drugs, or functional foods that enhance cognitive functions. L-theanine is often recommended as a supplement for people who are suffering from memory diseases such as Alzheimer’s disease and dementia however it has been demonstrated that individuals with healthy brains benefit highly from its positive effects on the brain. It also has the remarkable ability to cross the blood-brain barrier which means that L-theanine is able to reach the brain directly.

L-theanine also has positive effects on stress levels and shown to increase dopamine and serotonin levels in the brain, which are some of the brain’s feel-good chemicals. This is why teas containing L-theanine, such as green tea and oolong tea, are effective at helping people relax.


L-theanine is usually taken with caffeine for best results. A typical dose would be 200 mg L-theanine and 100 mg caffeine. If you’re not a coffee drinker, it may be better to start with a lower dose such as 100 mg L-theanine and 50 mg caffeine while maintaining the 2:1 ratio.

A little experimentation is recommended to find what works best for you.

Particularly anxious individuals may want to leave out the caffeine altogether.


L-Theanine boosts focus and enhances relaxation on its own but is most effective when combined in a stack with other nootropics.

L-Theanine and Caffeine Stack

L-Theanine has demonstrated impressive positive effects on mental performance when “stacked,” or combined, with caffeine.

The combination of L-theanine and caffeine has synergistic effects that promote enhanced cognition and attention.

For that reason, stacking L-theanine with caffeine is one of the most popular choices among those looking for a cognitive boost due to its simplicity, low cost, and effectiveness.

The effects of stacking L-theanine with caffeine include:

  • Improved memory
  • Enhanced focus
  • Increased motivation
  • Boosted mood
  • Reduced anxiety

Caffeine, a stimulant that most people are very familiar with, is primarily found in coffee but can also be found in tea, sodas, and chocolate.

This popular chemical is known for its energy boosting properties which is the reason why so many people love to start their day with a cup of coffee, helping them get them kick-start their brain.

However, when caffeine is combined with L-theanine, the benefits of each are multiplied. Not only that, L-theanine nullifies caffeine’s negative effects which include feeling jittery and anxious.

1x-2x per day

NOTE: For a convenient way to take this stack, we recommend getting caffeine + L-theanine capsules from

L-Theanine Stack for Universal Cognitive Enhancement

For a preformulated nootropic that contains a blend of 11 cognitive enhancing supplements, including L-theanine, designed to optimize a wide array of cognitive functions, we recommend Mind Lab Pro.

Mind Lab Pro’s strategy aims at all aspects of memory, mental performance, mood and stress resistance, and brain repair, and maintenance. Their combination of nootropics is designed to affect brain energy, neurotransmitters, brain blood flow, brain waves, neuroprotection, and regeneration.

Read our Mind Lab Pro review for a detailed overview.

Side Effects

Supplementing with L-theanine is considered extremely safe and has been designated as a GRAS (Generally Recognized as Safe) ingredient by the Food and Drug Administration in the United States.

Some people report minor side effects, such as dizziness or headache, when taken with caffeine but are not widely reported.

Where to Buy

If you’d like to buy L-theanine, here are our recommendations:

Alternatively, if you’d like to take a supplement that contains a blend of 11 cognitive enhancing nootropics, including L-theanine, we recommend Mind Lab Pro. Read our Mind Lab Pro review for a detailed overview.

Closing Thoughts

L-Theanine is a natural and safe amino acid that has many benefits making it a popular choice among those looking for a simple and effective way to boost their mental performance.

Taken alone, taken combined with caffeine, or included in a more advanced nootropic stack, L-theanine may be worth a try.

Planning to start a new supplementation regimen? See our medical disclaimer.