5 Reasons to Combine L-Theanine With Caffeine

L-theanine and caffeine: a synergistic combination

Long before most nootropic supplements existed, people have used caffeine in coffee beans and other plants as a mental and physical booster.

To date, caffeine remains one of the most widely used over-the-counter stimulants. It can be taken on its own as a nootropic supplement to improve cognitive performance, and it is also a common ingredient in many nootropic formulas.

There is no doubt that caffeine works very well as a wakening and psychostimulant agent, and it is significantly more tolerated and less toxic than most stimulant drugs, such as amphetamines.

There is, however, one common downside to caffeine: it tends to cause irritability, nervousness and anxiety for many people.

So, what can possibly be done to eliminate or mitigate those annoying adverse effects?

One trick that has been found helpful is to take L-theanine together with caffeine.

What is L-Theanine?

It is an amino acid that is naturally found in certain plants, such as green tea leaves. It is an analogue of the amino acids L-glutamate and L-glutamine.

Studies have found that L-theanine affects several neurotransmitters and receptors in the brain. There is some evidence that it raises the levels of GABA, dopamine and serotonin in some areas of the brain.[1]

Many people take L-theanine supplements to help them calm down, improve mental performance, and reduce stress and anxiety.

5 Reasons to Take L-Theanine with Caffeine

The following are five reasons why L-theanine makes a perfect companion to caffeine, and why this combo has become one of the top-selling OTC nootropics.

  1. It is a natural relaxing substance that doesn’t cause drowsiness.[2][3]
  2. It reduces stress and anxiety.[4][5]
  3. It works synergistically with caffeine to promote alertness and better cognitive performance.[6][7]
  4. It is a safe substance with no significant adverse effects. Moreover, it counteracts some of the negative effects of caffeine.
  5. It has potential neuroprotective effects that may help slow down cognitive decline.[8][9]

How to Take L-Theanine?

Besides being a natural component in green tea, which you can drink hot or cold, L-theanine is also available as a dietary supplement that can be found in powder and capsule forms.

There haven’t been enough clinical trials on this substance to determine its optimal dosage, however, the standard dosages used in most supplements range from 50mg to 250mg.

When used with caffeine, there are two dosages that are commonly used:

  • 200mg L-Theanine + 100mg Caffeine: This combo has more of a relaxing effect with a minor stimulant effect.
  • 100mg L-Theanine + 200mg Caffeine: If you want an extra awakening effect, then this combo offers an additional kick of caffeine.

Note: As with any other supplement, the efficacy of L-theanine varies from one user to another. You may not experience a more significant effect than you would from drinking a cup or two of green tea!

Is L-Theanine Safe?

Yes, L-theanine is well-tolerated and safe for daily consumption within standard dosages. High dosages (up to 400mg per day) have been used in studies without any reported adverse effects.

It is not recommended to take a total dosage of more than 400mg per day, and you shouldn’t need to.

People who have low blood pressure and those taking medications to reduce blood pressure should be careful when supplementing with L-theanine as it may cause a further drop in blood pressure.

L-theanine has a mild sedative effect, and while it normally does not cause sleepiness, some people reported that it made them feel sleepy. In such case, lowering the dosage is recommended.

Since it affects several neurotransmitter systems in the brain, L-theanine can potentially interact with certain stimulant and sedative drugs.

There is no clinical data about its possible drug interactions, but general precautions are advised.


  1. https://www.ncbi.nlm.nih.gov/pubmed/17182482/
  2. https://www.ncbi.nlm.nih.gov/pubmed/18296328/
  3. https://www.mdpi.com/2306-5710/2/2/13/htm
  4. https://www.ncbi.nlm.nih.gov/pubmed/26797633/
  5. https://www.ncbi.nlm.nih.gov/pubmed/23107346/
  6. https://www.ncbi.nlm.nih.gov/pubmed/21040626/
  7. https://www.ncbi.nlm.nih.gov/pubmed/18681988/
  8. https://www.ncbi.nlm.nih.gov/pubmed/21477654/
  9. https://www.ncbi.nlm.nih.gov/pubmed/31145971/

Leave a Reply

Your email address will not be published. Required fields are marked *