Theanine

Related Terms

2-Amino-4-(ethylcarbamoyl)butyric acid, 2,4-dinitrophenyltheanine derivative (DNP-theanine), 5-N-ethylglutamine, amino acid theanine (5-N-ethylglutamine), black tea (Camellia sinensis), D/L-theanine, D-theanine, epitheaflavic acids, gamma-glutamylethylamide, green tea (Camellia sinensis), L-N-ethylglutamine, L-theanine, oolong tea, Suntheanine?, theaflavins, thearubigins.
Select combination products: Theanine SereneT (theanine, valerian, taurine).

Background

Theanine is an amino acid found naturally in tea. Besides caffeine, theanine has been identified as a major component of tea. While younger and fresher tea leaves tend to be richer in caffeine, older leaves tend to have higher theanine levels; furthermore, the withering process of tea production also increases theanine content.
Some evidence suggests that theanine affects mental performance and reduces blood pressure. Research has examined the cognitive effects of this substance alone and when combined with caffeine.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Theanine has historically been used as a relaxing agent. Limited research suggests that theanine may have a slight relaxing effect but not significantly reduce anxiety. Additional research is needed in this area.

 C


Theanine has historically been used as a relaxing agent. Limited research suggests that theanine may have a slight relaxing effect but not significantly reduce anxiety. Additional research is needed in this area.

 C


Limited research suggests that theanine may counteract the effect of caffeine on blood pressure. Additional research is needed in this area.

 C


Limited research suggests that theanine may counteract the effect of caffeine on blood pressure. Additional research is needed in this area.

 C


The mood effect of theanine has been examined when combined with caffeine. Theanine alone had few effects on mood. The combination of theanine and caffeine had improved mood effects not seen with either treatment alone. Additional research is needed in this area.

 C


The mood effect of theanine has been examined when combined with caffeine. Theanine alone had few effects on mood. The combination of theanine and caffeine had improved mood effects not seen with either treatment alone. Additional research is needed in this area.

 C


The effect of theanine on cognition (mental performance) has been examined when combined with caffeine. Theanine alone slowed overall reaction time. The combination of theanine and caffeine had improved mood effects not seen with either treatment alone. Additional research is needed in this area.

 D


The effect of theanine on cognition (mental performance) has been examined when combined with caffeine. Theanine alone slowed overall reaction time. The combination of theanine and caffeine had improved mood effects not seen with either treatment alone. Additional research is needed in this area.

 D
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (18 years and older)
For anxiety, a single dose of 200 milligrams of Suntheanine? has been taken by mouth. L-theanine is thought to be most effective for stress and anxiety in the range of 50-200 milligrams, with effects being felt within 30 minutes and lasting for 8-10 hours. It has been suggested that a maximum dose is 1,200 milligrams daily. However, additional research is needed in this area.
For blood pressure control, a single dose of 200 milligrams theanine has been taken by mouth.
For cognition (mental performance), a single dose of 200-250 milligrams has been taken by mouth.
For mood, a single dose of 200-250 milligrams has been taken by mouth.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Interactions

Interactions with Drugs
Theanine may cause low blood pressure. Caution is advised when using medications that may also lower blood pressure. People taking drugs for blood pressure should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Theanine may also interact with anticancer agents (Adriamycin?, cisplatin, doxorubicin, idarubicin, and pirarubicin), caffeine, dopamine agonists, dopamine antagonists, drugs that affect GABA (serotonin, dopamine, and gamma-aminobutyric acid (GABA)), drugs that affect the immune system, norepinephrine-dopamine reuptake inhibitors, neurologic agents, psychoactive agents, selective serotonin reuptake inhibitors, or serotonin-norepinephrine reuptake inhibitors.

Attribution

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

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