Amino Acid Amino Acids Oral

L-Theanine

Promotes relaxation and focus without sedation. Commonly found in tea.

Sci.γ-L-Glutamylethylamide Theanine Suntheanine
1 form
Oral

About L-Theanine

L-Theanine is a non-proteinogenic amino acid that is primarily found in tea leaves and is known for its ability to promote relaxation and focus without sedation. It modulates brain neurotransmitter systems, increasing levels of GABA, serotonin, and dopamine, and influences alpha brain wave activity.

Official resources

Fact sheets from the NIH Office of Dietary Supplements related to this ingredient group.

At a glance

Approval status

GRAS

Compare All Forms

1 form

Compare supplement forms of L-Theanine by absorption quality and what your body actually gets from each:

High Moderate Low
Form Absorption Steps to absorb Notes Action
Suntheanine

Patented, pure-form L-theanine for relaxation and focus. Non...

  • UNII: 8021PR16QO
  • CAS: 3081-61-6
  • Label category: synthetic
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Also appears on labels as

Additional names seen on supplement labels for forms of this ingredient (beyond the main aliases above).

gamma-glutamylethylamide, L-Theanine, N5-ethyl-L-glutamine

Type: Amino Acids

Building blocks of proteins. Essential amino acids must be obtained from diet, while non-essential can be synthesized by the body.

Absorption: Amino acids are generally well-absorbed. Some forms (like citrulline) are more effective than others (like arginine).

Interactions: Generally safe but high doses can cause digestive issues. Some amino acids can affect neurotransmitter levels.

Watch out for

Possible interactions or cautions — talk to a healthcare provider if unsure.

  • May interact with sedatives and stimulants

Potential Benefits

Benefits associated with L-Theanine forms:

Sleep Quality Relaxation Focus (with Caffeine) Stress & Anxiety Reduction Cognitive Support & Focus Sleep Quality Support

And 2 more benefits...

Potential Side Effects

Side effects associated with L-Theanine forms:

Headache How serious: Mild Low Blood Pressure How serious: Mild Gastrointestinal Discomfort How serious: low

What does the research say?

Research indicates that L-Theanine can enhance relaxation and cognitive performance, particularly in stressful situations, by modulating neurotransmitter levels.