L-Theanine: A Relaxation Supplement That May Improve Attention

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L-theanine is an amino acid, and is one of the main active components of green tea. It is similar in structure to the amino acid glutamine, and is known to reach the brain following ingestion.

Why Might L-Theanine Be Beneficial?

L-theanine appears to induce relaxation without sedation, and may somewhat reduce anxiety. This means that it may be helpful for ”taking the edge off” stimulants such as caffeine.

Secondary to its relaxation effect, L-theanine may aid sleep quality, though this effect appears to be quite weak.

L-theanine may also improve attention, and so it may have a role to play as a cognition-enhancing supplement.

What Is The Evidence Behind L-Theanine Supplementation?

Studies suggest that L-theanine can improve self-reported relaxation and relaxation as measured by alpha waves in the brain. These effects appear to occur 30 minutes to an hour after ingestion. L-theanine does not appear to reduce anticipatory anxiety. While the magnitude of the L-theanine‘s relaxing effect is notable, the caveat is that these studies were few and were quite small.

L-theanine appears to improve attention task performance and reaction time. A recent double-blind, placebo-controlled study supports this finding and suggests that this effect is dose-dependent. However, the first of these studies suggests that L-theanine might only improve attention in those who experience baseline levels of anxiety.

There is evidence that L-theanine improves sleep quality in healthy adults and in children with ADHD, but its minor effects suggest it may not be a good first-line treatment.

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