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Evidence-Based Supplement Research

Evidence-Based Supplement Research

L-Theanine and Improved Reaction Time

Doses used in studies

mg/day: 100–400 (median 250, IQR 100–400) — 1 study
mg/kg single-dose: 6 (median 6, IQR 6–6) — 1 study

Safety in these studies

Overall tolerabilityReported
L-theanine, a non-proteinic amino acid found in tea, is known to enhance attention particularly in high doses, with no reported adverse effects.
from: L-theanine improves neurophysiological measures of attention in a dose-dependent manner: a

2 of 2 papersPopulation:

Effect of single or combined caffeine and L-Theanine supplementation on shooting and cognitive performance in elite curling athletes: a double-blind, placebo-controlled study.
- 2023-10-10
- RCT
- Journal of the International Society of Sports Nutrition 20(1)
- - Umut Yilmaz
  - Yusuf Buzdagli
  - Muhammed Lütfü Polat
  - Yusuf Bakir
  - Burak Ozhanci
  - Sena Alkazan
  - Halil Ucar
- PubMed: 37815006
- DOI: 10.1080/15502783.2023.2267536
11 Insights on
- Improved Reaction Time
- High evidence
- Athletes
during the NR task (F=4.743, P = .001, ηp2 = .653), the combined intake of CAF and THE significantly improved reaction times compared to the intake of single CAF, THE, or PLA.
Effect
Neutral
Effect size
Small
Significant
No
Dose
6 mg/kg single dose THE
L-theanine improves neurophysiological measures of attention in a dose-dependent manner: a double-blind, placebo-controlled, crossover study.
- 2020-08-11
- RCT
- Nutritional neuroscience 25(4)
- - Tharaka L Dassanayake
  - Chanaka N Kahathuduwa
  - Vajira S Weerasinghe
- PubMed: 32777998
- DOI: 10.1080/1028415x.2020.1804098
4 Insights on
- Improved Reaction Time
- High evidence
- Adults
No dose-response effect was observed in P3b amplitude, pre-attentive ERP components or reaction time.
Effect
Neutral
Effect size
Small
Significant
No
Dose
100, 200 and 400 mg