---
title: "Higher-Dose Caffeine + L-Theanine: Sharper, Less Tired"
url: https://stacklist.com/card/b0f82eae-d55e-4cc7-87de-1304b10bce58
source_url: "https://pubmed.ncbi.nlm.nih.gov/18006208/"
stack: https://stacklist.com/c/education/stack/ed5a3ae2-37d9-4b9f-acfb-16fc78c07ec8
summary: "This randomized, double-blind, placebo-controlled study examined the cognitive and mood effects of L-theanine (250 mg) and caffeine (150 mg) in isolation and combination. The combination improved reaction time, visual processing accuracy, mental fatigue ratings, and alertness while reducing headaches, suggesting L-theanine and caffeine beverages have a different pharmacological profile than caffeine alone."
tags: "caffeine, l-theanine, cognitive-performance, clinical-trial, neuroscience, mood-effects, drug-interaction"
key_entities: "L-Theanine (concept), Caffeine (concept), Cognitive Performance (concept), Mental Fatigue (concept), Rapid Visual Information Processing (concept), Drug Interaction (concept), Double-Blind Randomized Controlled Trial (technology)"
classification: "reference"
content_hash: "sha256:6f4d03c73dc84ea42f17fa76d08d35447562bb577aebbd710ea463572ea63633"
acp_version: "0.2"
token_counts_approximate: 1004
visibility: public
agent_accessible: true
status: "final"
---

# Higher-Dose Caffeine + L-Theanine: Sharper, Less Tired

Full text links Cite Display options Display options Format Abstract PubMed PMID Linked Discoveries Abstract L-Theanine is an amino acid found naturally in tea. Despite the common consumption of L-theanine, predominantly in combination with caffeine in the form of tea, only one study to date has examined the cognitive effects of this substance alone, and none have examined its effects when combined with caffeine. The present randomised, placebo-controlled, double-blind, balanced crossover study investigated the acute cognitive and mood effects of L-theanine (250 mg), and caffeine (150 mg), in isolation and in combination. Salivary caffeine levels were co-monitored. L-Theanine increased 'headache' ratings and decreased correct serial seven subtractions. Caffeine led to faster digit vigilance reaction time, improved Rapid Visual Information Processing (RVIP) accuracy and attenuated increases in self-reported 'mental fatigue'. In addition to improving RVIP accuracy and 'mental fatigue' ratings, the combination also led to faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy. 'Headache' and 'tired' ratings were reduced and 'alert' ratings increased. There was also a significant positive caffeine x L-theanine interaction on delayed word recognition reaction time. These results suggest that beverages containing L-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone. PubMed Disclaimer Publication types Randomized Controlled Trial Actions Search in PubMed Search in MeSH Add to Search MeSH terms Adolescent Actions Search in PubMed Search in MeSH Add to Search Adult Actions Search in PubMed Search in MeSH Add to Search Affect / drug effects* Actions Search in PubMed Search in MeSH Add to Search Attention / drug effects Actions Search in PubMed Search in MeSH Add to Search Caffeine / metabolism Actions Search in PubMed Search in MeSH Add to Search Caffeine / pharmacology* Actions Search in PubMed Search in MeSH Add to Search Central Nervous System Stimulants / metabolism Actions Search in PubMed Search in MeSH Add to Search Central Nervous System Stimulants / pharmacology* Actions Search in PubMed Search in MeSH Add to Search Cognition / drug effects* Actions Search in PubMed Search in MeSH Add to Search Cross-Over Studies Actions Search in PubMed Search in MeSH Add to Search Double-Blind Method Actions Search in PubMed Search in MeSH Add to Search Drug Interactions Actions Search in PubMed Search in MeSH Add to Search Female Actions Search in PubMed Search in MeSH Add to Search Glutamates / metabolism Actions Search in PubMed Search in MeSH Add to Search Glutamates / pharmacology* Actions Search in PubMed Search in MeSH Add to Search Headache / psychology Actions Search in PubMed Search in MeSH Add to Search Humans Actions Search in PubMed Search in MeSH Add to Search Male Actions Search in PubMed Search in MeSH Add to Search Memory / drug effects Actions Search in PubMed Search in MeSH Add to Search Memory, Short-Term / drug effects Actions Search in PubMed Search in MeSH Add to Search Mental Fatigue / psychology Actions Search in PubMed Search in MeSH Add to Search Psychomotor Performance / drug effects Actions Search in PubMed Search in MeSH Add to Search Reaction Time / drug effects Actions Search in PubMed Search in MeSH Add to Search Saliva / chemistry Actions Search in PubMed Search in MeSH Add to Search Visual Perception / drug effects Actions Search in PubMed Search in MeSH Add to Search Substances Central Nervous System Stimulants Actions Search in PubMed Search in MeSH Add to Search Glutamates Actions Search in PubMed Search in MeSH Add to Search Caffeine Actions Search in PubMed Search in MeSH Add to Search theanine Actions Search in PubMed Search in MeSH Add to Search LinkOut - more resources Full Text Sources Elsevier Science Other Literature Sources The Lens - Patent Citations Database Medical MedlinePlus Health Information