Improvement after a supplement is not the same as a comparative result
Start with the comparison. A before-and-after change alone cannot isolate the contribution of an ingredient.
L-Theanine
Selected research topic
Cognition
Some publications still need interpretation checks and are kept separate from the findings below.
- Publications for this topic
- 7
- Human comparison publications
- 0
- Publications needing review
- 7
This result is held for interpretation. That does not mean research found no effect.
Outcome groups needing additional review (8)
- Attention · Distinct papers needing additional review: 1Evidence criteria check: 1
- attention on a switch task · Distinct papers needing additional review: 1Evidence criteria check: 1
- cognitive function · Distinct papers needing additional review: 1Evidence criteria check: 1
- reaction time to attention tasks · Distinct papers needing additional review: 1Evidence criteria check: 1
- Rey-Kim memory quotient · Distinct papers needing additional review: 1Evidence criteria check: 1
- speed and accuracy of performance of the attention-switching task · Distinct papers needing additional review: 1Direction unclear: 1
- susceptibility to distracting information in the memory task · Distinct papers needing additional review: 1Direction unclear: 1
- total cognition composite · Distinct papers needing additional review: 1Evidence criteria check: 1
One paper can appear under multiple measured outcomes or review reasons, so these counts should not be added together.
Representative outcome and study details
Some findings are held for review
Some papers have not cleared source or result review, so their findings are not summarized yet.
No confirmed result is available to summarize with study conditions.
1 publications linked to this result (1 awaiting review included)
- Those papers are not summarized until review is complete.
Data coverage and detailed study classifications
Paper counts are separated by research topic below. One paper may contribute to multiple findings.
Analysis status: Public-ready
Ingredient analysis date:
How the grade was determined: C
The 9.4 evidence score includes 3 independent human studies and 3 clinical studies in the representative benefit area. The C tier remains conservative because of limited repetition across independent human clinical studies.
The grade is based mainly on the research area with the most evidence. It does not mean the same result was found in other areas.
Papers linked to this ingredient overall: 97
Papers linked to this topic 7 · distinct papers 7 · comparison findings need further review · papers needing additional review 7
A publication may appear in more than one count. These numbers should not be added. Ingredient-wide papers, topic-linked papers, and sources in outcome groups use different scopes. Adding source counts may count the same paper more than once.
- Attention: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- attention on a switch task: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- cognitive function: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- reaction time to attention tasks: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- Rey-Kim memory quotient: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- speed and accuracy of performance of the attention-switching task: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- susceptibility to distracting information in the memory task: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- total cognition composite: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
What the research found
Attention
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
attention on a switch task
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
cognitive function
The study needs further checking before its result can be interpreted.
Review · Unknown intervention · General population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
reaction time to attention tasks
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · General population
Within-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Rey-Kim memory quotient
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · Patient group
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
speed and accuracy of performance of the attention-switching task
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
susceptibility to distracting information in the memory task
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
total cognition composite
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · Patient group
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
total cognition composite
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
How to read research findings
How should I read research findings?
Research guidesNo clear difference and an uninterpretable result are different
A reported null comparison contains a result. An abstract without an interpretable comparison leaves a question unresolved.
Paper counts and study counts are different
Count original research separately from research that reanalyzes it. Publication volume is neither replication nor a quality rating.
Side effects and combination findings
Findings from this ingredient alone are shown separately from those involving another supplement or medication.
No combination cautions are available to show in the current data. This does not guarantee safety.
Review 1 combination findings and 0 findings that outperformed an ingredient alone.
Reported improvements with combinations
Combination findings are grouped by how the study compared them. This is not a recommendation to combine ingredients.
Combinations with reported improvement
The combination showed improvement, but each ingredient's contribution is unclear.
CaffeineL-theanine combined with caffeine significantly reduced caffeine-induced tachycardia (17% vs 92%) and state anxiety compared to caffeine alone.