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L-Theanine

Exercise performance

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.

A distinct publication count is not available.

Other outcomes and study details

Distinct publications linked to this topic: 1

  • Those papers are not summarized until review is complete.

The current data are insufficient to judge results for this topic.

Research topics to explore

Research topics to explore

Review findings reported in each research area.

Topics with more linked papers appear first.

  • Stress and mood

    Related papers 17 · human comparison papers 2

    View results
    • HDRS · Improvement reported · Some studies included patients or people with a deficiency
    • markers of stress · No clear difference between groups

    More outcome groups: 10

  • Sleep

    Related papers 15 · human comparison papers 3

    View results
    • Insomnia symptoms · No clear difference between groups
    • Sleep quality · No clear difference between groups · Some studies used more than one ingredient · Some studies included patients or people with a deficiency

    More outcome groups: 13

  • Cognition

    Related papers 7 · comparison findings need further review

    View results
    • Attention · Interpretation held
    • attention on a switch task · Interpretation held

    More outcome groups: 6

  • Glucose and metabolic health

    Related papers 2 · comparison findings need further review

    View results
    • Body weight · Interpretation held
    • muscle glycogen · Interpretation held
  • Blood lipids

    Related papers 1 · comparison findings need further review

    View results
    • serum levels of cholesterol · Interpretation held
    • triglycerides · Interpretation held
  • Blood pressure and vascular health

    Related papers 1 · comparison findings need further review

    View results
    • blood-pressure increases · Interpretation held
  • Digestion and gut health

    Related papers 1 · comparison findings need further review

    View results
    • intestinal inflammation · Interpretation held
  • Exercise performance

    Related papers 1 · comparison findings need further review

    View selected result
  • Fatigue and energy

    Related papers 1 · comparison findings need further review

    View results
    • self-reported tiredness · Interpretation held
  • Immune and respiratory health

    Related papers 1 · comparison findings need further review

    View results
    • splenic organ index · Interpretation held
  • Nutrient status

    Related papers 1 · comparison findings need further review

    View results
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 1 · distinct papers 1 · comparison findings need further review · papers needing additional review 1

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.

    Stress and mood

    What the research found

    markers of stress

    No clear difference in this measurement was found between the compared groups.

    Controlled study in people · Separable contribution · General population

    Between-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    HDRS

    The study reported improvement in this measurement.

    Controlled study in people · Separable contribution · Patient group

    Between-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    HAMD-21 score

    A change was reported before and after use. Its cause cannot be isolated.

    Other evidence · Separable contribution · Patient group

    Within-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    anti-stress effects

    The study needs further checking before its result can be interpreted.

    Review · Ingredient combination · Unspecified 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

    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.

    anxiolytic and calming effect

    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.

    DASS-42 stress score

    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.

    depression

    The study needs further checking before its result can be interpreted.

    Review · Unknown intervention · Unspecified 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.

    depressive-like behaviors

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · Patient group

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    overall mood

    The study needs further checking before its result can be interpreted.

    Meta-analysis · 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

    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.

    state anxiety

    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.

    subjective stress response to a multitasking cognitive stressor

    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.

    Tension-Anxiety scores

    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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Review · Single ingredient · Unspecified population

    The comparison could not be confirmed.

    Analysis coverage and paper counts

    2 papers · 2 measured outcomes

    2 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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Review · Single ingredient · Unspecified 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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Other evidence · Unknown intervention · Unspecified population

    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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Other evidence · Unknown intervention · Unspecified population

    The comparison could not be confirmed.

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Review · Unknown intervention · Unspecified 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.

    Sleep

    What the research found

    Insomnia Severity Index

    No clear difference in this measurement was found between the compared groups.

    Controlled study in people · Single ingredient · Unspecified population

    Between-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    Mean PSQI

    No clear difference in this measurement was found between the compared groups.

    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

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    sleep efficiency

    The study reported improvement in this measurement.

    Controlled study in people · Single ingredient · Patient group

    Between-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    total PSQI score

    A change was reported before and after use. Its cause cannot be isolated.

    Other evidence · Ingredient combination · Patient group

    Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.

    Within-group comparison

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    sleep-onset latency

    A change was reported, but the comparison could not be confirmed.

    Review · Unknown intervention · Patient group

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    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.

    morning sleepiness

    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.

    overall subjective sleep quality score

    The study needs further checking before its result can be interpreted.

    Meta-analysis · 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.

    sleep duration

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Ingredient combination · Unspecified population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    sleep duration

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Separable contribution · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    sleep efficiency

    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.

    sleep latency

    The study needs further checking before its result can be interpreted.

    Controlled study in people · Single ingredient · General population

    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.

    sleep onset latency

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Ingredient combination · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    sleep onset latency

    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.

    sleep problems

    The study needs further checking before its result can be interpreted.

    Controlled study in people · Single ingredient · General population

    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.

    Sleep quality

    The study needs further checking before its result can be interpreted.

    Other evidence · 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

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    subjective daytime dysfunction

    The study needs further checking before its result can be interpreted.

    Meta-analysis · 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.

    subjective sleep onset latency

    The study needs further checking before its result can be interpreted.

    Meta-analysis · 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.

    total sleep time

    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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Controlled study in people · Ingredient combination · Unspecified 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.

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Other evidence · Unknown intervention · Unspecified population

    The comparison could not be confirmed.

    Analysis coverage and paper counts

    1 paper · 1 measured outcome

    Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.

    Cognition

    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.

    Glucose and metabolic health

    What the research found

    Body weight

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · Unspecified population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    muscle glycogen

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · Unspecified population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    Blood lipids

    What the research found

    serum levels of cholesterol

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    triglycerides

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    Blood pressure and vascular health

    What the research found

    blood-pressure increases

    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.

    Digestion and gut health

    What the research found

    intestinal inflammation

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    Exercise performance

    What the research found

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Controlled study in people · Unknown intervention · Unspecified population

    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.

    Fatigue and energy

    What the research found

    self-reported tiredness

    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.

    Immune and respiratory health

    What the research found

    splenic organ index

    The study needs further checking before its result can be interpreted.

    Animal study · indirect · Single ingredient · General population

    This finding comes from animal or cell research. It does not establish the same effect in people.

    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.

    Nutrient status

    What the research found

    Unspecified measured outcome

    The study needs further checking before its result can be interpreted.

    Controlled study in people · Single ingredient · Unspecified population

    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 guides

    Side effects and combination findings

    Findings from this ingredient alone are shown separately from those involving another supplement or medication.

    Caution findings
    0
    Findings from individual and combined use, plus reviewed cautions
    Key precautions
    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.
    These findings were reported in studies. They do not predict an individual's experience.

    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.