Studies

Explore research connecting ingredients and health goals.

20 ingredient–goal connections

GoalReported findings
SupportiveMixedNo effectAdverseUnclassified

FitnessandCaffeine

255published studies

Supportive

The available research supports caffeine as a performance aid for endurance exercise, with pooled trials showing improvements in running and cycling. It can also improve movement speed during resistance exercise and some measures of muscular endurance, strength and sport-specific performance. These benefits primarily reflect performance after taking caffeine, rather than evidence that it builds lasting aerobic fitness or changes body composition.

Effects are not uniform across people or activities. Some controlled trials find no benefit, and improvements in selected tasks do not consistently extend to broader sport performance or maximal oxygen uptake. Research disagrees about how strongly habitual caffeine use or genetic differences affect the response, so neither provides a reliable explanation for every result.

More caffeine does not consistently produce better performance. In caffeine-habituated athletes, high intakes have failed to improve strength or endurance, and research during exercise in hot conditions has found increased body temperature and heat strain without a performance benefit. These limits qualify the overall favorable evidence for immediate exercise performance.

255 linked studies · 24 sampled for detail · Sep 27, 2026

Study types

  • Randomized trial151
  • Meta-analysis42
  • Narrative review24
  • Clinical trial17
  • Systematic review14
  • Guideline / consensus3
  • Non-randomized trial3
  • Cross-sectional study1

Published by year

  • 35Earlier
  • 32010
  • 72011
  • 32012
  • 32013
  • 62014
  • 22015
  • 52016
  • 62017
  • 62018
  • 122019
  • 112020
  • 272021
  • 172022
  • 142023
  • 352024
  • 332025
  • 302026

Findings over time

Numbers above bars show study counts. Earlier groups years before 2010.

202630 studies

  • Supportive22
  • Mixed5
  • No effect3
  • Adverse0
  • Unclassified0

Population over time

Reported participants by publication year. Select a year to see the total and reporting coverage.

— Participant count not reported. Earlier groups years before 2010.

20261,708 reported participants

Counts reported by 20 of 30 studies. 10 without a reported count.

Totals sum reported counts across studies and reviews; participants may overlap between sources.

Explore this goal

Showing 5 top-ranked studies for Caffeine and Fitness.

Top studies

Caffeine · FitnessHighest ranked first
  1. Effect of caffeine ingestion on cycling performance: a systematic review and meta-analysis.
    2026Meta-analysis226 participants20 studies reviewed

    Frontiers in nutrition

    Finding Acute caffeine reduced cycling completion time and increased mean power, with no significant effect on heart rate or perceived exertion.

    SupportiveView source for Effect of caffeine ingestion on cycling performance: a systematic review and meta-analysis. (opens in a new tab)
  2. Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis.
    2023Meta-analysis254 participants21 studies reviewed

    Nutrients

    Finding Caffeine improved time to exhaustion in running tests with a medium standardized effect (g=0.392; 95% CI 0.214–0.571; p<0.001).

    SupportiveView source for Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis. (opens in a new tab)
  3. Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis.
    2021Meta-analysis12 studies reviewed

    Sports medicine (Auckland, N.Z.)

    Finding Across pooled studies, caffeine favored resistance-exercise movement velocity with SMD 0.62 (95% CI 0.39–0.84; p<0.001).

    SupportiveView source for Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis. (opens in a new tab)
  4. Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial.
    2024Randomized trial76 participants

    Nutrients

    Finding Compared with placebo, caffeine improved velocity and power-output measures during muscular strength and power testing in both sexes.

    SupportiveView source for Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial. (opens in a new tab)
  5. Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine.
    2022Meta-analysis60 studies reviewed

    Sports medicine (Auckland, N.Z.)

    Finding Across 60 studies, caffeine improved performance versus placebo, with no influence from relative habitual caffeine consumption.

    SupportiveView source for Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine. (opens in a new tab)

Counts reflect published studies in our database, not the strength of a benefit. A study may appear in more than one connection.