Caffeine
A widely studied stimulant taken for alertness and physical performance.
Supplements
Research records
Historical source snapshot. Not freshly verified, not a recommendation. Study findings, community accounts and app defaults are not interchangeable.
Publication suitability · 2026-10-15: Historical reference only; not a clinical verification. Clinical, regulatory, efficacy, safety and dose claims are not independently established by this review.
Caffeine
A widely studied stimulant taken for alertness and physical performance.
Evidence category: Systematic review. This describes the source category, not approval or certainty.
Regulatory statement in source: Not separately recorded; do not infer approval from the evidence category.
Caffeine is a naturally occurring methylxanthine stimulant found in coffee, tea and cacao that works mainly by blocking adenosine receptors in the central nervous system. It is one of the most extensively studied psychoactive compounds, with decades of research examining effects on alertness, cognitive function and physical performance across military, occupational and athletic settings.
Benefits reported in the imported source
- Improves alertness, vigilance and reaction time at low to moderate intake
- Improves endurance, time-trial and high-intensity sprint performance in athletes
- Effects are consistent across a large and long-standing body of research
Risks and limits
- Higher intake is linked with jitteriness, anxiety and sleep disruption
- Effects on memory and complex decision-making are inconsistent
- Tolerance develops with regular use, altering response over time
Source bottom line: Evidence for alertness and physical performance benefits is strong and consistent across a large body of research, though effects on higher-order cognition remain mixed.
Uncertainty: Reference information only. Not medical advice.
Study protocols — reports, not instructions
Healthy adults across military, occupational and athletic contexts, synthesized from the trials reviewed
- Reported regimen
- Doses of approximately 40 mg (about 0.5 mg/kg) up to 300 mg (about 4 mg/kg) evaluated for cognitive effects; doses exceeding roughly 200 mg (about 3 mg/kg) evaluated for physical performance effects
- Duration
- Acute, single-dose administration in most trials reviewed
- Reported outcome
- Low-to-moderate doses improved alertness, vigilance, attention and reaction time; higher doses improved time-to-exhaustion, time-trial performance, muscle strength and endurance, and high-intensity sprint performance
- Source
- A review of caffeine's effects on cognitive, physical and occupational performance - PubMed
Claim provenance
evidence.json#/catalog:supplement:caffeine/protocols/0
Community and practice descriptions
Accounts of a practice are not evidence of safety or effectiveness. Words such as “standard”, “safe” or “recommended” describe the source account, not verified consensus or this wiki’s advice. Commercial and self-published citations are retained for traceability, not vendor endorsement or independent clinical corroboration.
Unverified imported account — How Caffeine Improves Exercise Performance - Healthline
An imported authored paraphrase, not a quotation or a recommended protocol.
Review: unverified historical account. The imported wording is preserved for attribution; its full clinical, dosing, efficacy or consensus claims have not been independently established. Unvalidated source account; no validated human dosing population or animal-to-human equivalence is inferred.
Imported wording: An exercise-nutrition guide describes regular caffeine intake through coffee, energy drinks and caffeinated soft drinks, alongside caffeine anhydrous supplements.
Historical research outcome: verified-description · 2026-10-06
The original numerical amounts were presented by the page as recommendations and study-based amounts. The revised description retains explicit consumption forms without implying an observed common dose.
- https://www.healthline.com/nutrition/caffeine-and-exercise: verified-description — The live page names regular intake through coffee, energy drinks and caffeinated soda, and separately discusses caffeine anhydrous supplements. Dose and efficacy recommendations were excluded.
Pharmacokinetic context
Historical half-life estimate: 5 hours. Kaplan et al. 1997, J Clin Pharmacol, PMID 9378841; Bonati et al. 1982, Clin Pharmacol Ther, PMID 7083737 — adult reference value, nonlinear/dose-dependent, ranges 3.5-10.5h depending on smoking, pregnancy and CYP1A2 genotype Population/route context and estimates may differ. This is not a schedule or a verified human dosing rule.
Source references
Snapshot provenance
Source ID: catalog:supplement:caffeine. Commit: adc7684614f9439b41d91a3312b62e7982c7e20e. Review state: historical-not-reverified. Authored links are retained separately from the canonical evidence links in the public data. App templates/defaults and rejected drafts are archived, not deployed.
Related entries and components
None listed.