Supplement
Supports broad cellular function with category-specific mechanisms.[1451,2894,2968, etc.]
Superscript reference numbers link to the Sources bibliography.
Composite Rating
Blends evidence depth, community direction, safety friction, and completeness.
Evidence Intensity
100/100
High depth from human/RCT/meta counts
Community Direction
33
Positive Lean • confidence Minimal
Safety Friction
100/100
High signal from adverse/interaction markers
Data Completeness
100%
Studies 15 • mentions 3 • links 25
Not medical advice. This product is for educational and informational purposes only. It does not diagnose, treat, cure, or prevent any disease and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.
FDA disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Results may vary. Not intended for use by pregnant or nursing women, individuals under 18, or those with known medical conditions without physician consultation.
If you are experiencing a medical emergency, call 911 or your local emergency number immediately.
Goal alignment: Longevity, Metabolic Health, Energy.[474,634,819, etc.]
Dose guide: Human-study daily dose: 6 mg-400 mg/day (higher-confidence extraction from PubMed abstracts)..[474,634,819, etc.]
Category
Other
Evidence Tier
HIGH
Daily Guide
Human-study daily dose: 6 mg-400 mg/day (higher-confidence extraction from PubMed abstracts).
Dosing Guide
Human-study daily dose: 6 mg-400 mg/day (higher-confidence extraction from PubMed abstracts).[1451,, etc.]
Clinical Depth
Humans: 4,317 • RCTs: 769 • Meta: 174
Cohort / Real-World
Cohort signals: 0
Safety Markers
Adverse signals: 2,196 • Interactions: 3,190
Freshness, trend, and study timeline for this item
Status
Trend
↑ Growing evidence base
Depth
5985 total studies · 2 recent
Timeline
Animal-only studies
13,040
Total indexed
5,985
Human studies
4,317
Interaction signals
3,190
In vitro / tissue
3,036
Safety adverse signals
2,196
Weighted direction score: 33 (Positive Lean)
High when >=2 human meta-analyses, or >=5 human RCTs with substantial human literature volume.
Animal-only studies
13,040
Total indexed
5,985
Human studies
4,317
Interaction signals
3,190
In vitro / tissue
3,036
Safety adverse signals
2,196
Randomized trials
769
Meta-analyses
174
Distribution of evidence by study design strength
Evidence Strength: High
Composite of study volume, RCTs, and meta-analyses
PMID 36870101 • 2023 Jun
The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.
Sleep Med Rev
Open PubMedPMID 36615805 • 2022 Dec 28
Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis.
Nutrients
Open PubMedPMID 30335479 • 2019
The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials.
Crit Rev Food Sci Nutr
Open PubMedBenefit reports: 2
Adverse reports: 1
No-effect reports: 0
Mixed reports: 0
Unclear reports: 0
Signal confidence: 0.00
Benefits
Adverse
No Effect
Insufficient empirical signal for a directional adjustment.
Reddit evidence: 0 mentions (confidence 0.00).
aggregate • benefit
Aggregate community signal: 3 directional mentions (benefit 2, adverse 1, no-effect 0, mixed 0).
Open mentionamazon
Amazon search for Caffeine
Rating: n/a | Reviews: n/a
Open productEvidence Sources
PUBMED • Humans + preclinical triage
Counts aggregated from automated literature sweep and tiering rules.
Outcome: Tier HIGH; humans 4317, RCTs 769, meta-analyses 174.[1451,2894,2968, etc.]
Open sourcePUBMED • 2023 • Human evidence curation set
PMID 36870101 from Sleep Med Rev.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,,, etc.]
PMID 29167102 • 2017 Nov 22
Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes.
BMJ
Open PubMedPMID 35239468 • 2023 May
Effects of caffeine chewing gum supplementation on exercise performance: A systematic review and meta-analysis.
Eur J Sport Sci
Open PubMedPMID 39972597 • 2025 Dec
Effects of different dietary supplements on athletic performance in soccer players: a systematic review and network meta-analysis.
J Int Soc Sports Nutr
Open PubMedPMID 33838673 • 2021 Apr 10
Effects of supplementation with main coffee components including caffeine and/or chlorogenic acid on hepatic, metabolic, and inflammatory indices in patients with non-alcoholic fatty liver disease and type 2 diabetes: a randomized, double-blind, placebo-controlled, clinical trial.
Nutr J
Open PubMedPMID 38542677 • 2024 Mar 7
The Effect of Creatine Nitrate and Caffeine Individually or Combined on Exercise Performance and Cognitive Function: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial.
Nutrients
Open PubMedPMID 33759701 • 2022
Effects of Creatine and Caffeine Supplementation During Resistance Training on Body Composition, Strength, Endurance, Rating of Perceived Exertion and Fatigue in Trained Young Adults.
J Diet Suppl
Open PubMedPMID 31492050 • 2019 Sep 5
Caffeine Supplementation Improves Anaerobic Performance and Neuromuscular Efficiency and Fatigue in Olympic-Level Boxers.
Nutrients
Open PubMedPMID 34024173 • 2021 Aug
Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men.
J Biol Rhythms
Open PubMedPMID 11665810 • 2001
The effects of red bull energy drink on human performance and mood.
Amino Acids
Open PubMedPMID 34234088 • 2021 Jul 1
Creatine Supplementation: An Update.
Curr Sports Med Rep
Open PubMedPMID 33388079 • 2021 Jan 2
International society of sports nutrition position stand: caffeine and exercise performance.
J Int Soc Sports Nutr
Open PubMedPMID 29540367 • 2018 Apr
IOC consensus statement: dietary supplements and the high-performance athlete.
Br J Sports Med
Open PubMedAmazon signal: 0 products scanned (confidence 0.00).
GNC signal: 0 products scanned (confidence 0.00) [BLOCKED].
PerimeterX / captcha block encountered.
Search fetch failed: Failed to fetch after retries: https://old.reddit.com/search.json?raw_json=1&sort=relevance&t=year&limit=12&q=%22caffeine%22%20(supplement%20OR%20dosage%20OR%20stack%20OR%20side%20effects%20OR%20review)%20(subreddit%3ASupplements%20OR%20subreddit%3ANootropics%20OR%20subreddit%3ABiohackers%20OR%20subreddit%3Alongevity%20OR%20subreddit%3ANutrition%20OR%20subreddit%3AHubermanLab%20OR%20subreddit%3ASleep%20OR%20subreddit%3AFitness%20OR%20subreddit%3Aketoscience%20OR%20subreddit%3AStackAdvice)
Fallback search failed: Failed to fetch after retries: https://old.reddit.com/search.json?raw_json=1&sort=comments&t=all&limit=16&q=%22caffeine%22%20(supplement%20OR%20capsule%20OR%20powder%20OR%20experience%20OR%20results%20OR%20side%20effects)
Broad search failed: Failed to fetch after retries: https://old.reddit.com/search.json?raw_json=1&sort=new&t=all&limit=16&q=caffeine
Use adverse/interactions PubMed signal counts for screening; perform clinician review before high-dose or multi-drug stack use.
Human-study daily dose signal: 6 mg-400 mg/day (confidence HIGH).
Extracted from 5 dosing mentions across 3 PubMed studies (mg/day).
Imported legacy community score: 10.0/10 (heuristic mapping confidence 1.00).
Imported legacy monthly cost signal: ~$5.00.
Legacy community note: The most widely consumed and praised performance enhancer. Universally used. Main debate is about timing, dose, and tolerance management. Coffee preferred over pills in most health communities for additional polyphenol benefits.
Community Sources
PUBMED • 2022 • Human evidence curation set
PMID 36615805 from Nutrients.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2019 • Human evidence curation set
PMID 30335479 from Crit Rev Food Sci Nutr.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2017 • Human evidence curation set
PMID 29167102 from BMJ.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2023 • Human evidence curation set
PMID 35239468 from Eur J Sport Sci.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2025 • Human evidence curation set
PMID 39972597 from J Int Soc Sports Nutr.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2021 • Human evidence curation set
PMID 33838673 from Nutr J.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2024 • Human evidence curation set
PMID 38542677 from Nutrients.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2022 • Human evidence curation set
PMID 33759701 from J Diet Suppl.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2019 • Human evidence curation set
PMID 31492050 from Nutrients.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2021 • Human evidence curation set
PMID 34024173 from J Biol Rhythms.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2001 • Human evidence curation set
PMID 11665810 from Amino Acids.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2021 • Human evidence curation set
PMID 34234088 from Curr Sports Med Rep.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2021 • Human evidence curation set
PMID 33388079 from J Int Soc Sports Nutr.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open sourcePUBMED • 2018 • Human evidence curation set
PMID 29540367 from Br J Sports Med.
Outcome: See linked PubMed abstract for methods and outcomes.[1451,2894,2968, etc.]
Open source