Caffeine

Does caffeine work?

What is Caffeine?

Caffeine is a substance found naturally in many plants. It’s also abundant in coffee, tea, soda, and chocolate, and is taken in powders, pills, or an ingredient in energy supplements. Adenosine slows down nerve cell activity and causes drowsiness. Caffeine binds to the same receptors as adenosine, blocking its effects. This causes increased neuron firing. The pituitary gland registers this activity as an emergency. This releases hormones causing increased breathing, heart rate, blood flow to muscles, and blood pressure. It also decreases blood flow to the stomach and releases sugar into the blood for extra energy. Read More

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Overall Effectiveness Rating for Caffeine

The overall effectiveness rating for caffeine is 2 out of 3. This rating means there is some evidence that using caffeine may lead to positive results. This rating also means that some evidence does not back up all claims. Below you can find individual ratings for specific claims.

Overall Confidence Rating for Caffeine

There are 60 studies in the database on caffeine; the confidence rating is 140. A score above 80 means the effectiveness rating for this supplement is reliable. A score under 80 means there is insufficient evidence to ensure a reliable effectiveness rating. Note, this rating is for caffeine as a whole. There are also individual ratings for the claims below.

Products Containing Caffeine

Products Containing Caffeine
Savage Roar
EndoRush
Alpha Burn
Geek Sauce
Ultra Pump Preworkout
Full list of all 264 products containing Caffeine.

Individual Claims

The overall ratings above do no necessarily reflect each claim about caffeine. Individual claims can have higher or lower ratings. For example, some supplements may have a lot of backing for one claim, but be completely useless for another. Click on claims below for more information.

Performance Claims Effectiveness Rating Confidence Rating
improve agility
improve cardiovascular endurance
improve cycling performance
improve muscular endurance
improve running performance
improve sports performance
improve sprint performance
decrease fatigue
increase strength
improve cycling sprint performance
increase alertness

Mental Health Claims Effectiveness Rating Confidence Rating
improve cognitive ability
improve memory
improve mood

General Health Claims Effectiveness Rating Confidence Rating
improve insulin sensitivity

References

Title of Study
Acute caffeine ingestion enhances strength performance and reduces perceived exertion and muscle pain perception during resistance exercise
Acute caffeine intake before and after fatiguing exercise improves target shooting engagement time
Acute effects of a caffeine-containing supplement on bench press and leg extension strength and time to exhaustion during cycle ergometry
Acute effects of caffeine in volunteers with different patterns of regular consumption
Acute ingestion of sugar-free red bull energy drink has no effect on upper body strength and muscular endurance in resistance trained men
Acute Specific Effects of Caffeine-containing Energy Drink on Different Physical Performances in Resistance-trained Men
Caffeine and performance over consecutive days of simulated competition
Caffeine and Sprint Cycling Performance: Effects of Torque Factor and Sprint Duration
Caffeine and sprinting performance: dose responses and efficacy
Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation
Caffeine effects on mood and memory
Caffeine Improves Basketball Performance in Experienced Basketball Players
Caffeine improves muscular performance in elite Brazilian Jiu-jitsu athletes
Caffeine improves physical and cognitive performance during exhaustive exercise
Caffeine increases performance in cross-country double-poling time trial exercise
Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men
Caffeine restores engagement speed but not shooting precision following 22 h of active wakefulness
Caffeine supplementation and multiple sprint running performance
Caffeine supplementation and peak anaerobic power output
Co-ingestion of caffeine and carbohydrate after meal does not improve performance at high-intensity intermittent sprints with short recovery times
Effect of caffeine ingestion after creatine supplementation on intermittent high-intensity sprint performance
Effect of Caffeine on Attention and Alertness Measured in a Home-Setting, Using Web-Based Cognition Tests
Effect of Caffeine on Golf Performance and Fatigue during a Competitive Tournament
Effect of caffeine on target detection and rifle marksmanship
Effect of post-exercise caffeine and green coffee bean extract consumption on blood glucose and insulin concentrations
Effect of repeated caffeine ingestion on repeated exhaustive exercise endurance
Effects of acute sleep deprivation and caffeine supplementation on anaerobic performance
Effects of caffeine in non-withdrawn volunteers
Effects of caffeine on mood and memory
Effects of caffeine on mood and performance: a study of realistic consumption
Effects of caffeine on prolonged intermittent-sprint ability in team-sport athletes
Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land
Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading
Effects of low doses of caffeine on cognitive performance, mood and thirst in low and higher caffeine consumers
Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers
Effects of repeated doses of caffeine on performance and alertness: new data and secondary analyses
Effects of sodium phosphate and caffeine loading on repeated-sprint ability
Energy Drink Doses Of Caffeine And Taurine Have A Null Or Negative Effect On Sprint Performance
Enhancement of High-Intensity Actions and Physical Performance During a Simulated Brazilian Jiu-Jitsu Competition With a Moderate Dose of Caffeine
Enhancing physical performance in elite junior tennis players with a caffeinated energy drink
Enhancing physical performance in male volleyball players with a caffeine-containing energy drink
Improvement of Sprint Performance in Wheelchair Sportsmen With Caffeine Supplementation
Increases in cycling performance in response to caffeine ingestion are repeatable
Independent and combined effects of carbohydrate and caffeine ingestion on aerobic cycling performance in the fed state
Little effect of caffeine ingestion on repeated sprints in team-sport athletes
Multiple effects of caffeine on simulated high-intensity team-sport performance
Physiological and cognitive responses to caffeine during repeated, high-intensity exercise
Psychostimulant and other effects of caffeine in 9- to 11-year-old children
Slow release caffeine and prolonged (64-h) continuous wakefulness: effects on vigilance and cognitive performance
The acute effects of a caffeine-containing supplement on bench press strength and time to running exhaustion
The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities
The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players
The effect of acute pre-workout supplementation on power and strength performance
The effect of caffeine as an ergogenic aid in anaerobic exercise
The effect of ephedra and caffeine on maximal strength and power in resistance-trained athletes
The effects of alpha-glycerylphosphorylcholine, caffeine or placebo on markers of mood, cognitive function, power, speed, and agility
The effects of caffeine ingestion on time trial cycling performance
The effects of different doses of caffeine on endurance cycling time trial performance
The effects of supplementation with P-Synephrine alone and in combination with caffeine on resistance exercise performance
The ingestion of a caffeinated energy drink improves jump performance and activity patterns in elite badminton players