Caffeine Anhydrous

Overview

Caffeine is one of the most consistently effective performance aids in sports nutrition. It is also the supplement most commonly overdone. Start at the low end of the range, avoid late-day dosing to protect sleep, and never stack with additional stimulants without medical clearance.

Benefits

• →Improves perceived exertion and alertness
• →Supports performance in endurance and repeated-sprint efforts
• →Enhances focus during training

Best for

Stacks with

Side effects

• • Jitters, anxiety, or elevated heart rate at higher doses
• • Sleep disruption if taken later in the day
• • Withdrawal headaches on abrupt cessation

Warnings & cautions

• ⚠Do not exceed ~400 mg/day for most healthy adults (per FDA guidance).
• ⚠Avoid or reduce dose if you have hypertension, heart arrhythmia, or anxiety disorders.
• ⚠Pregnant and breastfeeding people should limit total caffeine per medical guidance.
• ⚠Not recommended for children and adolescents.
• ⚠People sensitive to stimulants should start with a much smaller test dose.

Drug & condition interactions

• • May interact with stimulant medications and some psychiatric medications.
• • Combining with other stimulants (yohimbine, ephedrine) can significantly raise cardiovascular risk — avoid.

Evidence notes

Human trials consistently show small performance benefits for endurance, power, and repeated-sprint work. Individual response varies substantially.

Research references

• [1] Guest NS et al. International Society of Sports Nutrition position stand: caffeine and exercise performance. — J Int Soc Sports Nutr, 2021; 18:1