Caffeine

Performance

The most effective legal performance booster. Boosts strength, endurance, focus, and pain tolerance — but tolerance builds within weeks.

energyfocusperformancefat-loss

Typical dose

100–300 mg

Evidence

Strong (multiple RCTs / meta-analyses)

Onset time

Acute: 30–60 min

Half-life

5–6 hours (plasma)

Forms

Powder, Capsule, Tablet

Source

synthetic

Best taken with

water

Best time of day

morning

Bioavailability

5/5

Safety rating

4/5

Price per serving

$0.05

Vegan / GF / 3rd-party

✓ / ✓ / ✓

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Vetted brands, third-party testing, ships worldwide.

Common uses

• Energy
• Pre-workout
• Focus
• Fat loss

Effect profile

Strength

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Muscle

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Energy

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Focus

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Mood

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Sleep

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Immunity

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Recovery

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Longevity

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Common side effects

• Jitters
• Insomnia
• Increased heart rate
• GI upset

Avoid if

• Anxiety disorders
• Heart arrhythmias
• Pregnancy (limit 200 mg/day)

Drug interactions

• MAOIs
• Theophylline
• Birth control

Related performance supplements

Caffeine vs Beta-Alanine Caffeine vs Taurine Caffeine vs Betaine Anhydrous Caffeine vs L-Carnitine (Tartrate)

Medical disclaimer

SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements.