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Caffeine (1,3,7-Trimethylxanthine)
Blocks adenosine receptors to boost alertness, reaction time, and endurance — one of the most proven ergogenic aids.
What the evidence says
Caffeine appears to help in 22 of 25 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2008–2026 with a typical study size of 71 participants.
Based on 146 studies · 26 meta-analyses · 52 RCTs · 142,640 total participants
Confidence
HighWhat the studies found
By outcome
See full supplement plans that include Caffeine.
Caffeine has an evidence score of 9.5/10 — very strong evidence based on 95 indexed studies, including 23 meta-analyses. Blocks adenosine receptors to boost alertness, reaction time, and endurance — one of the most proven ergogenic aids.
The commonly studied dose of Caffeine is 100-200mg. Research points to an estimated optimal dose around 200mg, with a minimum effective dose near 75mg. Individual response varies — start low and adjust.
The best time to take Caffeine is in the morning. Taking it with food is preferred. Caffeine is a methylxanthine adenosine receptor antagonist with a half-life of 3-7 hours (CYP1A2-dependent).
Creatine
Likely helpsIncreases phosphocreatine stores for faster ATP regeneration, boosting strength, power output, and cognitive function under stress.
CoQ10
Likely helpsEnhances mitochondrial energy production and acts as a lipid-soluble antioxidant — critical for heart health and depleted by statins.
Last reviewed May 2026 · evidence from 40 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Caffeine is a natural stimulant found in coffee, tea, and cacao. It's one of the most well-researched performance enhancers, with strong evidence for improving alertness, reaction time, and endurance exercise performance. Effects are dose-dependent, and tolerance develops with regular use.
Prevents the tiredness signal from reaching your brain
Increases adrenaline and dopamine activity
Enhances fat burning during exercise
How Caffeine works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
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100-200mg
Can be taken without food
| Form | Type |
|---|---|
| 💊Pill/capsule for precise dosing | Recommended |
| 💊Coffee (~95mg per 8oz) | Alternative |
| 🍵Tea (~50mg per 8oz) | Alternative |
| 💊Pre-workout supplements | Alternative |
Pills allow precise dosing. Coffee and tea contain beneficial compounds but variable caffeine content.
Minimum: 1 days
Optimal: days
Cycling: Consider periodic breaks (1-2 weeks) to reset tolerance. Tolerance to stimulant effects develops within 1-2 weeks of daily use.
Note: Avoid within 6-8 hours of bedtime. Half-life is 5-6 hours. Effects are stronger on an empty stomach but may cause stomach upset.
You can get caffeine from these foods and drinks. Doses are typical per-serving estimates — actual content varies by brand, brew, cooking, etc.
95 mg per cup
8 oz mug, medium roast. Range 70–140 mg depending on brew time and bean.
63 mg per shot
1 oz single shot. Doppio = 2 shots.
155 mg per cup
12 oz serving. Concentration varies widely; some commercial cold brews exceed 200 mg.
47 mg per cup
8 oz brewed, 3–5 min steep. English Breakfast / Earl Grey range 40–70 mg.
80 mg per serving
Standard 8.4 oz can. Larger 16 oz cans typically 160 mg.
70 mg per cup
1 tsp (~2 g) matcha powder whisked in 8 oz water. Ceremonial-grade tends higher; culinary lower.
28 mg per cup
8 oz brewed, 2–3 min steep. Gyokuro / shade-grown teas are higher in L-theanine.
Based on multiple meta-analyses showing 3-6mg/kg optimal dosing. Performance benefits plateau around 200-300mg with increased jitteriness at higher doses.
Feel more awake and mentally sharp
Better concentration on tasks
Especially for endurance activities
Anxiety or restlessness at higher doses
Can interfere with sleep if taken too late
Limit to 200mg/day maximum
Not recommended; limit to minimal amounts
Use with caution or avoid; may worsen symptoms
Additive stimulant effects; may increase heart rate and blood pressure
May increase caffeine effects and cardiovascular stress
Can slow caffeine metabolism, intensifying effects
Tip: Lower dose or take with L-theanine
Tip: Avoid afternoon/evening consumption
Tip: Lower dose
Tip: Taper gradually rather than stopping abruptly
L-theanine smooths out caffeine's edge
Alert focus without jitteriness; the 'smart caffeine' stack
Different mechanisms for performance
Caffeine for endurance/alertness, creatine for power output
Common nootropic stack for focus
Enhanced alertness and cognitive performance
Common pre-workout combination
BCAAs for muscle support, caffeine for energy and focus
Classic combination for fat oxidation
Enhanced thermogenic and cognitive effects
Popular combination for energy and focus
Enhanced alertness and sustained energy
Different ergogenic mechanisms
Additive performance benefits
Enhanced and prolonged energy when combined
Faster onset (caffeine) with sustained energy (theacrine)
Both support alertness through different mechanisms
Enhanced mental performance; start with lower doses of each
Caffeine is generally safe at recommended doses, with a few precautions worth noting. The most commonly reported side effects are jitteriness/anxiety, insomnia, increased heart rate. Use caution if any of these apply to you: Severe anxiety disorders; Uncontrolled high blood pressure; Heart arrhythmias.
Alpha-GPC
Likely helpsCrosses the blood-brain barrier to fuel acetylcholine synthesis — supports focus, memory, and power output in athletes.
Increased theophylline toxicity risk
Dangerous cardiac stimulation, arrhythmias