FitorexCaffeine
A very well established ergogenic aid for almost any sport.
What it is for
Strength and endurance performance, focus and a lower perception of effort.
How it works
An adenosine receptor antagonist: it reduces the sensation of fatigue and increases central nervous system activation.
Dosing
3–6 mg/kg (≈200–400 mg). Start at the low dose to gauge your tolerance.
When to take it
30–60 min before training. Avoid within 8–9 h of bedtime.
Safety
Safe at moderate doses. High doses: anxiety, tachycardia, insomnia.
Side effects
Jitteriness, stomach discomfort, disrupted sleep, mild dependence.
Interactions
It adds to other stimulants; be careful with heavily loaded pre-workouts.
Contraindications
Arrhythmias, uncontrolled hypertension, anxiety, pregnancy (limit to <200 mg/day).
Who it has been studied in
The response varies by genetics (CYP1A2): 'slow metabolisers' tolerate it worse and respond differently.
Frequently asked
Do you build a tolerance?
Yes. Cycling it or lowering the dose for a few days restores sensitivity.
Does it dehydrate you?
The diuretic effect is mild and well tolerated; it is not a practical problem when training.
What this rests on
Wake up and smell the coffee: caffeine supplementation and exercise performance — an umbrella review of 21 published meta-analyses
Grgic J, Grgic I, Pickering C, et al. · 2019 · British Journal of Sports Medicine
Effect: A small-to-moderate effect on muscular strength/power and also on aerobic endurance, consistent across the 21 meta-analyses reviewed.
Limitations: Response varies with genetics (caffeine metabolism) and tolerance from habitual intake; most studies use a single laboratory dose, not real daily consumption patterns.
- Evidence tier
- A
- Quality
- High
- Studies
- >100 RCTs, umbrella reviews
- Consensus
- ISSN position in favour
- Controversy
- Effect size varies with genetics (CYP1A2) and habituation
- Reviewed
- 2024
Strength of evidence out of 5.