Caffeine before a workout

The dose: 3–6 mg per kg

Decades of research point to 3–6 mg of caffeine per kilogram of body weight for a performance boost. For a 70 kg person that's about 210–400 mg — roughly two to four coffees' worth. Start at the lower end (3 mg/kg); going higher rarely helps and adds jitter. Work out your range with the intake calculator, which shows your exercise sweet spot.

The timing: 30–60 minutes before

Caffeine peaks in your blood about 30–60 minutes after you take it, so that's your window before training. For a longer session, this also covers the start of your workout when it matters most.

What it actually does

• Improves endurance — you can sustain effort longer.
• Increases strength and power output.
• Lowers perceived effort — the same workout feels easier.
• Sharpens focus and reaction time.

Don't let it wreck your sleep

Evening workouts are the catch: a pre-workout dose at 6 pm still has a lot of caffeine onboard at bedtime, and that quietly cuts your deep sleep. If you train late, use a smaller dose, or check what's left at bedtime with the half-life calculator.

Coffee vs pre-workout vs pills

They all work — it's the caffeine that matters. Coffee is cheapest and tastes good but its dose varies; pre-workout powders and caffeine pills give a precise, known amount. Pick whatever lets you hit your target reliably.

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Put it into practice: the intake calculator shows your exact 3–6 mg/kg exercise range.