Pre-Workout Supplements: What Works and How to Stay Safe
Caffeine, citrulline and beta-alanine explained, safe caffeine limits, and when to skip a pre-workout entirely.
Updated 9 October 2026 · General information, not medical advice.
A pre-workout is a drink you take 20–30 minutes before training for energy and focus. Most of the effect comes from a few ingredients.
The ingredients that matter
- Caffeine — improves alertness and performance. Most adults tolerate up to about 400 mg a day in total, from all sources (tea and coffee count).
- L-citrulline — supports blood flow; studied doses are around 6–8 g.
- Beta-alanine — helps in efforts lasting 1–4 minutes; causes a harmless tingling feeling.
- Creatine — sometimes added, but works the same whenever you take it.
Use it safely
- Start with half a scoop to see how you react.
- Don't take it within 6 hours of bedtime — poor sleep cancels the benefit.
- Don't stack it with coffee or energy drinks.
- Drink water through your session.
Who should avoid pre-workouts
People with high blood pressure, heart rhythm problems, anxiety disorders, pregnancy, or those on regular medicines should speak to their doctor first. Under-18s should skip stimulants.
Do you even need one?
No. A cup of coffee and a good meal 1–2 hours before training gives most of the same effect. A pre-workout is a convenience, not a requirement.