What Does Pre-Workout Actually Do?

Pre-workout is one of the most popular supplements in the gym, but what does it actually do? Here's a straightforward look at what's typically inside and how people use it.

The idea behind it

A pre-workout is a drink you take before training. Most are built around caffeine, alongside a mix of other ingredients such as amino acids and electrolytes. Formulas are usually marketed as either "stim" (caffeinated) or "pump" blends, so it's worth looking past the labels and reading what's actually in each product.

Common ingredients

• Caffeine — the stimulant most "stim" formulas are built around. Caffeine helps increase alertness and improve concentration (from 75 mg per serving).
• Citrulline — an amino acid commonly included in non-stimulant "pump" formulas.
• Beta-alanine — an amino acid that's often behind the tingly skin sensation (paraesthesia) some people notice after taking it.
• Electrolytes — minerals such as sodium, potassium and magnesium that are sometimes added to the mix.

Stim vs non-stim

Stimulant pre-workouts contain caffeine; non-stimulant "pump" formulas don't. Because they're caffeine-free, non-stim options are often chosen for evening sessions or by anyone who prefers to avoid stimulants.

How to use it

Most people take it around 20–30 minutes before training with water. If you're new to it, start with a half scoop to see how you respond, and avoid taking it too close to bedtime if you're sensitive to caffeine.

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A quick note

This article is general information, not medical or nutritional advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle, and should not be used to prevent or treat any illness. Always read the product label, do your own research, and speak to a qualified doctor, pharmacist or registered nutritionist before starting a new supplement — especially if you are pregnant, breastfeeding, under 18, taking medication or managing a health condition.