Pre-Workout Supplements

Do you actually need a pre-workout?

No. Pre-workout is an optional supplement, and most formulas are built around caffeine, which many people already get from coffee: the NHS puts a cup of instant coffee at about 100mg of caffeine.

If you already drink coffee, tea or energy drinks, count that caffeine before adding a pre-workout on top. If you want the other ingredients without the caffeine, a stim-free pre-workout is the option to look at.

What is pre-workout and what's in it?

Pre-workout is a powder, shot or capsule taken before training, usually combining caffeine with ingredients such as citrulline, beta-alanine, taurine or creatine. Stim-free versions leave out caffeine and other stimulants.

The mix and the amounts vary a lot between products, which is why the label matters more than the name on the front. UK food supplement rules require the label to state the amount of any substance with a nutritional or physiological effect, along with the recommended daily dose and a warning not to exceed it.

How much caffeine is in a pre-workout?

It varies widely: in the products we've compared, some contain a moderate amount of caffeine per serving, while others deliver 300–400mg in a single full-strength serving. For comparison, EFSA considers single doses of up to 200mg safe for healthy adults, and up to 400mg spread across the whole day.

"That's a significant difference, particularly for beginners or people who train in the evening," says Andy Arshad, who runs SupplementHQ. "Two pre-workouts can look very similar on the shelf but have completely different formulations, caffeine levels and costs per serving."

Check the caffeine per serving on the label, then add up everything else you drink that day.

Should you choose a stim or stim-free pre-workout?

Choose stim-free if you train in the evening, are sensitive to caffeine, or already have caffeine through the day; choose a stimulant formula only if you know how you respond to caffeine and the dose per serving fits your daily total. EFSA notes that even 100mg of caffeine may affect sleep in some adults when taken close to bedtime.

"I believe stimulant-free pre-workouts deserve more attention," says Andy, "particularly for evening gym users, people sensitive to caffeine or those already consuming caffeine throughout the day."

• High-stimulant pre-workout: the highest caffeine per serving. Check the label carefully.
• Moderate-stimulant pre-workout: less caffeine per serving.
• Stim-free pre-workout: no caffeine or other stimulants.
• New to pre-workout? Start with our beginner range or a sample before committing to a full tub.

How do you compare pre-workouts fairly?

Compare the cost per full-strength serving, not the number of servings on the tub, and check that every ingredient amount is listed. Serving claims and proprietary blends are the two things that most often make a product look better than it is.

"A tub advertised as 40 servings might only provide 20 servings when using the manufacturer's recommended full-strength dose," says Andy. "That can make a product appear better value than it actually is. Some brands also use proprietary blends, making it difficult to establish exactly how much of each active ingredient you're getting. Others clearly disclose their ingredient quantities, making comparisons much easier."

How to calculate it (example figures, not a real product): a £30 tub says 40 servings, but the full-strength dose is two scoops. That's 20 full-strength servings, or £1.50 each, not the 75p the front of the tub suggests. Our guide to reading a supplement label shows where to find serving sizes and ingredient amounts.

Is pre-workout bad for you? What are the side effects?

Pre-workout isn't automatically bad for you, but caffeine is the main thing to watch, so the dose per serving and your total daily intake matter most. The ISSN notes that effects on sleep and feelings of anxiety after caffeine vary between people and may be linked to genetics.

Products with added caffeine must carry the warning "Contains caffeine. Not recommended for children or pregnant women", with the caffeine content per daily dose. Don't take more than the label says, and don't combine pre-workouts with other caffeine products. If you have a heart condition or high blood pressure, another medical condition, take medication, or are pregnant or breastfeeding, speak to your GP or pharmacist before using a pre-workout.

Why does pre-workout make you tingle or itch?

The tingling is usually caused by beta-alanine, an ingredient in many pre-workouts. The ISSN position stand says there is no evidence that this tingling is harmful, and that it's commonly felt at doses above 800mg in a standard (non-sustained-release) form.

The same paper says the feeling generally fades within 60 to 90 minutes and is reduced with smaller divided doses or sustained-release formulas. If you'd rather avoid it, check the label for beta-alanine and its amount per serving.

When should you take pre-workout?

Follow the timing on the label; in caffeine research, the most common timing is about 60 minutes before exercise. Think about your bedtime too, because EFSA notes caffeine close to bedtime may affect sleep.

If you train in the evening, that's often the point at which a stim-free pre-workout makes more sense than a stimulant one.

Pre-workout powder or pre-workout shots?

Powders let you measure your own dose, including a smaller one, while pre-workout shots are a fixed, ready-to-drink single serving you can carry in a gym bag. Compare both on caffeine per serving and cost per serving.

Because a shot is a fixed dose, check its caffeine content before you drink it, especially if you've already had coffee that day.

Is there a pre-workout for women?

Pre-workouts marketed to women generally use the same types of ingredients as any other, so compare them the same way: caffeine per serving and cost per full-strength serving. Browse pre-workout for women.

If you're pregnant, the NHS advises no more than 200mg of caffeine a day, and caffeine-containing supplements are labelled as not recommended in pregnancy. Speak to your GP or midwife before using any pre-workout.

What's the best or strongest pre-workout?

There isn't one best pre-workout for everyone, and the strongest isn't necessarily the best. The right one is the one whose caffeine dose, ingredients and cost per serving suit you.

"Customers need to understand what they're taking, how much they're taking and whether the ingredients suit their individual needs," says Andy. "That's the approach we're building at SupplementHQ: comparing ingredient dosages, caffeine content, transparency and genuine cost per serving rather than relying on marketing claims or flashy packaging."

Start with the stimulant level that suits your day, then compare: high-stim, moderate-stim or stim-free.

We sell the products on this page. That's our commercial interest, and it's why we show the evidence alongside them. This page is general information for adults, not personalised medical advice. Caffeine-containing pre-workouts are not recommended for children.

Written by Andy Arshad, SupplementHQ. Last reviewed 10 October 2026.