Energy drinks vary more than you'd think — from around 150mg of caffeine in a Monster to up to 300mg in a Reign. The best one for you depends on whether you want all-day energy, a workout boost, or a lower-sugar option, and how much you want to pay. 

The best energy drink brands compared

Each of the big energy drink brands has a slightly different character. Here's how the main ones stack up:

Caffeine content varies by can size and product line — always check the specific can.

Which energy drink has the most caffeine?

If raw caffeine is what you're after, Reign sits at the top end of the mainstream brands, with up to around 300mg in a can depending on the line. C4 and Celsius land around 200mg, while a standard Monster is around 150–160mg. For reference, a regular Red Bull is about 80mg in a 250ml can.

More caffeine isn't automatically better, though. The right amount depends on your tolerance and what else you've had that day — which is worth keeping in mind before reaching for the strongest can on the shelf.

Best energy drink by need

The “best” energy drink really comes down to what you want it for:

•     For all-day energy: Monster is the versatile all-rounder — a moderate caffeine hit that works for a long workday, study session or gaming, available in regular and zero-sugar.

•     For workouts: C4 and Reign lean towards fitness, with higher caffeine and added performance ingredients like beta-alanine. C4 in particular blurs the line between energy drink and pre-workout.

•     For a lower-calorie option: Celsius and the various zero-sugar lines give you the caffeine without the sugar, which suits anyone watching calories.

•     For a milder boost: A standard Monster or a smaller Red Bull gives you a gentler lift if you're sensitive to caffeine.

Energy drink vs pre-workout: what's the difference?

It's easy to confuse the two, especially as brands like C4 sell both. The simple distinction: an energy drink is mainly about caffeine and a quick, convenient boost, designed for casual drinking. A pre-workout is a supplement built specifically for training, combining caffeine with ingredients like beta-alanine and citrulline at higher doses to support performance.

If you just want energy to get through the day, an energy drink does the job. If you're training and want a performance edge, a proper pre-workout is the better tool. Some fitness-focused energy drinks sit in between, which is part of what makes them popular.

How much caffeine is safe?

For healthy adults, the recommended limit is 400mg of caffeine a day from all sources. That matters with energy drinks, because some carry up to 300mg in a single can — so two cans, or one can plus a couple of coffees, can take you over the limit without you realising.

A few sensible points: keep an eye on your total daily caffeine across drinks and coffee, don't rely on energy drinks to replace sleep, and remember that high-caffeine energy drinks aren't suitable for under-16s — many UK retailers won't sell them to under-16s for this reason. They're also best avoided during pregnancy and by anyone sensitive to caffeine.

Where to buy cheap energy drinks

If energy drinks are a regular part of your routine, buying them at full price soon adds up. Peeko stocks surplus and clearance energy drinks from the big brands — Monster, C4, Reign and more — at a fraction of the usual price, rescued from overproduction and short-dated stock. Browse the energy drinks range to see what's in stock right now, and stock up before they're gone.

Frequently asked questions

Which energy drink has the most caffeine?

Among the mainstream brands, Reign is at the higher end with up to around 300mg of caffeine per can, while C4 and Celsius sit around 200mg and Monster around 150–160mg. Always check the specific can, as caffeine content varies by size and line.

What is the best cheap energy drink?

It depends what you want. Monster is a great-value all-rounder, C4 and Reign suit workouts with higher caffeine and performance ingredients, and Celsius is a lower-sugar option. The best value comes from buying big-brand surplus stock, which is far cheaper than full retail.

What's the difference between an energy drink and pre-workout?

Energy drinks are mainly about caffeine and a quick boost, and are designed for casual drinking. Pre-workout is a supplement built for training, combining caffeine with ingredients like beta-alanine and citrulline at higher doses. Some drinks like C4 blur the line by adding performance ingredients.

How many energy drinks can I drink a day?

For healthy adults, the recommended caffeine limit is 400mg per day from all sources. Since some energy drinks contain up to 300mg in one can, it's easy to reach that limit with one or two cans plus coffee. They aren't suitable for under-16s or during pregnancy.

Where can I buy cheap energy drinks in the UK?

Surplus and outlet retailers like Peeko sell big-brand energy drinks — Monster, C4, Reign and more — at a fraction of the usual price. The range changes as new surplus stock arrives, so it's worth checking back regularly.