Quick answer: the best energy drink depends on what you want to avoid. If it's sugar, pick a can under 5g. If it's jitters, stay around 75 to 150mg of caffeine. If it's bloating, go still. Here's how the UK's popular cans compare.
UK energy drinks compared
| Drink | Can | Caffeine | Sugar | Fizzy | Sweeteners |
|---|---|---|---|---|---|
| Red Bull | 250ml | 80mg | 27.5g | Yes | None |
| Monster Energy | 500ml | 160mg | 55g | Yes | Sucralose |
| Monster Ultra | 500ml | 160mg | 0g | Yes | Yes |
| Lucozade Energy Original | 380ml | About 46mg | 17.1g | Yes | Acesulfame K, sucralose |
| Celsius | 355ml | 200mg | 0g | Yes | Sucralose, acesulfame K |
| Tenzing | 250ml | 80mg | 11.25g | Yes | None |
| PÜRCHARGE | 330ml | 125mg | 3.8g | No, still | Stevia |
Figures from UK retailer and brand listings, October 2026. Recipes change, so check the can.
How to pick yours
- Sugar: adults should have no more than 30g of free sugars a day. A 500ml full-sugar can can be nearly double that.
- Caffeine: up to 400mg a day and 200mg in one go is generally fine for healthy adults. Caffeine contributes to increased alertness, but more isn't always better.
- Fizz: if carbonated drinks leave you bloated, a still drink is easier to sip through a long day. See still vs fizzy energy drinks.
What stands out
- Most sugar: full-sugar Monster at 55g a can.
- Most caffeine: Celsius at 200mg, the full single-dose guideline in one can.
- Zero sugar: Monster Ultra and Celsius, both using artificial sweeteners.
- Low sugar without artificial sweeteners: Tenzing and PÜRCHARGE.
- The only still option here: PÜRCHARGE.
Where PÜRCHARGE fits
We make it, so we're biased. It's a still energy water with 125mg of caffeine from green coffee, 3.8g of sugar from fruit juice, L-theanine (from green tea extract), enXtra®, rhodiola, Panax ginseng, electrolytes, nine vitamins. Vitamins B6 and B12 contribute to the reduction of tiredness and fatigue. Not for under-16s, pregnant or breastfeeding women. Max two cans a day.
See how it compares on our best energy drink UK page or shop the range.
FAQs
Which UK energy drink has the least sugar?
Zero-sugar versions like Monster Ultra and Celsius have none, but use artificial sweeteners. Of the cans without artificial sweeteners above, PÜRCHARGE has the least at 3.8g.
Which energy drink has the most caffeine?
Of these, Celsius at 200mg a can. Monster and Monster Ultra follow at 160mg.
What's the healthiest energy drink?
Use our five checks in best healthy energy drinks UK.
