Quick answer: a drink can only call itself "low sugar" in the UK if it has 2.5g of sugar or less per 100ml. "Sugar free" means 0.5g or less. Most low and zero sugar energy drinks get there with artificial sweeteners, so check what replaced the sugar as well as the sugar itself.
Low and zero sugar energy drinks compared
| Drink | Can | Sugar | Caffeine | Sweetened with | Fizzy |
|---|---|---|---|---|---|
| Red Bull Sugarfree | 250ml | Sugar free | 80mg | Artificial sweeteners | Yes |
| Monster Ultra | 500ml | 0g | 160mg | Artificial sweeteners | Yes |
| Celsius | 355ml | 0g | 200mg | Sucralose, acesulfame K | Yes |
| PÜRCHARGE | 330ml | 3.8g (1.2g per 100ml) | 125mg | Stevia | No, still |
Figures from UK retailer and brand listings, October 2026. Recipes change, so check the can.
Low sugar, sugar free or just "reduced"?
- Sugar free: 0.5g or less per 100ml.
- Low sugar: 2.5g or less per 100ml.
- Reduced sugar: 30% less than the original. Not the same as low. Lucozade Energy Original, for example, has 4.5g per 100ml (17.1g a bottle): less than full-sugar drinks, but not low sugar.
- "Natural sugar" isn't low sugar either. Tenzing, for example, uses sugar from fruit with no sweeteners, but at 4.5g per 100ml (about 11g a can) it sits above the low sugar line.
For context, adults should have no more than 30g of free sugars a day. A full-sugar 500ml energy drink can carry 55g.
What to check besides sugar
- Caffeine. Zero sugar cans often carry the most caffeine. Up to 200mg in one go is generally fine for healthy adults; Celsius hits that in a single can.
- Sweeteners. Plant-based (stevia) or artificial (sucralose, acesulfame K, aspartame). Neither is automatically bad, but you'll be drinking it every day.
- Fizz. If carbonation leaves you bloated, a still drink is easier on a long day. See still vs fizzy energy drinks.
Where PÜRCHARGE fits
We make it, so judge for yourself. At 1.2g of sugar per 100ml it qualifies as low sugar, sweetened with stevia rather than artificial sweeteners, and it's still. Each can has 125mg of caffeine from green coffee, electrolytes and 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.
More on our low sugar energy drink page, or shop the range.
FAQs
What's the difference between low sugar and sugar free?
Low sugar means 2.5g or less per 100ml. Sugar free means 0.5g or less. Both are legal definitions in the UK.
Are sugar-free energy drinks healthier?
They remove the sugar, but often keep a high caffeine dose and use artificial sweeteners. Check the whole label, not just the sugar line.
Which low sugar energy drink has no artificial sweeteners?
Of those above, only PÜRCHARGE, which uses stevia. Tenzing also skips sweeteners, but at 4.5g per 100ml it isn't low sugar.
