Sugar-free energy drinks: what's actually in them
UpdatedΚοινοποίηση
Sugar-free energy drinks replace sugar with sweeteners, but usually keep the same caffeine as the regular version. Many UK energy drinks contain 32 mg of caffeine per 100 ml, which is 80 mg in a 250 ml can and 160 mg in a 500 ml can, with or without sugar. So "sugar-free" changes the sugar and calories, not the caffeine.
Key points
• Sugar-free versions swap sugar for sweeteners such as sucralose, acesulfame K or aspartame.
• The caffeine is usually the same as the regular version: often 32 mg per 100 ml.
• A sugary energy drink can contain up to 20 teaspoons of sugar per can (Action on Sugar, 2015).
• High-caffeine drinks must say "High caffeine content" on the label.
Table of contents
- What's in a sugar-free energy drink?
- Caffeine: sugar-free vs regular
- Sweeteners and label warnings
- Why so many energy drinks went sugar-free
- Age rules
- FAQ
What's in a sugar-free energy drink?
Most sugar-free energy drinks contain:
- Carbonated water
- Caffeine: usually the same amount as the regular version
- Sweeteners instead of sugar
- Acids such as citric acid, and flavourings
- Often taurine and B vitamins, sometimes ginseng or L-carnitine
- Colours and preservatives
Caffeine: sugar-free vs regular
| Drink | Caffeine |
|---|---|
| Red Bull Energy Drink, 250 ml | 80 mg |
| Red Bull Sugarfree, 250 ml | 80 mg |
| Monster Energy Zero Sugar, 500 ml | 160 mg (32 mg/100 ml) |
| Typical energy drink, 250 ml (NHS) | about 80 mg |
Work out your own total: caffeine calculator.
Sources: Red Bull GB FAQ pages; Monster Energy Zero Sugar UK on-pack label; NHS. Checked October 2026. Check the can you buy.
More caffeine figures: How much caffeine is in Monster and Red Bull? · Energy drinks with the least caffeine
Sweeteners and label warnings
Sweeteners used in UK drinks have to be approved food additives. Common ones in energy drinks are sucralose, acesulfame K and aspartame. Drinks with aspartame must state "Contains a source of phenylalanine", which matters for people with the rare condition phenylketonuria (PKU).
Drinks (other than tea and coffee) with more than 150 mg of caffeine per litre must carry the warning "High caffeine content. Not recommended for children or pregnant or breast-feeding women", followed by the caffeine per 100 ml. Most full-strength energy drinks, sugar-free or not, carry this warning.
Why so many energy drinks went sugar-free
Since April 2018, the UK Soft Drinks Industry Levy has charged producers for drinks with added sugar: from April 2025, 19.4p per litre for drinks with 5–8 g of sugar per 100 ml and 25.9p per litre for 8 g or more (GOV.UK). Many brands have since launched or expanded zero-sugar versions.
A sugary energy drink can still contain up to 20 teaspoons of sugar per can (Action on Sugar, 2015). More: Caffeine pouches vs energy drinks: sugar, caffeine and format
Age rules
England plans to ban the sale of high-caffeine energy drinks (more than 150 mg per litre) to under-16s, and this includes sugar-free versions. More: Energy drinks and under-16s: the new UK rules
Optimal Native caffeine pouches are not a drink and contain no sugar: Morning Energy has 200 mg and Daily Flow 75 mg of caffeine per pouch, and Evening Relax is caffeine-free. Optimal Native sells only to adults aged 18 and over. More: Caffeine pouches in the UK
FAQ
Do sugar-free energy drinks have less caffeine?
Usually not. Sugar-free versions typically have the same caffeine as the original, often 32 mg per 100 ml.
What sweeteners are in sugar-free energy drinks?
Commonly sucralose, acesulfame K and aspartame. Check the ingredients list.
Are sugar-free energy drinks banned for under-16s?
The planned ban in England covers high-caffeine energy drinks whether or not they contain sugar.
How much caffeine is in a 500 ml sugar-free energy drink?
At 32 mg per 100 ml, 160 mg.
Read next: Caffeine-free energy drinks · Caffeine in Monster and Red Bull · Caffeine pouches vs energy drinks
Optimal Native is coming to the UK. One stack for the whole day: Morning Energy, Daily Flow and Evening Relax. Pre-orders ship from 15 December 2026.