For exam revision, choose a sugar-free energy drink only if its caffeine amount for the whole can suits your plans; sugar-free does not mean caffeine-free. Red Bull UK lists 80 mg in a 250 ml Sugarfree can, while Monster Energy UK lists 160 mg in a 500 ml Zero Sugar can. If caffeine affects your sleep, or the drink is for a younger student, consider a non-caffeinated snack or drink instead.
A sugar-free label answers one question, not both. Red Bull UK lists 80 mg caffeine in a 250 ml Sugarfree can; Monster Energy UK lists 160 mg in a 500 ml Zero Sugar can. Compare the amount in the can you intend to drink.
Remember coffee, tea, cola and other caffeine sources alongside an energy drink. The European Food Safety Authority’s 2015 assessment says daily intakes up to 400 mg from all sources do not raise safety concerns for adults in the general population, except pregnant women. Individual sensitivity and the time you drink caffeine still matter.
The question may be whether to choose an energy drink at all, rather than which sugar-free variety to buy. A BMJ Open review of evidence on young people found an association between frequent energy-drink consumption and poorer wellbeing; that association does not establish cause and effect. For under-16s in England, the government has announced a planned restriction on sales of high-caffeine energy drinks from April 2027, subject to Parliamentary approval.
Start with the exact drink’s sugar declaration, then compare caffeine for the amount you expect to consume and consider when you will drink it.
| Priority | What to check | Your needs |
|---|---|---|
| Sugar status | Read the sugar declaration and ingredients on the exact variety. A drink containing sweetener may also contain sugar: Relentless UK lists sucrose and glucose in Cherry, and describes White Citrus as containing sugar and sweetener. | I want a drink without sugar, so I need to check the variety rather than rely on the brand name. |
| Whole-can caffeine | Compare caffeine alongside can size. Red Bull UK lists 80 mg per 250 ml Sugarfree can; Monster Energy UK lists 160 mg per 500 ml Zero Sugar can. Count other caffeine consumed that day. | A larger can might be more than I intend to drink in one revision break. I want to know the caffeine amount before deciding whether to finish it. |
| Timing and age | Consider when you will drink it and whether caffeine affects your sleep. For an under-16 in England, check the applicable sales rules when purchasing a high-caffeine energy drink; an announced restriction is planned from April 2027, subject to Parliamentary approval. | If I am revising late, or choosing for a younger student, a non-caffeinated snack or drink may make more sense than an energy drink. |
The stated caffeine amounts differ even between these sugar-free options: Red Bull UK lists 80 mg per 250 ml Sugarfree can, while Monster Energy UK lists 160 mg per 500 ml Zero Sugar can.
Read the caffeine amount and can size together, rather than choosing from the sugar wording alone.
Monster Energy UK lists 160 mg caffeine for its 500 ml Zero Sugar can. Caffeine from other drinks and foods also counts towards daily intake.
Decide how much of the can you expect to drink, then consider it alongside coffee, tea, cola and other caffeine sources.
A sugar-free drink still contains caffeine. A BMJ Open review found that frequent energy-drink consumption among young people was associated with poorer wellbeing, although the evidence did not establish causation.
If caffeine affects your sleep, choose a non-caffeinated snack or drink for a late revision break instead.
Red Bull UK lists 80 mg caffeine in a 250 ml Sugarfree can.
Monster Energy UK lists its 500 ml Zero Sugar can as containing 0 g sugar and 160 mg caffeine.
Lucozade describes Zero as a zero-sugar soft-drink range, while its Energy range contains glucose.
The Relentless UK product information for Cherry and White Citrus does not identify either variety as sugar-free.
These Joybuy listings are multipacks of sugar-free energy drinks. Check the caffeine information for each can when choosing a drink for a revision break.
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The 250 ml can makes the whole-can amount straightforward to check for a revision break. Red Bull UK lists 80 mg caffeine per 250 ml Sugarfree can; count it alongside other caffeine you consume that day.
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This zero-sugar 12-can pack is another option for a revision break. Check the caffeine amount and can size on this specific variety before deciding how much to drink.
No. Sugar and caffeine are separate things to check. Red Bull UK lists 80 mg caffeine in a 250 ml Sugarfree can, while Monster Energy UK lists 160 mg in a 500 ml Zero Sugar can; their can sizes differ too.
Start with the caffeine amount for the whole can you expect to finish, then include other caffeine sources consumed that day. The European Food Safety Authority’s 2015 assessment says up to 400 mg per day from all sources does not raise safety concerns for adults in the general population, except pregnant women; it does not remove the need to consider individual sensitivity or timing.
Check the rules that apply where the drink is being sold rather than assuming one position covers every UK nation. In England, the government has announced a restriction on sales of high-caffeine energy drinks to under-16s, intended from April 2027 subject to Parliamentary approval. The announcement does not make a sugar-free label an age-suitability check.
A sugar-free energy drink still contains caffeine. If caffeine affects your sleep, choose a non-caffeinated snack or drink for a late break rather than relying on the sugar-free wording.