For a fizzy afternoon drink, compare caffeine and sugars in the whole can, then check whether the particular flavour is carbonated. Red Bull states 80mg caffeine per 250ml can for its Original and Zero drinks, while Monster Energy lists 160mg per 500ml for its Zero Sugar drink; a zero-sugar label does not mean caffeine-free. If caffeine is a concern, include other drinks and foods consumed that day when deciding whether an energy drink suits you.
The useful comparison depends on whether you care most about sugar, the caffeine in one can or whether caffeine is suitable for the person drinking it.
Check the named variant rather than the brand alone. Monster Energy lists its Zero Sugar drink as carbonated, with 0g sugar per 500ml; a sugar-containing drink calls for a different comparison of the sugars line on its own pack.
A can-size difference matters if you intend to drink the whole can. Red Bull states 80mg caffeine per 250ml for Original and Zero, while Monster Energy states 160mg per 500ml for its Original and Zero Sugar examples.
If you are pregnant or sensitive to caffeine, read the warning and count caffeine from other sources as well. The NHS advises no more than 200mg caffeine a day during pregnancy. Check age-related information when buying for a young person, too.
Start with the can you would actually drink, rather than comparing flavour names or pack fronts. Then check the ingredients and format of that specific variant.
| Priority | What to check | Your needs |
|---|---|---|
| Caffeine per can | Read the caffeine declaration and can volume together. Red Bull states 80mg per 250ml for Original and Zero; Monster Energy states 160mg per 500ml for its Original and Zero Sugar examples. Check the label of any different variant. | I want to know how much caffeine one afternoon can adds, especially when choosing between 250ml and 500ml servings. |
| Sugars and sweeteners | Compare sugars for the whole serving and read the ingredients. Monster Energy lists 0g sugar per 500ml for Zero Sugar and 55g per 500ml for its Original Green drink; those figures do not describe every Monster variant. | A sugar-free option interests me, but I still want to know whether it contains caffeine and which sweeteners are in the drink. |
| Fizz and flavour | Look for “carbonated” or “sparkling” on the named product. Relentless describes White Citrus as carbonated, while Lucozade describes its Alert range as sparkling; check the particular flavour and pack before choosing. | For an afternoon snack, I want a fizzy flavour I recognise, rather than assuming every drink from an energy-drink brand has the same format. |
| Caffeine cautions | Read the pack warning and the caffeine amount for the chosen serving. The NHS advises a daily caffeine limit of 200mg during pregnancy; caffeine from other sources counts towards that total. | I need to consider who will drink it and what else they have had that day before choosing a caffeinated can. |
Monster Energy states that its Zero Sugar drink contains 160mg caffeine per 500ml, and Red Bull states that Zero contains 80mg per 250ml. Removing sugar does not remove the need to compare caffeine.
Check the caffeine declaration for the entire can alongside the sugars line.
The amount consumed changes with the can you choose. Monster Energy lists 55g sugar per 500ml for Original Green; a figure for one product and serving should not be transferred to another flavour or size.
Use the nutrition information on the current pack and compare the amount you expect to drink.
Carbonation is a characteristic of the specific drink. Relentless identifies White Citrus as carbonated, but a brand name by itself does not establish the format of another variant.
Check the named flavour’s description or ingredients for “carbonated” or “sparkling”.
These examples illustrate differences between named drinks and ranges, not a ranking of brands. Check the label of the particular can when changing size or flavour.
A 250ml comparison point for shoppers considering caffeine per can: Red Bull states 80mg caffeine for both its Original and Zero drinks.
Monster Energy lists 500ml figures for its Zero Sugar and Original Green drinks, each with 160mg caffeine; its published figures may vary by region.
Relentless describes White Citrus as a carbonated citrus-flavour energy drink containing caffeine.
Lucozade describes Alert as a sparkling drinks range.
These options cover smaller Red Bull cans and larger zero-sugar Monster cans, including multipacks and a fruit-flavoured variant. Compare the current pack details for the exact drink you intend to have.
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A smaller-can sugar-free option for comparing an afternoon serving. The product information describes 80mg caffeine per 250ml can and lists sweeteners, including aspartame; sugar-free does not mean caffeine-free. Check the current pack if you are sensitive to caffeine.
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A sugar-containing 250ml option if you want to compare a conventional recipe with sugar-free drinks. The product information states 80mg caffeine per can. Read the sugars line on the current pack for the amount in this serving.
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A carbonated, zero-sugar 500ml option for someone comparing larger cans. The product information identifies sweeteners and includes a caffeine warning. Read the caffeine amount on this variant’s current can before deciding how it fits with other caffeine consumed that day.
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A citrus-flavoured, sparkling zero-sugar option in 500ml cans. The product information identifies sweeteners and caffeine. Check this Ultra variant’s current label for the caffeine in the full can rather than borrowing a figure from a different Monster drink.
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A fruit-flavoured 250ml option described with white peach and nectarine flavour and carbonated water. Its product information identifies sugars and caffeine. Check the current can for their amounts; do not assume they match another Red Bull variant.
Use the whole-can amount to understand the serving you would drink, and check the per-100ml declaration when comparing labels. Red Bull states 80mg per 250ml for its Original and Zero drinks; Monster Energy states 160mg per 500ml for its named Original and Zero Sugar examples. Check a different variant separately.
No. Monster Energy lists 0g sugar and 160mg caffeine per 500ml for its Zero Sugar drink, while Red Bull states 80mg caffeine per 250ml for Zero. Read both the sugars information and caffeine declaration.
Look for the caffeine declaration and any high-caffeine warning on the current pack. UK government guidance says drinks other than tea and coffee containing more than 150mg caffeine per litre require a warning label; use the declared amount and can size to assess the serving you are considering.
The NHS advises no more than 200mg caffeine a day during pregnancy, so the caffeine in an energy drink needs to be considered alongside other sources consumed that day. If you want fizz without adding caffeine, consider a non-caffeinated sparkling drink instead.
No UK-wide ban follows from the announced England policy. The Department of Health and Social Care and Department for Education announced an England-only ban on sales of high-caffeine energy drinks to under-16s intended for April 2027, subject to Parliamentary approval. Check current information when buying for a young person rather than treating that future measure as a rule already in force.