Shoppers comparing sugar
If a sparkling drink is going into the regular basket, compare the sugar stated for each can as well as whether the product is labelled zero sugar. A zero-sugar name does not answer the separate caffeine question.
Who is this choice for?
Shoppers choosing a serving size
A 250ml can and a 500ml can are different servings. Compare caffeine and sugar for the amount you expect to drink, particularly when choosing a multipack.
Households checking who will drink it
Check the warning on the exact drink before adding it to a shared basket. Relentless says its Guava drink is not recommended for children, people sensitive to caffeine, pregnant women or women who are nursing; retailer age policies also matter when buying for under-16s.
What should you compare?
Start with the drink type and the whole serving, then check whether the pack quantity suits how you plan to shop.
| Priority | What to check | Your needs |
|---|---|---|
| Sugar | Read the sugar figure for the whole can, not only per 100ml. Red Bull UK lists 27g sugars for a 250ml Original can; Monster Energy UK lists 55g for a 500ml Original Green can and 0g for a 500ml Monster Energy Zero Sugar can. | I want to know how much sugar is in the drink I would actually finish, whether I choose a standard or zero-sugar version. |
| Caffeine | Compare caffeine in mg per whole can and keep the named variants separate. Red Bull UK lists 80mg per 250ml for Original and Zero; Monster Energy UK lists 160mg per 500ml for Original Green and Monster Energy Zero Sugar. | A smaller can appeals to me, but I still need to check its caffeine figure rather than assuming size alone settles the question. |
| Fizz and drink type | Check that the exact product is described as sparkling or carbonated. Lucozade calls its Energy range a sparkling drink containing glucose and presents its high-caffeine Alert range separately. | If I mainly want a fizzy glucose drink, I do not want to assume it has the same caffeine profile as another drink labelled energy. |
| Pack and serving | Check the number and size of cans or bottles, then read nutrition and caffeine information for one serving. A multipack quantity does not describe what is in each drink. | I’m stocking the weekly basket, so both the number of drinks and the amount I might consume at one time matter. |
| Household suitability | Read the exact product warning and the retailer’s current age policy. Relentless says Guava is not recommended for children, caffeine-sensitive people, pregnant women or women who are nursing. | Before buying for a shared household, I need to know who the drink is intended for and whether the person making the purchase may face an age restriction. |
Common buying mistakes
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Assuming every can has a similar caffeine amount
Red Bull UK lists 80mg caffeine in its 250ml Original and Zero cans, while Monster Energy UK lists 160mg in its 500ml Original Green and Monster Energy Zero Sugar cans. Those figures apply to the named products, not every can of either size.
Compare the stated mg of caffeine for the whole can you expect to drink.
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Reading zero sugar as caffeine-free
Monster Energy Zero Sugar lists 0g sugar and 160mg caffeine per 500ml, according to Monster Energy UK. Red Bull UK lists 80mg caffeine per 250ml of Red Bull Zero.
Use the sugar claim to answer a sugar question; check caffeine separately on the exact product.
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Overlooking sugar in a smaller can
Red Bull UK lists 27g sugars in a 250ml Original can. The NHS adult limit of 30g a day concerns free sugars, which are not automatically the same measure as total sugars on a drink label.
Read the per-can sugar figure and consider other sugary food and drinks you plan to have that day.
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Treating all energy-named drinks as interchangeable
Lucozade describes Energy as a sparkling glucose-drink range and identifies Alert separately as high caffeine. The range name alone does not establish the caffeine amount in an individual product.
Check the exact bottle’s ingredients, nutrition panel and caffeine declaration before substituting one drink for another.
Brand and range references
These examples show why the exact variant matters; a brand name alone does not establish sugar, caffeine or carbonation.
Red Bull
The UK Original and Zero product pages give figures for 250ml cans.
- Red Bull UK lists 80mg caffeine and 27g sugars for a 250ml Original can.
- Red Bull UK also lists 80mg caffeine for a 250ml Zero can and names sweeteners including sucralose, sodium cyclamate and sodium saccharin. Do not apply either variant’s full ingredient profile to the other.
Monster Energy
The UK Original Green and Monster Energy Zero Sugar pages describe different 500ml formulations.
- Monster Energy UK describes its 500ml Zero Sugar drink as carbonated and lists 160mg caffeine with 0g sugar.
- Its 500ml Original Green page lists 160mg caffeine and 55g sugar. Those figures belong to the named variants, not the entire Monster range.
Relentless
Guava is a flavoured, carbonated option containing sucrose, a sweetener and caffeine, according to Relentless.
- The Guava ingredient list explicitly names carbonated water and caffeine.
- Relentless says Guava is not recommended for children, people sensitive to caffeine, pregnant women or women who are nursing. Check the exact product and pack when shopping.
Lucozade
Lucozade describes Energy as a sparkling drink containing glucose and distinguishes it from its high-caffeine Alert range.
- The Energy range offers a sparkling glucose-drink route.
- Check the individual product’s caffeine declaration rather than treating the Energy and Alert ranges as equivalent.
Joybuy options for the weekly shop
These packs cover smaller sugar-free cans, larger zero-sugar and standard energy drinks, a flavoured energy drink and a sparkling Lucozade Energy option. Compare each named variant and its serving size before choosing a multipack.
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Red Bull Sugarfree Energy Drink, 4 × 250ml
For a weekly basket built around smaller sugar-free cans, this pack contains four 250ml drinks. Check the Sugarfree variant’s own label for its caffeine amount and warnings; figures for Red Bull Zero or Original should not be substituted for it.
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Monster Energy Ultra Zero Sugar, 4 × 500ml
This four-pack offers 500ml cans of the Ultra Zero Sugar variant. If the larger serving appeals, check its own caffeine declaration and warnings; specifications for Monster Energy Zero Sugar are not necessarily specifications for Ultra.
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Monster Energy Original Green, 9 × 500ml
Consider this nine-pack if you want the named standard 500ml variant rather than a zero-sugar one. Monster Energy UK lists 160mg caffeine and 55g sugar per 500ml Original Green can; account for the whole can when comparing it with smaller servings.
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Rockstar Blueberry & Pomegranate, 12 × 500ml
This twelve-can pack is a flavoured 500ml energy-drink option for stocking the weekly basket. Check caffeine, sugar and warnings on the exact can before comparing it with the other 500ml variants.
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Lucozade Energy Orange, 8 × 380ml
This eight-bottle pack represents the Lucozade Energy route rather than an assumption that all energy-named drinks share one formulation. Check the Orange bottle’s nutrition panel and caffeine declaration if you are comparing it with a high-caffeine can.
Questions before you buy
How do I compare caffeine in different can sizes?
Compare the mg stated for the whole can you expect to drink. Red Bull UK lists 80mg in a 250ml Original or Zero can, while Monster Energy UK lists 160mg in a 500ml Original Green or Monster Energy Zero Sugar can; check other variants individually.
Does zero sugar mean caffeine-free?
No. Monster Energy UK lists 0g sugar but 160mg caffeine per 500ml of Monster Energy Zero Sugar. Red Bull UK lists 80mg caffeine per 250ml of Red Bull Zero, so read both declarations on the variant you choose.
Is Lucozade Energy the same type of drink as a high-caffeine energy drink?
Do not assume so. Lucozade describes Energy as a sparkling drink containing glucose and presents its high-caffeine Alert range separately. Check the exact bottle’s nutrition panel and caffeine declaration before substituting one for another.
Can under-16s buy high-caffeine energy drinks?
Check the retailer’s current policy. Newcastle City Council says many national retailers already restrict sales to under-16s and reports that an England-wide ban is due to take effect in April 2027. That England position does not establish the rules for Scotland, Wales or Northern Ireland.
What if the drink is for someone who is pregnant or nursing?
Read the warning for the exact product rather than assuming it is suitable. Relentless says its Guava drink is not recommended for pregnant women or women who are nursing. For individual caffeine questions, ask a midwife, pharmacist or clinician.