Travellers who want a smaller can
A 250ml can is a defined portion to carry with train food. Tesco Groceries lists both regular and Sugar Free Red Bull in four-packs of this size; their stated caffeine concentration works out to 80mg per can.
Who is each format for?
Buyers checking sugar as well as caffeine
If listed sugars matter to your choice, compare the nutrition panels rather than the pack names alone. Tesco Groceries lists 0g sugars per 100ml for Red Bull Sugar Free, but its caffeine warning still states 32mg per 100ml.
Travellers considering larger containers
Tesco Groceries lists 500ml Monster and Relentless can multipacks alongside 380ml Lucozade Energy bottle multipacks. Compare the volume and caffeine in one container before deciding how many portions the pack offers for your journeys.
What should you check?
Start with the container you would open on the train, then compare its caffeine information, sugar label and the number of containers in the pack.
| Priority | What to check | Your needs |
|---|---|---|
| Caffeine per container | Read the caffeine concentration and container volume together. Tesco Groceries states 32mg per 100ml for both 250ml Red Bull variants, equivalent to 80mg per can; check other drinks on their own labels. | I would rather know the caffeine in the whole can I plan to drink, not just the figure per 100ml. |
| Sugars and sweeteners | Compare sugars per 100ml and read the ingredients. Tesco Groceries lists 11g sugars per 100ml for regular Red Bull and 0g for Sugar Free, which lists sucralose and acesulfame K. Both variants state 32mg caffeine per 100ml. | If I choose a no-sugar formulation, I still want to check its caffeine and sweeteners separately. |
| Journey-sized portions | Check individual volume, container type, pack count and total volume. Tesco Groceries lists examples of 4 × 250ml cans, 4 × 500ml cans and 8 × 380ml bottles. | For a short journey, I may prefer a smaller can; for another trip, the bottle format or a larger container might suit how much I intend to drink. |
| Warnings and recipient | Read the warning on the specific drink. The Tesco Groceries Red Bull labels say these high-caffeine drinks are not recommended for children or pregnant or breast-feeding women. | When buying for someone else, I need to check whether the product warning applies to them before choosing a multipack. |
Common buying mistakes
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Comparing caffeine figures per 100ml alone
The amount in a full container also depends on its volume. NHS breastfeeding guidance gives 80mg as an example for a 250ml energy-drink can and notes that larger cans may contain up to 160mg; that is not a figure for every larger can.
Check the stated caffeine amount per container, or calculate it from the product’s concentration and volume, before switching sizes.
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Reading “sugar-free” as “caffeine-free”
Tesco Groceries lists 0g sugars per 100ml for Red Bull Sugar Free, alongside sweeteners and a high-caffeine warning of 32mg per 100ml.
Use the sugar and ingredient information for that part of the decision, then check caffeine and serving size independently.
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Counting containers without checking their size
Four 250ml cans, four 500ml cans and eight 380ml bottles offer different amounts of drink and different individual portions, as the Tesco Groceries listings illustrate.
Compare total volume and the number of containers you would actually use on your journeys.
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Overlooking warnings when buying for someone else
The Tesco Groceries Red Bull labels say the drinks are not recommended for children or pregnant or breast-feeding women. The NHS advises considering caffeine from other food and drink during pregnancy and breastfeeding.
Read the particular product’s warning and consider its full-can caffeine amount alongside other sources of caffeine where relevant.
Brand and format references
These Tesco Groceries listings illustrate different pack formats; check the individual product label when comparing variants.
Red Bull
Tesco Groceries lists regular and Sugar Free four-packs of 250ml cans.
- Both listed variants state 32mg caffeine per 100ml, or 80mg per 250ml can.
- Regular lists 11g sugars per 100ml; Sugar Free lists 0g, but retains the same stated caffeine concentration and high-caffeine warning.
Monster
Tesco Groceries lists Monster Energy Drink, Zero Sugar and Ultra in 4 × 500ml multipacks.
- The listed cans provide a 500ml container option.
- Check the chosen variant’s nutrition panel and caffeine warning rather than assuming all Monster cans match another drink’s figures.
Relentless
Tesco Groceries lists Relentless Origin as a 4 × 500ml multipack.
- Its listed format provides four larger cans.
- Read its own label for caffeine, sugars and ingredients before comparing it with another 500ml drink.
Lucozade Energy
Tesco Groceries lists Original and Orange in 8 × 380ml bottle multipacks.
- The listed bottle format offers a different individual container from the cans above.
- Pack count alone does not make it comparable with 250ml or 500ml cans; check the selected bottle’s label for its contents.
Joybuy can multipacks
These Joybuy options are can multipacks in 250ml, 355ml and 500ml formats for comparing individual portions on a train journey.
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Red Bull Sugarfree Energy Drink, 4 × 250ml
The 250ml cans offer a defined individual portion for a journey. For this matching Sugar Free variant, Tesco Groceries lists 0g sugars and 32mg caffeine per 100ml, equivalent to 80mg caffeine per can; its high-caffeine warning still applies.
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Red Bull Energy Drink, 4 × 250ml
This regular variant provides four 250ml cans. Tesco Groceries lists 80mg caffeine per can and 11g sugars per 100ml; check its high-caffeine warning when choosing who the pack is for.
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CELSIUS Kiwi Guava, 12 × 355ml
The 355ml individual can sits between the 250ml and 500ml formats in this selection. If that portion suits your journey, check the can’s caffeine amount, ingredients and warning before choosing the twelve-pack.
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Monster Energy Ultra Zero Sugar, 4 × 500ml
Each can is 500ml, so this pack is an option when you intend to take a larger individual container. Check the selected can’s caffeine amount per full serving and its nutrition panel rather than comparing its size or Zero Sugar name alone.
Frequently asked questions
Does a sugar-free energy drink contain caffeine?
It can. Tesco Groceries lists 0g sugars per 100ml for its Red Bull Sugar Free 4 × 250ml pack, but the same product states 32mg caffeine per 100ml. Check the sugar panel and caffeine warning separately on any variant you choose.
How much caffeine is in a 250ml energy-drink can?
It varies by product. Tesco Groceries states 32mg per 100ml for its regular and Sugar Free 250ml Red Bull cans, which is 80mg per can. Read another brand’s label rather than applying that figure to every 250ml drink.
What should I check if I am pregnant?
Check the product warning and caffeine from the whole day. The NHS advises no more than 200mg caffeine a day during pregnancy and identifies energy drinks, tea, coffee, cola, chocolate and some supplements as possible sources. The Tesco Groceries Red Bull labels say those products are not recommended for pregnant women.
What should I check if I am breastfeeding?
Check the product warning and your total caffeine intake. NHS breastfeeding guidance advises trying not to exceed 300mg caffeine a day if you drink it, and gives 80mg as an example for a 250ml energy-drink can. The Tesco Groceries Red Bull labels say those drinks are not recommended for breast-feeding women.
Will high-caffeine energy drinks be sold to under-16s in England?
The Department of Health and Social Care and Department for Education announced an England-specific ban on sales to under-16s from April 2027 for drinks other than tea or coffee containing more than 150mg caffeine per litre. It is a forthcoming restriction, not a UK-wide rule; check the applicable rules and product label at the time of purchase.