Shoppers comparing sugar and calories
If a diet or zero-sugar drink is on your first shopping list, compare sugars and energy for the whole can. A front-of-pack name alone does not give you both figures.
Who is this choice for?
Shoppers choosing a smaller can
A 250ml can may suit you if you want the 80mg per-can caffeine amount listed for Red Bull Sugarfree by Red Bull UK or for Lucozade Alert Zero Sugar Mango Peachade by Tesco. Monster Energy UK lists 150mg or 160mg for its specified 500ml zero-sugar products.
Households checking caffeine warnings
Read the warning on the particular can before buying for a household. Sainsbury’s lists Lucozade Alert Zero Sugar Mango Peachade as not recommended for children, pregnant or breast-feeding women, or people sensitive to caffeine. Sale rules also depend on where and when you shop.
What should you compare?
Start with the figures for one complete can, then decide whether its size and the number of cans in the pack suit your first shop.
| Priority | What to check | Your needs |
|---|---|---|
| Sugars and energy | Read sugars and energy in kcal on the nutrition panel. Check whether the figures are per 100ml or per can, and compare the same serving basis. | I want to know what is in the can I will drink, rather than choosing by a diet or zero-sugar name alone. |
| Caffeine | Find caffeine in mg for the whole can and note its volume. Red Bull UK lists 80mg per 250ml Red Bull Sugarfree can; Monster Energy UK lists 150mg per 500ml Ultra can and 160mg per 500ml Zero Sugar can. | A smaller stated caffeine serving matters to me, so I would compare 250ml and 500ml cans before choosing. |
| Can and pack size | Check the volume of each can and the number of cans in the multipack. A pack containing more cans is a separate decision from the amount in each serving. | I am stocking a first food shop and want a quantity I expect to use, without mistaking a larger can for an equivalent serving. |
| Warnings | Read the current can’s caffeine warning and ingredients. If shopping for someone under 16, check the current rules in the nation where the purchase takes place. | Someone in my household may need me to check the product warning before I add an energy drink to the basket. |
Common buying mistakes
-
Reading zero sugar as caffeine-free
Zero-sugar products can still contain substantially different amounts of caffeine per can. Red Bull UK lists 80mg for a 250ml Red Bull Sugarfree can, while Monster Energy UK lists 150mg for a 500ml Ultra can and 160mg for a 500ml Zero Sugar can.
Read the caffeine figure for the complete can alongside the sugar information.
-
Comparing multipacks without checking the cans
A 500ml can contains twice the drink volume of a 250ml can; pack counts alone do not show how much is in one serving.
Check both the can volume and the number of cans, then compare nutrition and caffeine on a consistent basis.
-
Treating a planned England rule as a current UK-wide rule
The Department of Health and Social Care and Department for Education announced an under-16 sales ban for high-caffeine energy drinks in England intended for April 2027, subject to Parliamentary approval. That announcement does not establish a current rule across every UK nation.
Check the current position where you shop rather than assuming the planned England date or a retailer’s checkout practice applies everywhere.
-
Using an older listing instead of the can label
Ingredients, nutrition details and warnings on a listing may differ from those on the can being purchased.
Use listings to make a shortlist, then read the current can for sugars, energy, caffeine, ingredients and warnings.
Brand and product references
These figures describe the named products and can sizes, not every drink sold under each brand.
Red Bull
Red Bull Sugarfree is a 250ml option when a stated per-can caffeine amount matters.
- Red Bull UK states 80mg caffeine per 250ml Sugarfree can.
- Sugarfree does not mean caffeine-free; check the current label for the remaining nutrition and ingredient details.
Monster Energy
The named 500ml zero-sugar products are larger-can alternatives to the 250ml examples.
- Monster Energy UK lists 150mg caffeine for a 500ml Ultra can and 160mg for a 500ml Zero Sugar can.
- Compare the exact variant and its whole-can figures; the two Monster products do not have the same stated caffeine amount.
Lucozade
Lucozade Alert Zero Sugar Mango Peachade provides a 250ml example with grocery-listed energy and caffeine figures.
- Tesco lists 6 kcal and 80mg caffeine per 250ml can.
- Sainsbury’s lists a warning that this product is not recommended for children, pregnant or breast-feeding women, or people sensitive to caffeine.
Relentless
Relentless lists energy drinks in its UK product range.
- Check the nutrition and caffeine details of a specific can before comparing it with the named zero-sugar products.
Joybuy product options
These packs offer different can sizes and quantities to consider for a first food shop. Check the current label of the exact product for sugars, energy, caffeine and warnings before deciding.
Image unavailable
Monster Energy Green Zero Sugar, 12 cans
This 12-can pack is a larger-quantity choice for a first shop. Check the volume, sugars and caffeine shown on the individual can before comparing it with smaller packs.
Image unavailable
Red Bull Sugarfree Energy Drink, 4 × 250ml
This four-can pack offers a smaller can format. Red Bull UK states 80mg caffeine per 250ml Sugarfree can; check the current can label if its energy, ingredients or warnings affect your choice.
Image unavailable
Red Bull Zero, 4 × 250ml
The four 250ml cans offer a smaller-pack option. Read this variant’s own label for sugars, energy and caffeine rather than applying figures for Red Bull Sugarfree to Red Bull Zero.
Image unavailable
Monster Energy Ultra Zero Sugar, 6 × 4 × 500ml
This pack contains six groups of four 500ml cans, so consider both the serving size and the quantity. Monster Energy UK lists 150mg caffeine for a 500ml Ultra can; check the exact cans’ labels before purchase.
Image unavailable
CELSIUS Watermelon Strawberry, 12 × 355ml
The 355ml cans sit between the 250ml and 500ml formats shown here, while the pack contains 12 cans. Check this drink’s own label for sugars, energy, caffeine and warnings before comparing it with zero-sugar-labelled options.
Questions about zero-sugar energy drinks
Does zero sugar mean caffeine-free?
No. Red Bull UK lists 80mg caffeine per 250ml Red Bull Sugarfree can, and Monster Energy UK lists 150mg per 500ml Ultra can and 160mg per 500ml Zero Sugar can. Read the caffeine amount for the whole can separately from its sugar claim.
Should I choose a 250ml or 500ml can?
Choose by the amount in the complete can, not volume alone. For the named products, Red Bull UK and Tesco each list an 80mg caffeine serving in a 250ml can, while Monster Energy UK lists 150mg or 160mg in its specified 500ml zero-sugar cans. Check which serving and pack quantity suit your shop.
Is an under-16 energy-drink sales ban already in force across the UK?
The Department of Health and Social Care and Department for Education announced a ban on sales of high-caffeine energy drinks to under-16s in England intended for April 2027, subject to Parliamentary approval. As at October 2026, do not treat that planned England measure as an existing UK-wide rule; check the current position where you shop.
What if someone in the household is sensitive to caffeine?
Do not assume a zero-sugar label settles suitability. Sainsbury’s lists Lucozade Alert Zero Sugar Mango Peachade as not recommended for people sensitive to caffeine, children, or pregnant or breast-feeding women. Read the warning on the particular can before buying it for someone else.