If you want a smaller stated caffeine amount in a single zero-sugar can, Red Bull says Sugarfree contains 80mg per 250ml, while Monster Energy says Ultra contains 150mg per 500ml. Choose by the amount in the whole container and the caffeine you consume from other sources; zero sugar does not mean caffeine-free, and sweeteners and product warnings still matter.
The useful comparison depends on whether sugar, the caffeine in one container or a warning on the label drives your choice.
If you want a drink to carry alongside a gym-bag snack without choosing a sugar-containing variety by mistake, compare sugars on the nutrition panel and read the sweetener ingredients. Check whether the figures are given per 100ml or per whole can.
If you also have coffee, tea or a pre-workout product, use the caffeine amount in the entire can when comparing a compact drink with a larger one. A zero-sugar claim tells you nothing about that amount.
If the drink is for a child, someone who is pregnant or breastfeeding, or someone sensitive to caffeine, read the warning on the exact product. Removing sugar does not remove caffeine or change a product-specific warning.
Start with sugars and ingredients, then compare caffeine per whole container and choose a format you intend to use. A larger can is not simply a longer-lasting version of a compact one when you plan to drink it all.
| Priority | What to check | Your needs |
|---|---|---|
| Sugars and sweeteners | Read sugars per 100ml and per container where shown. Check the ingredient list if a particular sweetener matters to you; a drink containing a sweetener can also contain sugar. | I want a zero-sugar option, but I also want to know which sweeteners it contains before putting it in my bag. |
| Caffeine per container | Sainsbury's lists 30mg caffeine per 100ml for its 250ml Gold Bolt Zero can, equivalent to 75mg per can. Red Bull states 80mg per 250ml Sugarfree can; Monster Energy states 150mg per 500ml Ultra can. Compare whole containers, not just concentrations. | When I have caffeine from other drinks or products, I need to know what one complete can would add to my total. |
| Size and use | Compare the stated 250ml and 500ml can sizes with how much you intend to drink. For a bottle you may open more than once, follow its own storage instructions. | A compact can fits what I plan to drink at one time; if I choose a larger format, I want to account for the full contents. |
| Warnings | Read the exact product's age, pregnancy and caffeine-sensitivity warnings. Sugar-free status does not change them. | If I am buying for someone covered by a warning, I need to check that warning rather than choosing on sugar content alone. |
Red Bull Sugarfree contains 80mg caffeine per 250ml can, according to Red Bull, while Monster Energy states that a 500ml Ultra can contains 150mg. The sugar claim does not tell you the caffeine amount.
Compare caffeine per whole can and include other caffeine-containing drinks or products you plan to have.
Relentless Energy lists both sucrose and sucralose in White Citrus. A sweetener in the ingredients is therefore not enough to identify a zero-sugar drink.
Check the sugars figure on the nutrition panel as well as the ingredient list.
A caffeine ingredient tells you that it is present, not how much you would drink in a serving or an entire bottle.
If the caffeine amount matters to your choice, check the current bottle label for a stated amount before using it to plan your intake.
These examples show why the exact variety and container matter. A brand or retailer name alone does not establish a drink's sugar content or caffeine amount.
Sugarfree is a compact-can reference for shoppers comparing a stated caffeine amount.
Ultra provides a 500ml zero-sugar can for comparison with smaller formats.
White Citrus illustrates why an energy drink with a sweetener should not automatically be treated as a diet variety.
Energy Zero Sugar Orange is a larger, 900ml bottle format rather than a single compact can.
Tesco is a retailer reference for comparing sugar-free energy-drink listings, not a single formulation.
Its own-label Gold Bolt Zero Sugar offers another 250ml can to compare by caffeine amount.
These Joybuy listings include compact Red Bull cans, a larger Monster Ultra can and two CELSIUS 355ml varieties. Compare the stated pack format with the sugar, caffeine and warning information on the exact product you choose.
No image available
A compact can for comparing a stated whole-can caffeine amount. Red Bull says Sugarfree contains 80mg caffeine per 250ml can; it is not a caffeine-free choice.
No image available
A 500ml can if you intend to choose a larger zero-sugar drink. Monster Energy states that Ultra contains 150mg caffeine per can, so compare the whole-can amount with any other caffeine you consume.
No image available
Another compact can format for the gym bag. Check the Zero variety's own caffeine figure, sweeteners and warning label rather than treating it as identical to Sugarfree.
No image available
The 355ml can sits between the compact and 500ml formats by container size. Compare its own sugars, caffeine per can and ingredient list before choosing it for a gym bag.
No image available
This is a separate 355ml flavour and pack. Check its own sugars and whole-can caffeine figure, along with its warnings, rather than assuming they match the Kiwi Guava variety.
No. Red Bull states that a 250ml Sugarfree can contains 80mg caffeine, and Monster Energy states that a 500ml Ultra can contains 150mg. Check caffeine per whole container separately from the sugar claim.
Use the whole-can amount to understand what you would consume if you finish it. A per-100ml figure helps you compare concentrations, but cans of different sizes can contain different total amounts. Include caffeine from other drinks and products when considering your total.
No. Relentless Energy lists both sucrose and sucralose in White Citrus. Read the sugars figure and ingredient list rather than relying on the presence of a sweetener.
No. An ingredient list can identify caffeine without stating how much is in a serving or the bottle. If the amount affects your choice, check the current label for a quantified caffeine figure.
Follow the warning on the exact product; choosing a zero-sugar variety does not remove it. Check the label before buying for a child or someone who is pregnant, breastfeeding or sensitive to caffeine.