Occasional caffeine buyers
If you are buying cans for planned daytime revision, compare the caffeine in a whole can with what you may consume from other sources. NHS Borders advises avoiding caffeine-containing drinks close to bedtime.
Who is this choice for?
Sugar-conscious shoppers
Red Bull describes Sugarfree as without sugar, and Monster states that Ultra has 0 g sugar per 500 ml can. Check caffeine separately: the manufacturers state 80 mg and 150 mg per can respectively.
Shoppers choosing a pack quantity
Compare the number of cans and their individual sizes with the revision sessions you have in mind. A larger pack changes how many cans you keep on hand, not the caffeine in each can.
What should you check before buying?
Start with the exact can’s caffeine and sugar declarations, then decide whether the pack quantity fits when you plan to drink it.
| Priority | What to check | Your needs |
|---|---|---|
| Caffeine per can | Read the milligrams for the whole can and its volume. Red Bull states 80 mg per 250 ml Sugarfree can; Monster states 150 mg per 500 ml Ultra can. Count caffeine from other sources too. | I want to know the amount in a can before deciding whether to open it during a study session. |
| Sugar | Read the sugar declaration on the exact drink, separately from its caffeine amount. Monster states 0 g sugar per 500 ml Ultra can; Lucozade says its Energy range contains glucose. | If I choose a sugar-free drink, I still need to check how much caffeine the can contains. |
| Timing | Check whether the drink contains caffeine and when you expect to finish it. NHS Borders advises avoiding caffeine-containing drinks close to bedtime because they can disrupt sleep. | For revision near bedtime, I would rather choose a non-caffeinated drink than plan around another can of caffeine. |
| Pack quantity | Compare can count and can volume; check the per-can declaration rather than treating a multipack as one serving. | A pack that covers a few planned sessions may suit me better than keeping more cans within reach. |
| Age conditions | Check the exact drink’s warning and the seller’s age policy. Sainsbury’s says it does not sell high-caffeine energy drinks to under-16s. GOV.UK announced an England sales ban for under-16s planned for April 2027; that is not a current UK-wide rule. | If I am buying for someone under 16, I need to check the retailer’s current conditions rather than assume every shop or UK nation has the same rule. |
Common buying mistakes
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Comparing packs without checking the dose in one can
Pack volume does not tell you the caffeine in a serving. Monster states 150 mg per 500 ml Ultra can, while Red Bull states 80 mg per 250 ml Sugarfree can.
Choose a per-can amount you intend to account for before comparing can counts.
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Keeping a large pack for late-night revision
NHS Borders advises that caffeine-containing drinks can make you feel more awake and disrupt sleep close to bedtime.
If you expect to study near bedtime, choose a non-caffeinated alternative rather than relying on another energy-drink can.
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Reading “sugar-free” as “low caffeine”
Monster states that Ultra contains 0 g sugar and 150 mg caffeine per 500 ml can. The two declarations answer different questions.
Check both figures on the exact drink you intend to buy.
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Assuming every energy drink has the same formulation
Lucozade describes its Energy range as containing glucose, unlike the sugar-free formulations described by Red Bull and Monster.
Compare the exact pack’s ingredients, sugar declaration and caffeine information instead of relying on the category name.
Brand and product-range references
These references describe particular drinks and formats; a brand name alone does not establish the contents of every can it sells.
Red Bull
Sugarfree is a 250 ml can option for shoppers who want to compare a smaller can with larger formats.
- Red Bull states that each 250 ml Sugarfree can contains 80 mg caffeine and is without sugar.
- Sugarfree still contains caffeine; check the quantity and timing of every can you plan to drink.
Monster
Ultra is a 500 ml zero-sugar can listed in multipack formats by UK grocery retailers.
- Monster states that a 500 ml Ultra can contains 0 g sugar and 150 mg caffeine.
- Its stated caffeine amount is for the whole 500 ml can, so do not compare it with a 250 ml can by pack count alone.
Lucozade
Lucozade Energy is a glucose-containing drink range; Tesco lists an Original 8 × 380 ml multipack.
- Lucozade says its Energy drinks contain glucose.
- Check the caffeine and sugar declarations on the exact multipack rather than treating it as interchangeable with a sugar-free can.
Relentless
Tesco and Sainsbury’s list Relentless Origin in a 4 × 500 ml format.
- The listed format makes can count and volume straightforward to compare.
- Read the exact pack’s caffeine and sugar declarations before comparing its formulation with another drink.
Joybuy multipack options
These cans offer different pack quantities, serving sizes and sugar declarations for shoppers considering an energy drink for planned revision sessions. Check the caffeine in each can and avoid caffeine close to bedtime if protecting sleep is the priority.
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Red Bull Sugarfree 12 × 250 ml
A 12-can sugar-free pack for shoppers comparing smaller individual cans. Red Bull states 80 mg caffeine per 250 ml Sugarfree can; it is not caffeine-free.
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Red Bull Sugarfree 24 × 250 ml
The same 250 ml Sugarfree can format in a larger, 24-can pack. Red Bull states 80 mg caffeine per can; consider whether you want to keep that many cans on hand.
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Red Bull Energy Drink 8 × 250 ml
An eight-pack of 250 ml cans for shoppers considering the sugar-containing version. The product information states 80 mg caffeine and 28 g sugars per can; this is not the Sugarfree variant.
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Monster Energy Ultra Zero Sugar 6 × 4 × 500 ml
This large multipack contains 500 ml zero-sugar cans. Monster states 150 mg caffeine per 500 ml Ultra can; the 6 × 4 format also means keeping a substantial quantity on hand.
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Rockstar Blueberry & Pomegranate 12 × 500 ml
A 12-pack of 500 ml cans with a stated 200 mg caffeine per can. Its product information reports 4.2 g sugars per 100 ml; check both declarations when comparing it with the other formats.
Questions about revision drinks
How do I compare caffeine across different can sizes?
Compare milligrams in the entire can, then account for caffeine from other sources that day. Red Bull states 80 mg per 250 ml Sugarfree can, while Monster states 150 mg per 500 ml Ultra can; comparing volume alone misses that difference.
Does sugar-free mean a better choice for late revision?
No: a sugar-free declaration does not tell you whether a drink suits your timing. Monster states that Ultra contains 0 g sugar and 150 mg caffeine per 500 ml can, and NHS Borders advises avoiding caffeine-containing drinks close to bedtime because they can disrupt sleep.
What if I revise close to bedtime?
Choose a non-caffeinated drink if protecting sleep is your priority. NHS Borders advises avoiding caffeine-containing drinks, including energy drinks, close to bedtime because they can make you feel more awake and disrupt sleep.
Can someone under 16 buy a high-caffeine energy drink?
Check the retailer and where the purchase takes place; there is no current UK-wide rule established by the announced England measure. Sainsbury’s says it does not sell high-caffeine energy drinks to under-16s. Separately, GOV.UK announced an England sales ban for under-16s planned for April 2027.