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The short answer depends on what you want. The original Rockstar and the original green Monster are level on caffeine: 150 mg against 160 mg, in the same 500 ml can. The real difference is sugar. Rockstar has 62.5 g, close to 50 % more than Monster (42 g). Pick Monster if you want less sugar. Pick Rockstar if you want a drink sweetened with sugar only, with no sweetener.
Side by side
Figures for the 500 ml cans sold in Europe, taken from our original Rockstar and original green Monster pages, where each value links to its source. US cans can have different sizes and recipes: check the label of the can you actually buy.
| Rockstar | Monster | |
|---|---|---|
| Can size | 500 ml | 500 ml |
| Caffeine per can | 150 mg | 160 mg |
| Caffeine per 100 ml | 30 mg | 32 mg |
| Sugar per can | 62.5 g | 42 g |
| Sugar per 100 ml | 12.5 g | 8.4 g |
| Calories per can | 260 kcal | 185 kcal |
| Taurine per can | 100 mg | 2,000 mg |
| Sweetener | no | yes (sucralose, on top of sugar) |
| Sugar-free version | Original Zero Sugar: 150 mg, 0 g, 15 kcal | Zero Sugar: 160 mg, 0 g, 11 kcal |
No price here: we have no recent, sourced price for Rockstar, and a made-up one would skew the comparison.
What actually sets them apart
Caffeine: a 10 mg gap you won’t feel
Same can size, 150 mg against 160 mg: the gap is a little over 6 % of the dose. Both cans stay under the 200 mg single dose that EFSA considers safe for healthy adults. Caffeine is not a reason to pick one over the other.
Sugar: 20.5 g more in Rockstar
This is the gap that matters. 62.5 g of sugar in a Rockstar, 42 g in a Monster. Against the WHO ideal of under 25 g of free sugars a day, one Rockstar is two and a half times that amount, one Monster a little under twice. Rockstar also carries 75 kcal more (260 against 185).
Recipe: sucralose or not
The green Monster sold in France combines sugar and sucralose (ingredient list on Open Food Facts). Rockstar only has sugar. If you avoid sweeteners, that is the one clear point for Rockstar. Taurine differs a lot too: 100 mg declared for Rockstar, 2,000 mg for Monster.
Which one to pick
- If you watch sugar or calories, Monster, or better its Zero Sugar version.
- If you don’t want any sweetener, the original Rockstar, knowing it is the sweeter of the two.
- For the highest caffeine, Monster, though a 10 mg difference won’t be noticeable.
- If you want zero sugar without switching brands, both come in a sugar-free version with the same caffeine as the original (Rockstar Original Zero Sugar, Monster Zero Sugar). More options in our piece on sugar-free energy drinks.
For both, France’s food safety agency ANSES (page in French) advises against energy drinks before or during exercise, against mixing them with alcohol, and against them during pregnancy and for children and teenagers.
Where to buy
Amazon affiliate links: we earn a commission if you buy, at no extra cost to you. It does not change the comparison.
Frequently asked questions
Which has more caffeine, Rockstar or Monster?
Monster, barely: 160 mg against 150 mg per 500 ml can, or 32 mg against 30 mg per 100 ml.
Which one has more sugar?
The original Rockstar, with 62.5 g of sugar per can against 42 g for Monster, and 260 kcal against 185.
Can I drink two cans in a day?
Two Monsters make 320 mg of caffeine, two Rockstars 300 mg. That is under EFSA’s 400 mg a day for healthy adults, as long as you space them out (200 mg at most per dose) and count the day’s coffee or tea. The sugar goes well past the WHO target.
Read next
Sources
- Original Rockstar (caffeine, sugar, calories, taurine, ingredients): Open Food Facts.
- Monster caffeine and sugar: Monster Energy France official page; calories, taurine and ingredients: Open Food Facts.
- Caffeine guidance: EFSA. Precautions: ANSES. Free sugars: WHO.
