Rockstar Pure Zero has more caffeine than Red Bull on both counts: 240mg per 16 oz can against 80mg per 8.4 oz can, and about 15mg per fluid ounce against 10. The serving sizes differ, so the table below shows both ways of counting.
Rockstar Pure Zero vs Red Bull: the numbers
| Rockstar Pure Zero | Red Bull | |
|---|---|---|
| Caffeine per serving | 240mg per 16 oz can | 80mg per 8.4 oz can |
| Caffeine per fl oz | 15.0mg | 9.5mg |
| Servings to reach 400mg (FDA context) | 1.7 | 5.0 |
Sources: Rockstar Pure Zero's figure is verified in our Rockstar Pure Zero caffeine guide against Caffeine Informer (source); Red Bull's figure is verified in our Red Bull guide against Red Bull label / Caffeine Informer (source).
Which one should you pick?
Pick Red Bull when you want the lighter dose or a slower ramp, and Rockstar Pure Zero when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.
For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.
Related reading
- Rockstar Pure Zero: the full caffeine guide
- Red Bull: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
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Gear from this guide
FAQ
Does Rockstar Pure Zero or Red Bull have more caffeine? Rockstar Pure Zero: 240mg per 16 oz can versus 80mg per 8.4 oz can for Red Bull.
Which is stronger per ounce? Rockstar Pure Zero, at about 15.0mg per fluid ounce versus 9.5mg for Red Bull.
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