Rockstar XDurance has more caffeine than Prime Energy on both counts: 300mg per 16 oz can against 200mg per 12 oz can, and about 19mg per fluid ounce against 17. The serving sizes differ, so the table below shows both ways of counting.
Rockstar XDurance vs Prime Energy: the numbers
| Rockstar XDurance | Prime Energy | |
|---|---|---|
| Caffeine per serving | 300mg per 16 oz can | 200mg per 12 oz can |
| Caffeine per fl oz | 18.8mg | 16.7mg |
| Servings to reach 400mg (FDA context) | 1.3 | 2.0 |
Sources: Rockstar XDurance's figure is verified in our Rockstar XDurance caffeine guide against Rockstar product page / Caffeine Informer (source); Prime Energy's figure is verified in our Prime Energy guide against Caffeine Informer (source).
Which one should you pick?
Pick Prime Energy when you want the lighter dose or a slower ramp, and Rockstar XDurance 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 XDurance: the full caffeine guide
- Prime Energy: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Rockstar XDurance or Prime Energy have more caffeine? Rockstar XDurance: 300mg per 16 oz can versus 200mg per 12 oz can for Prime Energy.
Which is stronger per ounce? Rockstar XDurance, at about 18.8mg per fluid ounce versus 16.7mg for Prime Energy.
Barista Life runs on coffee people. Browse the Barista Life shop to support the site.