Rockstar Original carries more total caffeine per serving (160mg per 16 oz can vs 120mg per 12 oz can), but ounce for ounce Zevia Energy is actually the stronger drink at about 10mg per fluid ounce against 10. Which one "has more caffeine" depends on whether you measure the container or the concentration.
Zevia Energy vs Rockstar Original: the numbers
| Zevia Energy | Rockstar Original | |
|---|---|---|
| Caffeine per serving | 120mg per 12 oz can | 160mg per 16 oz can |
| Caffeine per fl oz | 10.0mg | 10.0mg |
| Servings to reach 400mg (FDA context) | 3.3 | 2.5 |
Sources: Zevia Energy's figure is verified in our Zevia Energy caffeine guide against Zevia / Caffeine Informer (source); Rockstar Original's figure is verified in our Rockstar Original guide against Rockstar product page (source).
Which one should you pick?
Pick Zevia Energy when you want the lighter dose or a slower ramp, and Rockstar Original 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
- Zevia Energy: the full caffeine guide
- Rockstar Original: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Zevia Energy or Rockstar Original have more caffeine? Rockstar Original: 160mg per 16 oz can versus 120mg per 12 oz can for Zevia Energy.
Which is stronger per ounce? Zevia Energy, at about 10.0mg per fluid ounce versus 10.0mg for Rockstar Original.
Barista Life runs on coffee people. Browse the Barista Life shop to support the site.