C4 Smart Energy has more caffeine than Red Bull on both counts: 200mg per 16 oz can against 80mg per 8.4 oz can, and about 12mg per fluid ounce against 10. The serving sizes differ, so the table below shows both ways of counting.
C4 Smart Energy vs Red Bull: the numbers
| C4 Smart Energy | Red Bull | |
|---|---|---|
| Caffeine per serving | 200mg per 16 oz can | 80mg per 8.4 oz can |
| Caffeine per fl oz | 12.5mg | 9.5mg |
| Servings to reach 400mg (FDA context) | 2.0 | 5.0 |
Sources: C4 Smart Energy's figure is verified in our C4 Smart Energy caffeine guide against Cellucor / 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 C4 Smart Energy 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
- C4 Smart Energy: 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
FAQ
Does C4 Smart Energy or Red Bull have more caffeine? C4 Smart Energy: 200mg per 16 oz can versus 80mg per 8.4 oz can for Red Bull.
Which is stronger per ounce? C4 Smart Energy, at about 12.5mg per fluid ounce versus 9.5mg for Red Bull.
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