C4 Smart Energy has more caffeine than Pepsi on both counts: 200mg per 16 oz can against 38mg per 12 oz can, and about 12mg per fluid ounce against 3. The serving sizes differ, so the table below shows both ways of counting.
These are different categories of drink, which changes how the caffeine arrives. Energy drinks and sodas list an exact number because caffeine is a measured additive; brewed drinks vary with the beans and the brew, so their figures are compiled averages. The numbers here are the standard published values for each.
C4 Smart Energy vs Pepsi: the numbers
| C4 Smart Energy | Pepsi | |
|---|---|---|
| Caffeine per serving | 200mg per 16 oz can | 38mg per 12 oz can |
| Caffeine per fl oz | 12.5mg | 3.2mg |
| Servings to reach 400mg (FDA context) | 2.0 | 10.5 |
Sources: C4 Smart Energy's figure is verified in our C4 Smart Energy caffeine guide against Cellucor / Caffeine Informer (source); Pepsi's figure is verified in our Pepsi guide against Caffeine Informer (source).
The concentration gap is the striking part: C4 Smart Energy packs roughly 4 times the caffeine per ounce. Sipping speed matters at that density; a 16 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Pepsi 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
- Pepsi: 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 Pepsi have more caffeine? C4 Smart Energy: 200mg per 16 oz can versus 38mg per 12 oz can for Pepsi.
Which is stronger per ounce? C4 Smart Energy, at about 12.5mg per fluid ounce versus 3.2mg for Pepsi.
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