Mountain Dew Zero Sugar has more caffeine than Pepsi: 68mg vs 38mg in the same 12 oz can. That is a 30mg gap, and since the cans match, the per-serving number is the whole story.
Pepsi vs Mountain Dew Zero Sugar: the numbers
| Pepsi | Mountain Dew Zero Sugar | |
|---|---|---|
| Caffeine per serving | 38mg per 12 oz can | 68mg per 12 oz can |
| Caffeine per fl oz | 3.2mg | 5.7mg |
| Servings to reach 400mg (FDA context) | 10.5 | 5.9 |
Sources: Pepsi's figure is verified in our Pepsi caffeine guide against Caffeine Informer (source); Mountain Dew Zero Sugar's figure is verified in our Mountain Dew Zero Sugar guide against PepsiCo product facts (source).
Which one should you pick?
Pick Pepsi when you want the lighter dose or a slower ramp, and Mountain Dew Zero Sugar 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
- Pepsi: the full caffeine guide
- Mountain Dew Zero Sugar: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
FAQ
Does Pepsi or Mountain Dew Zero Sugar have more caffeine? Mountain Dew Zero Sugar: 68mg per 12 oz can versus 38mg per 12 oz can for Pepsi.
Which is stronger per ounce? Mountain Dew Zero Sugar, at about 5.7mg per fluid ounce versus 3.2mg for Pepsi.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.