C4 Performance Energy has more caffeine than Starbucks Refreshers: 200mg vs 45mg in the same 16 oz can. That is a 155mg gap, and since the cans match, the per-serving number is the whole story.
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.
Starbucks Refreshers vs C4 Performance Energy: the numbers
| Starbucks Refreshers | C4 Performance Energy | |
|---|---|---|
| Caffeine per serving | 45mg per 16 oz grande | 200mg per 16 oz can |
| Caffeine per fl oz | 2.8mg | 12.5mg |
| Servings to reach 400mg (FDA context) | 8.9 | 2.0 |
Sources: Starbucks Refreshers's figure is verified in our Starbucks Refreshers caffeine guide against Starbucks nutrition listing (source); C4 Performance Energy's figure is verified in our C4 Performance Energy guide against Caffeine Informer (source).
The concentration gap is the striking part: C4 Performance 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 Starbucks Refreshers when you want the lighter dose or a slower ramp, and C4 Performance 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
- Starbucks Refreshers: the full caffeine guide
- C4 Performance Energy: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Starbucks Refreshers or C4 Performance Energy have more caffeine? C4 Performance Energy: 200mg per 16 oz can versus 45mg per 16 oz grande for Starbucks Refreshers.
Which is stronger per ounce? C4 Performance Energy, at about 12.5mg per fluid ounce versus 2.8mg for Starbucks Refreshers.
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