ZOA carries more total caffeine per serving (160mg per 12 oz can vs 120mg per 6.5 oz can), but ounce for ounce Starbucks Doubleshot Espresso & Cream is actually the stronger drink at about 18mg per fluid ounce against 13. Which one "has more caffeine" depends on whether you measure the container or the concentration.
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.
ZOA vs Starbucks Doubleshot Espresso & Cream: the numbers
| ZOA | Starbucks Doubleshot Espresso & Cream | |
|---|---|---|
| Caffeine per serving | 160mg per 12 oz can | 120mg per 6.5 oz can |
| Caffeine per fl oz | 13.3mg | 18.5mg |
| Servings to reach 400mg (FDA context) | 2.5 | 3.3 |
Sources: ZOA's figure is verified in our ZOA caffeine guide against ZOA FAQ (source); Starbucks Doubleshot Espresso & Cream's figure is verified in our Starbucks Doubleshot Espresso & Cream guide against Caffeine Informer / Starbucks nutrition (source).
Which one should you pick?
Pick Starbucks Doubleshot Espresso & Cream when you want the lighter dose or a slower ramp, and ZOA 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
- ZOA: the full caffeine guide
- Starbucks Doubleshot Espresso & Cream: the full caffeine guide
- The verified caffeine database
FAQ
Does ZOA or Starbucks Doubleshot Espresso & Cream have more caffeine? ZOA: 160mg per 12 oz can versus 120mg per 6.5 oz can for Starbucks Doubleshot Espresso & Cream.
Which is stronger per ounce? Starbucks Doubleshot Espresso & Cream, at about 18.5mg per fluid ounce versus 13.3mg for ZOA.
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.