Guayaki Yerba Mate (can) has more caffeine than Starbucks Refreshers on both counts: 150mg per 15.5 oz can against 45mg per 16 oz grande, and about 10mg 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.
Guayaki Yerba Mate (can) vs Starbucks Refreshers: the numbers
| Guayaki Yerba Mate (can) | Starbucks Refreshers | |
|---|---|---|
| Caffeine per serving | 150mg per 15.5 oz can | 45mg per 16 oz grande |
| Caffeine per fl oz | 9.7mg | 2.8mg |
| Servings to reach 400mg (FDA context) | 2.7 | 8.9 |
Sources: Guayaki Yerba Mate (can)'s figure is verified in our Guayaki Yerba Mate (can) caffeine guide against Guayaki product page (source); Starbucks Refreshers's figure is verified in our Starbucks Refreshers guide against Starbucks nutrition listing (source).
The concentration gap is the striking part: Guayaki Yerba Mate (can) packs roughly 3 times the caffeine per ounce. Sipping speed matters at that density; a 15.5 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 Guayaki Yerba Mate (can) 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
- Guayaki Yerba Mate (can): the full caffeine guide
- Starbucks Refreshers: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Guayaki Yerba Mate (can) or Starbucks Refreshers have more caffeine? Guayaki Yerba Mate (can): 150mg per 15.5 oz can versus 45mg per 16 oz grande for Starbucks Refreshers.
Which is stronger per ounce? Guayaki Yerba Mate (can), at about 9.7mg per fluid ounce versus 2.8mg for Starbucks Refreshers.
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