Someday between my senior 12 months of school and now, I developed an inconveniently excessive caffeine tolerance, which means I’m at all times looking out for a drink that can make me really feel…one thing. So once I realized in regards to the new Starbucks Iced Power drinks, I used to be intrigued by the prospect of a beverage that simply may ship warmth reduction and an power increase in a single serving.

Combining “glowing fruit flavors with iced tea,” because the Starbucks web site reads, the corporate’s new Iced Power drinks look alluringly refreshing, however not like your common smoothie or slushie, they’re just about filled with caffeine. In keeping with the vitamin info obtainable on-line, the 24-ounce drinks comprise 140 to 205 milligrams (mg) of caffeine—on par with the shop’s grande, or 16-ounce, chilly brew. You’ve gotten three completely different choices to select from: Melon Burst Iced Power, Tropical Citrus Iced Power, and Frozen Tropical Citrus Iced Power with Strawberry Puree (that final one will be bought solely via the Starbucks app for a restricted period of time). The Tropical Citrus taste ideas the caffeine scales essentially the most, with 205 mg.

On a particularly sizzling New York day, I made a decision to strive one to keep off the afternoon droop. I ordered a Tropical Citrus Iced Power at a Starbucks a couple of minutes away from my workplace, and began sipping after lunch. By the point I used to be again at work, I had polished off a few quarter of it (which wasn’t exhausting to do, contemplating that it tasted like a fizzy iced tea). Whereas I used to be sitting at my desk about half an hour later, I seen that my focus had improved, my coronary heart was beating more durable, and my fingers shook once I tried to carry them nonetheless—and I nonetheless had half my Tropical Citrus Iced Power to go. Subsequent got here hassle focusing and a sense of stress in my head; my eyes appeared to skate over the Google doc on my laptop display. My physique’s response appeared to stabilize there, however my coronary heart charge nonetheless felt elevated once I left the workplace round 6:30 p.m.

So what was occurring there? For one, that drink flooded my physique with caffeine. The FDA recommends taking in not more than 400 milligrams per day, so one Tropical Citrus Iced Power packs simply over half of the each day max. (Plus, I used to be already about 100 mg deep since I additionally had espresso that morning.) That quantity places it properly above an 8.4-ounce Purple Bull (80 mg) and an eight-ounce cup of espresso (usually between 80 to 100 mg), however under a 20-ounce Charged Lemonade from Panera (259 to 260 mg). In keeping with the Related Press, Panera not too long ago introduced it will be pulling these drinks after a number of lawsuits had been filed in opposition to the corporate.

As somebody who usually drinks possibly two cups of espresso per day (three if I’m feeling particularly low-energy), I felt my response to the Iced Power was particularly pronounced—extra so than I anticipated, no less than. I assume it shouldn’t have been too shocking: Caffeine may cause a variety of results, particularly should you’re delicate to the stimulant: Suppose: heightened alertness, elevated urination, and an upset abdomen or heartburn. And should you absorb *too* a lot of it, you may expertise anxiousness, dehydration, dizziness, complications, and insomnia.