An expert explains the real dangers of caffeine overdose if you drink too much coffee.

By Kristine Thomason
Updated January 08, 2020
Credit: Getty Images

Have you ever joked that you need a coffee IV? Well, the aptly named “Asskicker” from a café in Adelaide, Australia, comes pretty close.

Viscous Coffee is serving up an insanely powerful beverage made up of four shots of espresso, 120 ml of 10-day brewed cold drip, and eight 48-hour cold drip ice cubes. One Asskicker contains as much caffeine as about 80 shots of espresso (yes, 80!), according a report in the Adelaide Advertiser.

Café owner Steve Bennington said the Asskicker is meant to be sipped slowly over several hours, and keep you alert for 12 to 18 hours. He originally developed the recipe to help an ER nurse stay awake for her night shift. “She consumed her drink over two days and it kept her up for almost three days—I toned it down a little after that and the ‘Asskicker’ was born,” he said.

As the turbocharged coffee made headlines around the world this week, we wondered, How much is too much caffeine? To learn more about the health risks of caffeine overdose, we spoke with Dana Hunnes, PhD, a senior dietician at UCLA Medical Center.

She pointed out that the FDA has said 400 mg of caffeine a day is safe for adults. (That's roughly four or five cups of coffee.) The Asskicker has 12 times that amount. No matter how high your coffee tolerance, that much caffeine can cause a range of health complications, says Hunnes—including heart symptoms, muscle tremors, insomnia, an upset stomach, and anxiety. Plus, “too much caffeine can increase blood pressure," she adds, "which can increase risk of heart attack or stroke.”

Assuming you're not guzzling dozens of cups a day, how can you tell if you’re overdoing it on caffeine? Hunnes says to watch for signs like difficulty falling asleep, jitteriness, irritability, and feeling "strung out."

However, she notes, if you're craving a pick-me-up, coffee is a far healthier choice than soda or energy drinks. After all, coffee generally contains just two ingredients: coffee beans and water. “Other energy drinks contain so many chemicals and additives that they are really chemistry experiments,” Hunnes says.

As for the Asskicker, Hunnes advises staying far, far away: “This level of caffeine in one beverage just seems to be bordering on dangerous, and even irresponsible to me,” she says.

If you ever find yourself at this now notorious Australian coffee shop, maybe stick with a cold brew.