Caffeine’s Dirty Little Secret

On Tuesday, curiosity finally got the best of me. How potent could Panera’s Charged Lemonades really be? Within minutes of my first sip of the hyper-caffeinated drink in its strawberry-lemon-mint flavor, I understood why memes have likened it to an illicit drug. My vision sharpened; sweat slicked my palms.

Laced with more caffeine than a typical energy drink, Panera’s Charged Lemonade has been implicated in two wrongful-death lawsuits since it was introduced in 2022. Though both customers who died had health issues that made them sensitive to caffeine, a third lawsuit this month alleges that the lemonade gave an otherwise healthy 27-year-old lasting heart problems. Following the second death, Panera denied that the drink was the cause, but in light of the lawsuits it has added warnings about the drink, reduced its caffeine content, and removed the option for customers to serve themselves.

All the attention on Panera’s Charged Lemonade has resurfaced an age-old question: How much caffeine is too much? You won’t find a simple answer anywhere. Caffeine consumption is widely considered to be beneficial because it mostly is—boosting alertness, productivity, and even mood. But there is a point when guzzling caffeine tips over into uncomfortable, possibly unhealthy territory. The problem is that defining this point in discrete terms is virtually impossible. In the era of extreme caffeine, this is a dangerous way to live.

Most people don’t have to worry about dying after drinking a Charged Lemonade. The effects, though uncomfortable, usually seem to be minor. After drinking half of mine, I was so wired that I couldn’t make sense of the thoughts ricocheting around my brain for the next few hours. Caffeine routinely leads to jitteriness, nervousness, sweating, insomnia, and rapid heartbeat. If mild, such symptoms can be well worth the benefits.

But consuming too much caffeine can have serious health impacts. High doses—more than 1,000 milligrams a day—can result in a state of intoxication known as caffeinism. The symptoms can be severe: People can “develop seizures and life-threatening irregularities of the heartbeat,” and some die, David Juurlink, a toxicology professor at the University of Toronto who also works at the Ontario Poison Centre, told me. “It’s one of the dirty little secrets, I’m afraid, of caffeine.” Juurlink said he occasionally gets calls about people, typically high-school or college students, who have ingested multiple caffeine pills on a dare or in a suicide attempt.

You’re unlikely to ingest that much caffeine from beverages alone, yet the increasing availability of highly caffeinated products makes it more of a possibility than ever before. Besides Panera’s Charged Lemonade, dozens of energy drinks contain similar amounts of caffeine, and some come in candy-inspired flavors such as Bubblicious and Sour Patch Kids. Less potent but highly snackable products include caffeinated coffee cubes, energy chews, marshmallows, mints, ice pops, and even vapes. Consumed quickly and in rapid succession, these foods can lead to potentially toxic caffeine intake “because your body hasn’t had time to tell you to stop,” Jennifer Temple, a professor at the University of Buffalo who studies caffeine use, told me.

More than ever, we need a way to track our caffeine consumption, but we don’t seem to have any good options. In all of the lawsuits against Panera, the basic argument is this: Had the company more adequately warned customers of the drink’s caffeine content, perhaps no one would have been hurt. But most of us just aren’t used to thinking about caffeine in numerical terms the way we do with calories and alcohol by volume (ABV). Caffeine intake is generally something that’s not measured but experienced: I know, for example, that a double espresso from the office coffee machine will give me the shakes. But even though I knew how much caffeine is in a Charged Lemonade, I had no idea how much of it I could drink before having the same reaction.

The FDA does have a recommended daily caffeine limit of 400 milligrams, the equivalent of about four or five cups of coffee. “Based on the relevant science and information available,” a spokesperson told me, consuming that much each day “does not raise safety concerns” for most adults, except for people who are pregnant or nursing, or have concerns related to their health conditions or the medication they take. The agency, however, doesn’t require food labels to note caffeine content, though some companies include that information voluntarily.

But the numbers are helpful only up to a point. The FDA’s daily recommendation is a “rough guideline” that can’t be used as a universal standard, because “it’s not safe for everybody,” Temple said. For one person, 237 milligrams could mean a trip to the hospital; for another, that would just be breakfast. The effect of a given caffeine dose “varies tremendously from person to person based upon their historical pattern of use and also their genetics,” Juurlink told me.

Although people generally aren’t aware of the amounts of caffeine they consume, they tend to develop a good sense of how much they can handle, Temple said. But usually, this knowledge is product-specific; when trying a new caffeine product, the effect can be hard to predict. Part of the problem is that the amount of caffeine in products varies dramatically, even among drinks that may seem similar: A 12-ounce Americano from McDonald’s contains 71 milligrams of caffeine, but the same drink at Starbucks contains 150 milligrams. The caffeine in popular energy drinks ranges from 75 milligrams (Ocean Spray Cran-Energy) to 316 milligrams (Redline Xtreme), according to the Center for Science in the Public Interest.

Contrast this with alcohol, which tends to be served in conventional units regardless of brand: a can of beer, a glass of wine, or a shot of liquor, all of which have roughly the same ability to intoxicate. Having a standard unit to gauge consumption isn’t foolproof—consuming too much alcohol is still far too easy—but it is nevertheless helpful for thinking about how much you’re ingesting, as well as the differences between beverages. Without such a metric for caffeine, consuming new beverages takes on a daredevil quality. Sipping the Charged Lemonade felt like venturing into the Wild West of caffeine.

The reason we aren’t good at thinking about caffeine is that historically, we’ve never really had to think that hard about it. Sure, one too many espressos might have occasionally put someone over the edge, but caffeine was consumed and sold in amounts that didn’t require as much thought or caution. “A generation ago, you didn’t have all these energy drinks,” so people didn’t grow up learning about safe caffeine consumption the way they may have done for alcohol, Darin Detwiler, a food-policy expert at Northeastern University, told me.

Compounding the concern is the fact that energy drinks are popular with kids, who are more susceptible to caffeine’s effects because they’re smaller. Kids tend to drink even more when drinks are labeled as highly caffeinated, Temple said, and the fact that they contain huge amounts of sugar to mask the bitter taste of caffeine adds to their appeal. Last year, a child reportedly went into cardiac arrest after drinking a can of Prime Energy—prompting Senator Chuck Schumer to call on the FDA to investigate its “eye-popping caffeine content.”

Nothing else in our daily diet is quite like caffeine. Certainly people swear by it, and its benefits are clear: Research shows that it can improve cognitive performance, speed up reaction time, and boost logical reasoning, and it may even reduce the risk of Parkinson’s, diabetes, liver disease, and cancer. But for a substance so ubiquitous that it’s called the most widely used drug in the world, our grasp of how to maximize its benefits is feeble at best. Even the most seasoned coffee drinkers sometimes unintentionally get too wired; as new, more highly caffeinated products become available, instances of caffeine drinkers overdoing it will probably become more common. Perhaps the best we can do is learn how much of each drink we can handle, one super-charged sip at a time.