SAMHSAWhy are these drinks sending people to the emergency room? The only ingredient(s) in common energy drinks that have been proven to have acute stimulant effects are caffeine and guarana (which SAMHSA defines as "a plant product containing concentrated caffeine"). The vitamins and amino acids that many drinks include shouldn't give you a noticeable burst of energy unless you were previously malnourished and vitamin-deficient. And they're not reasoned to play a role in intoxication effects.
So, essentially, energy drinks can be looked at as caffeine. And as the SAMHSA report puts it, "Large amounts of caffeine can cause adverse effects such as insomnia, nervousness, headache, fast heartbeat, and seizures that are severe enough to require emergency care."
How much is a "large amount" of caffeine? Like alcohol, it's relative to metabolism and tolerance. Most people can tolerate a lot. In caffeine-modified electroconvulsive therapy, for patients with depression, up to 2,000 mg has been given -- intravenously. But that's in a controlled hospital environment where they are trying to give people seizures. And it does increase the likelihood they will have a seizure. For a frame of reference, SAMHSA notes, "The total amount of caffeine in a can or bottle of an energy drink varies from about 80 to more than 500 mg, compared with about 100 mg in a 5-ounce cup of coffee or 50 mg in a 12-ounce cola."
Those examples are a little misleading, though. The Center for Science in the Public Interest (CSPI) has a great list of how much caffeine specific foods/drinks contain. For energy drinks, "more than 500 mg" is far from the norm:
Center for Science in the Public InterestCran-Energy is a thing, yes.
And the 50 mg that SAMHSA cites for a "cup of coffee" is pretty optimistic -- at least in the way that many of us define coffee.
Center for Science in the Public InterestStill, despite the fact that a Starbucks venti coffee has three times as much listed caffeine as a can of Monster, some people swear they're more wired after drinking an energy drink. That may be because of the extra caffeine in guarana. Energy drinks can advertise that they have the same amount of caffeine as a cup of coffee; but when you include guarana, they have a much stronger stimulant effect. In Australia, listing quantified guarana content on beverages is mandatory.
The most interesting implication that the report mentions is from a study in which "bar patrons who consumed alcohol mixed with energy drinks were ... four times more likely to intend to drive while intoxicated." Because, as SAMHSA puts it, "Individuals, especially young drinkers, may incorrectly believe that consumption of caffeine can 'undo' the effects of alcohol intake and make it safe to drive after drinking."
That sort of stimulant-empowered bullheaded behavior -- rather than the E.R. admissions for caffeine-induced anxiety -- is actually the most pressing public health concern.
So, caffeinate responsibly. "If I drink another Hardcore Energize Bullet, am I going to have to go to the hospital again?"