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Michael: Have you ever glanced at the nutrition label on your favorite energy drink and wondered, “what the heck is actually in here?” And especially, what’s this taurine stuff? Researchers do think taurine plays an important role in human health. But even though companies stick it in energy drinks, we’re not sure if all that extra taurine actually does anything.

Taurine got its name back in the 1820s from the Latin taurus, which means ox or bull, probably because it was first isolated from ox bile – the fat-digesting stuff secreted by the liver. That might be how those rumors that Red Bull contains bull semen got started. It, um, definitely doesn’t, by the way.

Taurine’s chemical name is 2-aminoethanesulfonic acid [2-uh-meen-oh-eth-ane-sull-fawn-ic acid], but you might just see it called an amino acid. And it is an organic molecule that contains an amino group – a nitrogen atom bonded to three hydrogen atoms. But it doesn’t have a carboxyl group like the 20 standard amino acids you might’ve learned in chemistry class, and it isn’t actually a building block of proteins. Our bodies can usually make taurine, but you can also get it from eating things like meat and fish, or from supplements. It’s also found naturally in human breast milk.

There are taurine molecules in your brain, heart, skeletal muscle tissue, and bile. Scientists think taurine helps with fluid balancing, proper skeletal development, and healthy functioning of the central nervous and cardiovascular systems. It also could act as an antioxidant, helping to protect cells from damage caused by these super reactive atoms or molecules called free radicals.

When some research suggested that muscles might release taurine during exercise, people started thinking it might be a good exercise supplement... and eventually, an ingredient in energy drinks. But here’s where it gets tricky. Most of the studies on taurine in energy drinks are really limited – with 20 participants or fewer, focusing on Red Bull, and producing mixed results.

Some people showed very slight increases in endurance, alertness, or thinking ability, while others showed no difference at all. And the thing is, these energy drinks often contain a whole lot of caffeine, B vitamins, sugar, and other stuff, which affect the brain and body in their own ways. With all those other energy-boosting ingredients, it’s hard to tell whether taurine is adding much.

Pretty much everyone, including the International Society of Sports Nutrition, says we need more research to really figure out what taurine actually does, because there’s no solid evidence that it significantly affects energy levels. Either way, the amount of taurine in energy drinks seems to be safe for most people, so there’s no real harm in having it as an ingredient.

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