Some mornings when you wake up early for an indoor cycling class, you're jazzed and ready to go. Other times, you need some extra incentive to get out the door, like seeing your friends in class or listening to your favorite workout playlist.
But if you could just drink a powder that makes you equally stoked to exercise and keeps you pumped up throughout the class, you probably would, right? Well, some people claim that taking "pre-workout" supplements can achieve this level of motivation and then some. But the question is, are these supplements a good idea? That depends on what's in the supplement.
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Many pre-workout supplements contain a similar blend of substances: caffeine, some form of creatine, and amino acid compounds. Taken together, people claim that these supplements give them more energy, increased endurance, and more of an overall "buzz" for a workout than they normally would possess. That makes sense, given what these individual ingredients do to the body.
Caffeine, for example, is a stimulant that targets the nervous system, heart, muscles, blood pressure, and provides energy, according to the American Council on Exercise (ACE). In studies on conditioned athletes, consuming caffeine before a workout has been shown to improve speed and stamina, as well as boost strength and power. But unlike a cup of coffee, which contains about 95 mg of caffeine, most pre-workout supplements contain 150-300 mg of caffeine per serving, which is a lot. For reference, the Dietary Guidelines for Americans suggest that people only have 400 mg of caffeine per day.
Then there's usually creatine, a chemical found in muscle tissue, foods like red meat and seafood, and the brain, according to MedlinePlus. Creatine basically provides energy for your muscles to do work. No surprise, then, that creatine has been shown to enhance people's muscular performance during short periods of high-intensity exercises, like sprinting or weightlifting, according to ACE. While creatine is safe to take short-term (most studies focus on the effects over about 30 days), it's not clear whether taking high doses of creatine daily could impact people's kidney and liver function long-term. Additionally, some people report stomach issues after taking creatine, so it's not for everyone.
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Finally, amino acids, the organic compounds that make up proteins, are another source of energy that you might find packed in a pre-workout supplement. There are nine "essential" amino acids that we get from food, a couple "nonessential" amino acids that our bodies produce naturally, as well as "conditional" amino acids, which aren't necessary unless you're ill, according to MedlinePlus. Arginine and alanine are conditional and nonessential amino acids respectively, that are often used in supplements as a way to get more protein. In truth, most people get enough protein through their diet alone, so packing on the extra amino acids isn't really necessary, according to MedlinePlus.
So, while the various substances that make up a packaged pre-workout supplement might sound intriguing, Courtney Dunn, MS, RD, CNSC, a dietitian in San Diego, says she still doesn't recommend pre-workout supplements. For starters, it's important to remember that the Food and Drug Administration doesn't regulate dietary supplements, so there's no telling what exactly is in supplement powders that you buy. Some of these powders contain excessive amounts of caffeine, which could affect your heart rate during cardio or high-intensity interval training, Dunn says.
Instead, Dunn suggests turning to food first for an energy boost before a workout, such as some coffee and a snack or meal with a complex carb and a whole food protein (chicken and quinoa, for example), two hours before working out. Or if you only have an hour before your workout, then a simple carb (like an apple) and protein shake would work, too, she says. "I recommend staying hydrated and eating consistently throughout the day to help keep energy levels up," she says. And if you find you need a boost during workouts, keep in mind that "regular exercise should also help with energy levels," she says.