A scroll through social media might have you worried that you’re missing a workout staple that’s seemingly as necessary as a proper-fitting sports bra and shoes: a pre-workout supplement, known colloquially as a pre-workout.
In fact, there are 4.3 million posts on Instagram with the hashtag “pre workout,” and the photos show you just how varied that term can be: There are chews, capsules, canned drinks, powders, and colorful liquid in shaker bottles all promising to help you get in a better workout.
It used to be that you ate a banana or piece of toast before a tough workout, and that was sufficient. But now it seems like every exerciser (at least on social media) is talking about pre-workout.
“If I want to get in a good workout, I need pre-workout.” “Oh my God! This workout is so hard. I can’t believe I forgot to take my pre-workout!” “Seriously, you don’t take pre-workout?”
As a trainer and regular exerciser, I’ve heard these lines from everyone. For the record, no, I don’t take a pre-workout supplement, nor do I recommend you take one either.
But since I know how often people talk about these supplements and how heavily marketed they’ve become, I decided to talk to sports dietitians to get their take. Turns out, while some pre-workouts may contain safe, energy-boosting ingredients, others can be pointless—or potentially harmful. Here’s what you need to know before joining the pre-workout faithfuls.
What is pre-workout?
A pre-workout is any supplement—usually a powder drink mix, but also available in the forms listed above—that claims to boost workout performance if you consume it beforehand.
First of all, it’s important to realize that virtually every supplement and exercise nutrition brand out there has its own pre-workout formula, meaning that no two tubs contain the same—or even similar—ingredients. In fact, according to a 2019 study of the top 100 commercially available pre-workout supplements, nearly half of all ingredients were part of a “proprietary blend,” meaning the amounts of each ingredient were not disclosed.
“There’s really no good definition of what a pre-workout supplement is—and a lot of companies are just slapping it on products because it’s ‘in’ right now—but in general, it’s a product that’s intended to boost energy levels, generally though a combination of B vitamins, carbs, and antioxidants,” registered dietitian Jessica Crandall, R.D.N., C.D.E., a spokesperson for the Academy of Nutrition and Dietetics, tells SELF.
While some pre-workout supplements have carbs, many are carb- and calorie-free. Others contain caffeine, beet juice, or amino acids such as arginine, citrulline, and ornithine, which companies market as revving up your “fight or flight” response, dilating your blood vessels, and increasing blood flow to your muscles, she says. Some supplements even contain esoteric ingredients like deer antler velvet to increase levels of insulin growth factor-1, a hormone that your body naturally produces in response to resistance training to increase muscle and tissue growth.
Why do people take pre-workout?
Most people take pre-workout for performance reasons or to simply feel better and less zonked when working out.
Pre-workout supplements have been studied on a bunch of workout metrics, including strength, power, and endurance, as well as time it takes to fatigue, and perception of effort—or how hard it feels like you’re working during a given task.
For those reasons, people may choose to take pre-workout before a variety of workouts, from trying to increase their one-rep max on the back squat, power through an interval-heavy running workout, or simply have enough gas left in the tank to crank out the final burpee in a HIIT class.
But does pre-workout actually do these things? It’s a mixed bag: Some pre-workout ingredients are well-studied and can actually help improve your performance, but the majority probably won’t—more on that below.
What are the benefits of pre-workout?
Carbohydrates, caffeine, beetroot juice, and creatine monohydrate (a popular muscle-building supplement) are all common pre-workout supplement ingredients that have been shown to improve exercise performance.
The reason carbs help is pretty obvious—they’re your body’s go-to source of energy and what experts recommend eating before a workout to properly fuel.
“Evidence supports a range of carbohydrate uses for various athletic applications, from taking in 30 to 60 grams per hour during endurance events to simply rinsing the mouth with a carbohydrate solution before sprint events,” Georgie Fear, R.D., CSSD, a board-certified sports dietitian with One by One Nutrition, tells SELF.
After all, when exercising—especially at high intensities with boot camps, indoor cycling classes, and lifting sessions—your body uses blood glucose and glycogen (stored carbs) as its main energy source. So topping off your levels before you start your workout can help increase energy availability and performance, she says.
Meanwhile, caffeine obviously is a stimulant known for boosting energy and alertness, and research shows it can help improve sports performance too. Many of the studies have been done on small sample sizes, but there’s actually a lot of research backing caffeine’s ability to improve workout performance. In fact, a 2020 review of 21 previously published meta-analyses on caffeine concluded that supplementation of it may enhance aerobic endurance, muscle strength, muscle endurance, jumping performance, and speed. Still, the authors caution that more research must be done on women and older individuals to make sure the results can be generalizable.
Beetroot juice is a little less researched, but a 2017 review on relevant studies found that it has consistently been shown to increase the body’s levels of nitric oxide—a natural vasodilator that expands blood vessels and increases blood flow—and improve cardiovascular performance. Plus, a 2020 study published in the International Journal of Sports Physiology and Performance found that people who took a beetroot supplement before a 30-second, all-out cycling sprint test produced more power and felt lower rates of perceived exertion than those who didn’t take the supplement. While it’s important to note that research on beets is still pretty young, and most studies are small, so far all of them show promising results
Lastly, creatine monohydrate is often included in pre-workout formulas. Creatine is a derivative of three amino acids that’s naturally produced in the body and stored in the muscles as a source of quick energy. While studies show supplementing with high doses does help build muscle mass and increase strength over time, “you can take creatine monohydrate pre-workout, post-workout, or at 8:49 P.M.,” Fear says. Some research even suggests that creatine monohydrate is actually more effective at boosting exercise performance if you take it after each workout as opposed to before—your body might be more apt to absorb and store it after workouts when your natural stores are at their lowest.
Even though you may have never heard of it, creatine is actually one of the most well-researched sports supplements over the past 20 years. These studies consistently show that in normal doses—three to five grams per day over the long term—it’s very safe for healthy adults. (It has also been linked to improved cognition, a decreased risk of depression, and a lower risk of heart disease.) The most common side effect is weight gained from water retention; when your muscles store creatine, they also store water. This can make your muscles look slightly bigger and weigh a bit more.
Gastrointestinal distress and muscle cramps can occur if you take too much at once or without being properly hydrated, but studies looking at daily creatine supplementation for up to a year have found no adverse effects. However, if you have diabetes, kidney problems, or any other major health condition, it’s best to talk with your doctor before regularly supplementing with creatine (or anything, really).
As for other supplement ingredients? “Most of the other ingredients in pre-workout supplements are unlikely to make a meaningful difference,” Fear says. “Trials that are funded by the supplement companies often find positive results for their product, which isn’t surprising, but unbiased trials show that if there is a performance benefit, it’s minimal.”
For example, one 2017 International Journal of Exercise Science study on 21 exercisers found that, compared with placebo, pre-workouts increase strength by a mere 4% to 8%, with the greatest benefits in those pre-workout supplements that contain caffeine. Another 2016 study on 31 exercisers from Oklahoma State University researchers found that when it comes to push-ups, commercially available pre-workout energy drinks provide no benefit compared with placebos.
What are the possible harms of taking pre-workout?
All workout-performance questions aside, safety is a big concern here since pre-workout supplements are not regulated by the FDA.
Like all supplements, pre-workout formulas are not regulated by the FDA for safety, so products can be stocked on shelves and sold until there’s a reason for the FDA to pull them (e.g., enough people report concerns). The only way to guarantee that a given product contains what it says it contains—and nothing it doesn’t—is to find a product that is certified through a third-party regulatory body such as NSF or Informed-Choice. Both of these organizations follow a strict vetting process to verify the quality and purity of supplements. Learn more about the guidelines here and here.
Meanwhile, some of the ingredients that are safe in normal amounts can become harmful in the high concentrations found in supplements. And again, since they’re not regulated, there’s no way to know if the concentration used was tested for various potential side effects.
For example, some people experience increased heart rate and blood pressure, diarrhea, nausea, and jitters when they consume high amounts of caffeine, Fear says. (It’s also possible to overdose, but it’s rare.)
While every person’s tolerance level is different, Crandall recommends avoiding any supplements that contain more than 100% of your recommended daily allowance of any one nutrient.
“At best, super-high doses of nutrients are buying you expensive urine, and at worst, they could contribute to the development of chronic diseases,” she says.
A 2017 study in the Journal of Clinical Oncology found that long-term supplementation with high doses of vitamin B6 and B12 may significantly increase the risk of lung cancer in men; other studies have connected excessive beta-carotene intake to cancer, and excess vitamin A to liver damage. Even ingesting too much caffeine at once can lead to potentially fatal cardiac issues, though it’s rare.
Basically, just because a nutrient is healthy in moderate amounts doesn’t mean it’s that much better in sky-high ones. And unless you have a doctor-diagnosed deficiency in any of these nutrients that you can’t fill with food alone, there’s no real need to supplement at all.
What else should you know before taking pre-workout?
For the ingredients that do show a performance benefit, there’s another way to get them: real food. And in this case, if you’re eating whole foods, you’ll know exactly what you’re getting.
“We have to stop thinking about nutrition as something that comes in a tub and start looking at our body’s natural fuel: food,” Crandall says.
She recommends fueling up for tough workouts with roughly 15 grams of carbohydrates—which you can get in half of a banana or one slice of bread with some jam. Experts also suggest eating a little bit of protein, but just a few grams, and keeping the fiber and fat to a minimum (both slow down digestion and can cause gastrointestinal discomfort while you’re exercising). If you’re into caffeine, a cup of coffee about 30 minutes prior to your workout will give you some extra energy.
Seriously, pre-workout nutrition can (and should!) be that easy. But if you want to try out pre-workout for yourself, you can give one of the options vetted by NSF or Informed-Choice a shot. (Make sure you stick to the serving size, and it’s always a good idea to check with your doctor about trying any new supplement, especially if you have any health conditions or take any medications.)
You might find pre-workout can help with an energy boost on the days you’re particularly dragging, which can give you the push you need to start your workout—just don’t expect it to make your 45-minute virtual HIIT class feel like a breeze.
Additional reporting by Christa Sgobba.