What does pre-workout do and is it really effective? Know the caffeine-filled supplement’s health benefits — and risks — before buying.

With the fitness market expanding, more people are getting in on gym life and investing in things to kick their sessions up a notch. Enter pre-workout, a supplement mix that promises to boost energy, performance and focus. In 2023, the pre-workout supplement industry was worth an estimated $16.3 billion dollars, with wellness brands like Bloom and Peachy getting in on the game. It’s expected to only grow, and creators on social media — many of whom are young women — are fueling the hype.

Some say pre-workout allows them to plow through their high-intensity fitness routines, even when they’re initially feeling “meh” about exercising. “It’s coffee, but it’s coffee on steroids,” one fitness influencer said in a TikTok about her preferred pre-workouts. “It’s like a slap in the face of energy.” Another shared in a video that pre-workout makes her feel “super strong” to the point where she was “surprised” at how much she “wanted to push” herself.

The question, however, remains: Is pre-workout actually good for you? And can it help maximize your potential in the gym? Here’s what to know and why you should proceed with caution before jumping on this supplement bandwagon.

What is pre-workout?

Pre-workout is a dietary supplement “touted to boost energy when ingested before exercising,” Kathryn Wilson, a dietitian with Human Powered Health who specializes in sports nutrition, tells Yahoo Life. Typically, this supplement is a powder that you can mix into your choice of liquid, although sometimes it is a gel, capsule or premade drink.

There’s no one formula for pre-workout. The formulas all contain different combinations of supplements, but all are intended to do the same thing: boost your energy, stamina and power so you get the most out of your workout. The drinks are designed to be consumed a half hour to an hour before you get started. While anyone can take pre-workout; it’s particularly helpful for people who are doing long-lasting or high- intensity exercise and want the extra push.

What gives you this energy boost? For many pre-workout supplements, the answer is: mostly caffeine. Wilson says studies have shown that caffeine can “support perceived energy levels, endurance and strength performance, coordination and mental acuity during exercise.” These caffeinated powders are called “stim” (for stimulant) pre-workout powders, while ones without caffeine are “non-stim.”

Whether or not the powder contains caffeine, it typically also has a variety of other supplements that may (or may not) be backed by research to boost your workout performance.

Creatine, a highly researched supplement that helps increase muscle strength and boosts recovery, is one such supplement that is sometimes in pre-workout. Other potential ingredients include beta-alanine, amino acids or antioxidants, which manufacturers claim “will improve blood flow to the muscles and help control inflammation to improve exercise performance,” Wilson says. However, it’s important to note that supplements are not subject to pre-market review by the Food and Drug Administration (FDA).

Ashley Porterfield, a sports performance dietitian for the LA Galaxy, says when purchasing pre-workout, make sure it’s certified by reputable organizations, such as NSF Certified for Sport. This ensures that your mix was subjected to third-party testing and is free of banned substances. Such substances could pose a health risk, as well as be a problem should you be drug tested before a competition or while on a sports team.

What are the risks of pre-workout?

First, let’s talk about caffeine, which many of these “stim” pre-workouts contain a lot of.

“Most pre-workout products contain a dose of caffeine anywhere between 75 and 200 mg, which is the equivalent of about one to three cups of coffee,” Porterfield says.

Dietitian and exercise coach Catherine Gervacio says many of her patients are “surprised” when they hear how much caffeine is in pre-workout. While caffeine can certainly increase your energy temporarily, you are consuming a large quantity in a short amount of time, which Gervacio says can lead to symptoms like “jitters” and “a racing heart.” You may also struggle to sleep later on, which can affect your overall well-being — not to mention future athletic performance.

It’s also important to note that the FDA recommends that individuals ingest no more than 400 mg of caffeine per day in order to avoid unwanted symptoms, which also include irritability and headaches. But if your pre-workout is 200 mg of caffeine, you’re already halfway to your limit — and you’re not even including something like your morning coffee, a Diet Coke at lunchtime or any other caffeine throughout the day.

This is just the upper limit of caffeine — people who do not otherwise drink caffeine and therefore do not have a built-up tolerance may be more susceptible to side effects even with smaller quantities of caffeine.

What if your pre-workout doesn’t contain caffeine? There’s a wide range of ingredients in pre-workout, and not all may agree with you.

While creatine is one of the most studied supplements on the market and is, generally, considered safe, it can cause bloating and gastrointestinal upset, especially in large quantities. It’s also important to make sure that you aren’t supplementing with creatine separately if your pre-workout contains it, and that you are drinking enough water when taking creatine as it can cause dehydration.

Since there’s less FDA regulation with supplements, manufacturers can hide the exact amounts of key ingredients in pre-workout supplements by grouping them under “proprietary blends.” You may not know exactly how much of certain ingredients are in your pre-workout. That can be challenging, especially if you experience unwanted side effects — you may not know what supplement is specifically causing them.

On the flip side, you may also not know if there’s enough of a certain ingredient to make a big difference in your workout routine. A 2019 study found that many of these products list ingredients without revealing their quantities, and some were in amounts too small to be effective.

The bottom line

Pre-workout can theoretically give you a boost in the gym and may contain supportive ingredients that can aid in muscle building or recovery. However, you may not know for sure what you’re buying when you pick up pre-workout — and, if you go for the caffeinated variety, you need to be aware of how much you’re consuming.

The best way to support your workouts might be the simplest: Eat a balanced diet, get enough sleep and give yourself enough rest time so your body can recover from tough exercise.

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