Learn how the most popular ingredients in these supplements affect your body — and your workout.
Pre-workout supplements have long been viewed as dietary add-ons that are beneficial solely for elite athletes. But in reality, people of all fitness levels could see a performance boost from these products, says Laura Kunces, Ph.D., R.D., the vice president of medical strategy at Thorne, an Equinox Circle partner.
The exact ingredients used vary significantly between pre-workout supplements, and their specific quantities are often undisclosed, instead being listed as components of “proprietary blends,” according to a 2019 Nutrients article. Most commonly, however, these supplements contain caffeine, creatine, and other amino acids such as beta-alanine, citrulline, tyrosine, and taurine, per the study. You’ll generally find carbohydrates and specific vitamins and minerals in pre-workout supplements, too, says Kunces.
How a pre-workout supplement affects your body — and, in turn, your performance in the Club — depends on what ingredients you’re consuming, in what combination and amount, and at what time, says Kunces. But a large body of research suggests that, in the short term, consuming multi-ingredient pre-workout supplements before exercise may have a positive effect on muscular endurance and subjective mood. Chronic consumption — when combined with a periodized resistance training program — may increase lean mass gains, according to a 2018 review published in the Journal of the International Society of Sports Nutrition (JISSN).
Here’s how they work — and what to know before you add one to your regimen.
How Pre-Workout Supplements Impact Performance
Ingredients like beta-alanine may play a role in that endurance boost. The amino acid minimizes neuromuscular fatigue, improves muscle stimulation and contraction, and increases levels of carnosine (a substance that has pH-buffering and anti-inflammatory effects) in muscle, research suggests. Early studies found that beta-alanine supplementation reduced fatigue when participants performed five sets of 30 max knee extensions, and it significantly improved isometric endurance after four weeks of use. But researchers say more studies are needed to understand just how long this fatigue-fighting effect lasts.
There’s also creatine, which is often included in pre-workout supplements since its uptake is best when your muscles are receiving a lot of blood flow, such as during exercise, says Kunces. It’s viewed by the International Society of Sports Nutrition as an effective ergogenic nutritional supplement for athletes to increase high-intensity exercise capacity and lean body mass during training.
Plus, pre-workout supplements can supply the carb-rich fuel needed to move — especially if you can’t stomach eating a full meal before your early morning workout, says Kunces. “It’s providing something to your body so that it's not breaking down some of the stores that it already has, either glycogen stores or amino acid stores,” she says. When created with amino acids, these products can also help jumpstart the recovery process once your workout ends, she adds.
In some products, added caffeine — a stimulant shown to minimize fatigue — and B vitamins enhance the energy boost, says Kunces. “B vitamins are used for producing energy in the body and can help turn food into fuel,” she explains. “There are other things too that will help create ATP in the muscle, which is your muscles’ energy source.” That includes creatine, which is used to facilitate quick movements, and patented ingredients like nicotinamide riboside (a unique form of vitamin B3), which supports energy metabolism, says Kunces.
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Combined, the stimulating ingredients in a pre-workout supplement may offer a mental boost, says Kunces. “Some people take pre-workouts for mental support during a workout, [maybe] they’re feeling drained or feeling fatigued or even being stressed,” she says. “...I think that cognitive part of pre-workouts is just so undervalued. There's so much about a workout that requires your brain capacity, like reaction time, hand-eye coordination, and memory, problem-solving, that is really important to hone in on for people who are seeking that kind of support. A pre-workout could be really beneficial in that case.”
Exhibit A: In a 2024 study of 20 resistance-trained participants, researchers found that consuming a multi-ingredient pre-workout supplement an hour before an upper-body workout resulted in improved reaction time and reduced overall session rating of perceived exertion when compared with a placebo.
Pre-Workout Risks and Side Effects
Though there is evidence to suggest pre-workout supplements can have a positive effect on your performance, there have historically been mixed results regarding their effect on force and power production, according to the JISSN review. The effects of long-term supplementation on force production, muscular endurance, aerobic performance, and subjective measures are also unclear, per the review.
Another uncertainty: Just how safe it is to consume pre-workout supplements in the long run. Research currently available has found them to be relatively safe to consume for less than eight weeks, but more information is needed to determine long-term safety, according to the JISSN review.
That’s part of the reason why Kunces advises everyone to chat with their healthcare provider about using pre-workout supplements before taking one. This is especially important for folks taking medication, kids and teenagers, pregnant individuals, and people with other health conditions.
After getting the all-clear, look for a high-quality pre-workout supplement that is third-party tested and is NSF Certified for Sport, Kunces suggests. “That way you know that the ingredients are what they say they are on the label and that they've been tested, so they're free of banned substances or free of things that you perhaps should not be taking,” she says. (For the record, the U.S. Food and Drug Administration does not approve dietary supplements for safety or effectiveness or approve their labeling before they’re sold, and it’s up to the companies to ensure their products meet safety standards.)
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While taking a pre-workout supplement, you might experience side effects such as jitters and GI upset related to the caffeine, says Kunces. If that’s the case, look for a product that contains a small amount of the stimulant or is free of it. Powder pre-workouts that you mix with water might cause some stomach discomfort during your workout simply from downing so much fluid so quickly, she adds.
Importantly, look out for tingling, itching, and elevated heart rate; those are all signs to stop taking the supplement and chat with your healthcare provider about other options, says Kunces.
How to Safely Use Pre-Workout Supplements
Once you’ve found a pre-workout supplement that’s designed to support the workout you’re performing, stick with the product’s consumption directions. Since the ingredients and their quantities vary between products, there’s no overarching rule for when to use your supplement. “Most carbohydrates can be pretty fast-acting, but there are some that are a little bit more slow-acting,” says Kunces. “Caffeine might be something you want 30 to 60 minutes before a workout, while Thorne has a beta-alanine [supplement] that is a sustained release.”
In other words, take the supplement at the times suggested on the product label, and don’t consume more than the recommended serving. “Some people think more is better, like, ‘Oh, if I have one scoop, that's good, so two scoops is better,’’ says Kunces. “That's not always the case.” In fact, it’s a good idea to start with half of a dose to see how your body reacts then slowly build up to the suggested serving, she adds.
As you incorporate the product into your regimen, keep the rest of your practice stable; don’t try taking a new pre-workout supplement before performing a new type of workout and recovery method. While these supplements can be beneficial for any type of athlete — from the occasional weightlifter to the dedicated bodybuilder — not every pre-workout is appropriate for every person, says Kunces. Spend time looking at ingredient labels and trialing products until you find a supplement that best supports your fitness journey.
Through Equinox Circle, you’ll receive exclusive access to Thorne’s curation of Equinox supplement bundles with preferred pricing and ongoing limited-time offers to help you in your pursuit of high performance