Meet the experts: Yasi Ansari, M.S., R.D.N., C.S.S.D., is a spokesperson for the Academy of Nutrition and Dietetics. Steven K. Malin, Ph.D., is a fellow of the American College of Sports Medicine (FACSM) and associate professor of kinesiology and health at Rutgers-New Brunswick School of Arts and Sciences.

“These are basically dietary supplements that are purported to promote athletic performance, give more energy, improve focus, and enhance strength,” says Steven K. Malin, Ph.D., Fellow of the American College of Sports Medicine (FACSM), and associate professor of kinesiology and health at Rutgers-New Brunswick School of Arts and Sciences. They’re often in pre-made drinks or powder form that can be mixed with liquid.

The exact mix of ingredients varies widely between brands and products. Typically, pre-workouts will include a mix of caffeine, amino acids, creatine monohydrate, and B vitamins, says Ansari. According to one 2019 study that analyzed 100 of the top pre-workout supplements, common ingredients in these products include caffeine, beta-alanine, citrulline, tyrosine, taurine, and creatine.

If you’re a high-performance athlete, such as training for a marathon, there may be benefits. “Pre-workouts can support endurance training,” Ansari says. “Reported benefits include increased energy, alertness, improved power output, and decreased perceived exertion,” says Ansari. “However, it is not always needed, especially when someone is getting their needs met before [and] during training, and hydrating well throughout the day.”

Not all products are tested for safety and purity of ingredients. “It’s hard to know if what you see on the label is what you’re getting in the product,” says Ansari. You may find the term “proprietary blend” listed on pre-workout supplements. “I often note this as a red flag when educating clients because you are usually given undisclosed amounts of each ingredient under the proprietary blend,” Ansari says. “The problem with this is that you don’t know if you are getting too much or too little of an ingredient.”

In addition, there can be other health implications. “Because they are generally stimulants, anxiety and elevated heart rate/blood pressure could occur,” says Malin adding that dehydration and sleep disturbances are other possible side effects. People with heart conditions, anxiety, or other health conditions should be especially cautious.

You probably don’t “need” one. “Pre-workout supplements can be the icing on the cake after a solid nutrition foundation has been implemented,” says Ansari, meaning you should focus on getting the nutrients you need from food before turning to supplements. “This means eating regularly, getting enough overall nourishment, and adding variety to meals,” Ansari says, adding that including fiber, lean protein, healthy fat and a fruit or veggie at every meal is a good start.

“I don’t think it’s really needed,” Malin agrees, adding that caffeine alone (read: your daily coffee) is typically adequate. “There really aren’t good studies comparing these [products] and whether [they] do anything above and beyond that of caffeine.”

Caffeine is the most research-backed ingredient in pre-workouts. “Caffeine alone is arguably the most studied and consistently favorable on athletic performance,” says Malin. A good place to begin with caffeine is a starter dose of two to three milligrams per kilogram of bodyweight, says Ansari. That means a 150-pound person may need 136 to 204 mg of caffeine. A 12-oz cup of brewed coffee or two shots of espresso can help meet this goal.

Creatine also has science behind it, but it doesn’t matter if you have it before a workout or some other time: “Creatine helps, but not so much as a pre-workout concept, just overall in athletic gains for strength/power,” Ansari says.

Other ingredients, like citrulline and BCAAs, could be beneficial, but are less studied and/or have little data to support ergogenic (beneficial) effects, per Malin.

It’s not always easy to know. “Supplements are not FDA approved,” says Malin, adding that anabolic steroid derivatives have been found in certain products. He advises caution around supplements in general. “Talking with health professionals as well as looking for third-party certifications could help,” he says.

Examples of third-party testing agencies and certifications include NSF Certified for Sport and Informed Sport. “These types of certifications are recommended to ensure the safety, quality, and purity of the product and that the product contains what it states on the label,” says Ansari.

Also, avoid products that say they include a “proprietary” blend, per Ansari. “We do not know the exact amounts of each ingredient included in the supplement.”

“If you can meet needs through a foods-first approach, I’d recommend this to start,” says Ansari. “If you feel you need to add a pre-workout, consider speaking with a registered dietitian nutritionist (RDN) who specializes in sports nutrition. They can help ensure you’re not getting too much of any one ingredient and help you decide on a product that has been third-party tested and is best for you.” And if you do opt for trying one, be sure to choose a product with a third-party seal, such as NSF Certified for Sport, Ansari adds.

And remember, “you can absolutely use coffee as a pre-workout,” says Ansari, as long as you tolerate it well. Consume it within 60 minutes before exercise or during activity and closer to the time of fatigue for activities lasting longer than 60 minutes.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.