When it comes to spending time in the gym, most of us will take any reasonable edge we can get. Anything that motivates us to get there in the first place, maximize our workout once we're there, or improve our results. In this effort, many people choose specific meal plans or learn techniques and strategies to better build muscle and burn calories.

But some people also look to dietary supplements for a boost. Such supplements may include individual powders or capsules, but many people take a so called "all-in-one" dietary supplement combination option known colloquially as pre-workouts. "The pre-workout drink and powder market has exploded in recent years with more and more products on the shelves," says Matthew Anastasi, MD, a consultant within the division of sports medicine department of orthopedics at Mayo Clinic in Arizona.

Knowing what these products are and whether or not they are safe to consume can be helpful. 

What are pre-workout supplements? 

Pre-workout supplements are powders, beverages, gummies or capsules that are marketed as being able to improve athletic performance. Various pre-workout brands contain various ingredients, advertised as working together to ward off fatigue and keep energy levels high throughout one's workout. These ingredients may include amino acids, protein, ashwagandha, calcium and creatine. Some also contain D and B vitamins, plus minerals such as sodium and potassium. Other pre-workout products offer "fluid, carbohydrates and electrolytes," says Leslie Bonci, MPH, RDN, a sports dietitian for the Kansas City Chiefs and founder of Active Eating Advice. Most brands contain a variety of any of the aforementioned ingredients and more. 

But perhaps the most desirable ingredient in the majority of pre-workout brands is the energy-boosting stimulant caffeine; "which is often included in very high amounts," says Uma Naidoo, MD, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital and the author of “Calm Your Mind with Food." Indeed, a single scoop of one of the most popular pre-workout brands (Onnit Alpha BRAIN Pre-Workout) packs 200mg of caffeine - half the maximum amount of caffeine the Centers for Disease Control and Prevention recommends staying under per day. 

What do pre-workouts do? 

That's not to say that all of the ingredients in pre-workouts are problematic. When taken within recommended daily doses, many pre-workout ingredients have proven health benefits. Vitamins, minerals, protein and amino acids, for instance, are certainly important parts of a healthy diet. 

And Bonci says some pre-workout supplements, "could be advantageous for endurance activities or exercise." Some ingredients may also "optimize strength, speed and stamina," and "provide an exogenous source of fuel so the body does not have to use protein as a fuel source during exercise," she says. The electrolytes in many pre-workouts can also help with hydration.

"For some people, taking pre-workouts may improve focus, concentration, and provide increased energy and better muscle building," echoes Naidoo.

Are pre-workout supplements safe?

But it's not all good news as some ingredients within pre-workouts are less studied, unsafe or included at levels that exceed the recommended daily allowance. This can occur because dietary supplements aren't regulated by the U.S. Food and Drug Administration the same way foods and drugs are. And no supplement can take the place of eating right. "I generally caution people on the safety of pre-workout supplements," says Naidoo. "While some of these supplements contain healthy vitamins and amino acids, many are also loaded with sugars and artificial sweeteners and an extreme amount of caffeine that can be detrimental to mental fitness and gut health."

Anastasi agrees and recommends for "everyone to pay close attention to what ingredients are actually in pre-workouts as they can vary greatly." In high doses, some ingredients within pre-workouts can cause digestive issues, high blood pressure and irregular heartbeat. Some ingredients can also offset individual work done to excel in athletic endeavors. "It is critical to test all pre-workout drinks and powders prior to using them before a big race or other competitive setting," he says.