A complete guide on pre-workout - the energy-boosting supplement used by exercise enthusiasts and gym rats

A complete guide on pre-workout - the energy-boosting supplement used by exercise enthusiasts and gym rats
Drinking pre-workout before you hit the gym may give you a boost of energy.GoodLifeStudio/Getty images
  • Pre-workout supplements are intended to boost energy so you can work out harder and longer.
  • Taking pre-workout can cause side effects like nausea and shakiness due to high caffeine content.
  • While pre-workout benefits body-builders and athletes, the average gym-goer can opt for coffee.

Sometimes it can be hard to peel ourselves off the couch and get to the gym, and relying on an outside source like a workout buddy or a feel-good song can be just the pick-me-up. But for some, the extra energy boost comes from pre-workout supplements.

Pre-workout supplements - often shortened to pre-workout - have dominated the world of sports and bodybuilding since the eighties and have recently gained a resurgence in popularity among exercise enthusiasts.

We spoke to three dietitians to help you figure out if you need to be taking pre-workout before a sweat-sesh, how effective they are, and their adverse side effects.

What does pre-workout do?

Pre-workouts are dietary supplements used to boost overall performance during exercise. They're usually sold as powders, but can also be found as capsules and drinks.

Pre-workout is different from other protein powders because the purpose of it is to boost your energy levels before a workout, instead of recovering after a workout, says Rachel Silva RD, a dietitian practicing at The Nutrition Clinic for Digestive Health.


Common pre-workout supplement ingredients

According to Amy Goodson, RD, there are a few common ingredients found in pre-workout supplements intended to improve performance:

  • Caffeine: This is the energy-boosting component of most pre-workout supplements. Caffeine is a common stimulant that affects the nervous system and can help you feel energized, refreshed, and focused.
  • Creatine: Creatine is an amino acid, which may improve muscle building during a workout.
  • Beta-alanine: Beta-alanine is an amino acid. When taken consistently, beta-alanine can help buffer lactic acid buildup in muscles allowing you to exercise harder longer, says Goodson. However, it must typically be consumed for a month to reap the benefits.
  • Arginine: Arginine is an amino acid that helps stimulate vasodilation - the dilation of blood vessels. This delivers more oxygen and nutrients to the working muscle and may help you work out harder and longer.

The ingredients in pre-workouts vary from product to product, making it difficult to say whether all pre-workout supplements can improve athletic performances. However, caffeine, which is found in most pre-workouts, is an established performance-boosting supplement.

Latest research: A 2018 review, found that consuming low doses of caffeine one hour before a workout improved performance in both endurance and high-intensity workouts.

"While caffeine can contribute to a slightly elevated metabolic rate, it is unlikely that this change would translate into any quantifiable fat-burning benefits," says Brittany Wehrle, RD, CSSN, a licensed sports dietitian and founder of Fueled and Well.

Alternatively, pre-workout supplements that contain creatine may cause weight gain due to water retention or muscle building. However, it does not cause you to gain fat.


Should I take a pre-workout supplement?

The average gym-goer doesn't need to take pre-workout supplements. "While some consider them beneficial, for many a cup of coffee and granola bar can provide the same benefits to energy," says Goodson.

However, individuals with specific strength or aesthetic goals may benefit from a pre-workout, says Wehrle. A 2018 review found consistent consumption of pre-workout during a training program increased lean muscle mass. This means pre-workout may be best suited for athletes or high-intensity exercisers looking to take their workouts to the next level.

Is pre-workout bad for you?

While pre-workout supplements can be beneficial for some, they aren't for everyone.

"If you're lacking energy before and during your workouts, turning to a supplement shouldn't be your first choice," says Silva.

Instead, she recommends exercisers eat a healthy diet, get enough sleep, and stay hydrated before reaching for a pre-workout.


"My philosophy is to always change our food choices first, and use supplements when needed and as appropriate to help you reach your goals," Silva says.

According to Wehrle, pre-workout supplements can cause cardiac or digestive issues like nausea or diarrhea. Therefore, certain groups of people should avoid taking pre-workouts, including:

The high caffeine content in pre-workouts is often what causes health issues. On average, pre-workout supplements have 150 mg to 300 mg of caffeine - the equivalent of about one-and-a-half to three cups of coffee. The highest amount of caffeine for adults to consume safely is 400 mg. Beyond that, consuming too much caffeine may cause:

"Excessive caffeine can also affect your body's ability to properly regulate its temperature, which can become dangerous in the hot summer months," says Wehrle.

Important: Supplements, like pre-workout powders, are not regulated by the FDA. That's why you should only buy supplements that are third-party tested. You should be able to tell if a supplement is third-party certified by the label.


"These third-party testing protocols test for label accuracy and the presence of any hidden or contaminated substances, which is really important due to the lack of strict regulation on the supplement industry," Wehrle says. "This ensures you are getting a safe product and getting what you are paying for."

Insider's takeaway

Pre-workout supplements contain quite a bit of caffeine, which likely explains why they can make your workout easier to power through - especially for extreme exercisers.

However, the average gym-goer is better off fueling themselves through whole foods, proper hydration, and quality sleep rather than getting their energy from a powder or pill.

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