What Is Pre-Workout?

Thirsty female athlete drinking water in the gym's locker room

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  • Pre-workouts are dietary supplements that may potentially help you perform better and recover easier after a workout.
  • Although they are generally safe, pre-workouts do come with some risks (e.g., interactions with medications), and there are mixed results related to their effectiveness.
  • If you're considering using these products, it's best to speak with a healthcare provider beforehand.

Whether you've been working out for a while or just beginning your workout journey, it's possible that you've heard of taking a pre-workout supplement.

Pre-workouts are nutritional supplements that you can take before exercising. The use of these supplements has been suggested to help you perform better while engaging in your workout routine.

If you've never used pre-workout before, you might be curious about how they work, and what ingredients they contain. Here's what you need to know about pre-workout.

What Does Pre-workout Do?

There are a few things that these types of supplements claim to do, including:

  • Improving your energy levels
  • Enhancing your performance during exercise
  • Helping with post-workout recovery
  • Prepping your body for workouts
  • Reducing exhaustion or the chance of training injuries

What Is in Pre-workout?

Pre-workouts can come in different forms (e.g., pills, powders, or bars), and they also vary in terms of the ingredients they contain. Ingredients in dietary supplements for exercise or athletic performance range from vitamins and minerals to proteins and plant-based ingredients (e.g., ginseng or beet juice).

For supplements geared toward exercise and athletic performance, there are 21 different types of ingredients that may be used. Some of them are naturally occurring, either in your body or in plant- or animal-based foods. However, not all of them work for enhancing your performance during workouts.

Some of the ingredients that normally might be used in a pre-workout supplement are:

  • Caffeine: Caffeine is a stimulant that may help cognition and performance during exercise by reducing fatigue
  • Branched-chain amino acids (BCAAs): Thought to improve muscular endurance and reduce muscle damage caused by exercise
  • Nitrates (nitric oxide agents): Increase the flow of blood to muscles that you are actively using
  • Creatine: Improves performance and helps with challenging adaptations in training
  • Beta-alanine: Enhances exercise at the high-intensity level by reducing build-up of lactic acid that can cause fatigue in athletes

It's important to know what ingredients are in your pre-workout of choice. You'll want to check the label to ensure that all ingredients are listed with the amounts of each ingredient clearly indicated.

Additionally, dietary supplements should only include "dietary ingredients" (e.g., vitamins, herbs). No pharmaceutical ingredients (e.g., prescription medications) are permitted in supplements. Companies that make supplements are also not allowed to say that the supplements can be beneficial in diagnosing, treating, curing, or preventing diseases.

How Long Does It Take to Kick In?

If you plan on taking any pre-workouts, you can do so shortly before you begin your workout.

One study found that participants who took pre-workout supplements did so between 15 to 60 minutes prior to exercise. However, most took the supplements between 15 to 30 minutes, which is the time interval matched with what most supplement manufacturers have recommended on their product labels.

More research is needed to determine exactly when pre-workout kicks in and how long you might feel their potential benefits. However, the length of time it takes for pre-workout to work and how long the effects last may, in part, depend on the type of supplement you have taken.

For example, if you take creatine as a supplement on its own, it can be beneficial in the short term (i.e., for minutes) when you do an exercise such as a sprint. At the same time, creatine has not been shown to be helpful for longer periods of time.

Is Pre-workout Safe?

Some studies have indicated that, for short-term use (i.e., eight weeks or less), pre-workouts are safe to take. More research is needed to find out if using them for longer is more, less, or just as safe.

Pre-workout supplements are not recommended for everyone. Supplements used to help performance are for adults only in the majority of situations.

Also, individuals with medical conditions such as cancer, heart problems, Parkinson's disease, and thyroid disorders (e.g., hypothyroidism) should also consult a healthcare provider before using supplements. Some supplements can interact with medicines or treatments and make them less effective.

Always Talk to Your Healthcare Provider

Pre-workouts contain extremely high doses of caffeine that can be harmful and even life-threatening, especially to young athletes and kids. Always talk to your healthcare provider before adding a pre-workout to your workout regimen.

Side Effects

Pre-workout supplements can have side effects like nutritional supplements in general. The potential for side effects can be different among ingredients and dosages of those ingredients. Some side effects that might occur include:

  • Diarrhea
  • Nausea
  • Abdominal cramps
  • Heartburn
  • Fatigue
  • Insomnia
  • Headaches
  • Dizziness
  • Weight gain (from water retention)

Medication Interactions

There are also ingredients in pre-workout supplements that may interact with any medications you are taking. Ginseng is an ingredient that can make blood-thinning medicines less effective. Also, medications for ulcers can make it so caffeine takes longer to leave your system — resulting in the potential to experience caffeine side effects for longer.

Inappropriate or Prohibited Ingredients

Other than checking the label for the amounts of ingredients, you should also consider other pre-workout options if there are any ingredients that shouldn't be in the product you want to use.

Although the U.S. Food and Drug Administration (FDA) does not review or approve exercise and athletic dietary supplements, the agency does regulate them. Beyond prescription medications, other ingredients that can be inappropriate for use in dietary supplements include:

  • Stimulants
  • Steroids
  • Hormone-like ingredients
  • Other controlled substances such as opioids, depressants, hallucinogens, etc.
  • Unapproved drugs

Some ingredients are no longer allowed to be in dietary supplements because the FDA has deemed them unsafe and because they have no research support for their effectiveness. The ingredients include:

  • Androstenedione: A prohormone that the body turns into testosterone
  • Dimethylamylamine (DMAA): A stimulant
  • Ephedra: A plant that contains stimulant compounds called ephedrine alkaloids

All three ingredients were banned from inclusion in supplements, with androstenedione and ephedra becoming prohibited in 2004 and DMAA becoming prohibited in 2013.

Is Pre-workout Effective?

The effectiveness of pre-workout supplements can vary. Individual ingredients in the supplements can have their own levels of effectiveness, but those levels may change when individual ingredients are combined.

For example, the use of caffeine has been mixed in studies when it comes to efficacy. One study found that, compared to individuals who used placebo and baseline treatments, participants who used a caffeine-based supplement had an increased average amount of power.

However, other research found that using a pre-workout supplement, or taking a similar dosage of caffeine, did not improve performance during resistance exercise.

There's also the idea that different supplements may be more or less effective for some types of workouts than others. Research has suggested that multi-ingredient pre-workout supplements (MIPS) are great for muscular endurance but not strength. MIPS also offered mixed results for power and possible positive results for endurance exercises.

Other Considerations About Pre-workout Supplements

Though some pre-workout supplements can be helpful for performance, it's important to ensure that they are not substitutes for nutrients you get from your diet like:

If you're exercising for long periods of time (e.g., more than an hour) or in environments where you'll lose a lot of fluids, staying hydrated is another way to perform at your best. Additionally, having proper physical conditioning and training can boost performance as well.

But if you're still interested in taking pre-workout, consult a healthcare provider to determine if and what type of pre-workouts might be appropriate for you.

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  4. Office of Dietary Supplements. Dietary supplements for exercise and athletic performance - fact sheet for healthcare professionals.

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