Do Pre-Workout Supplements Actually Work?

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Pre-workout supplements designed to improve your athletic performance and provide an extra boost during exercise have become popular among gym-goers, athletes, bodybuilders, and trainers. As sales of sports nutrition supplements continue to skyrocket, many fitness experts have begun to wonder whether these pre-workout products actually work. Or are they all just hype?

The Supplements Industry

Manufacturers of pre-workout supplements, like those that produce vitamins, diet pills, and other nutriceuticals, are largely unregulated by the U.S. Food and Drug Administration (FDA). As such, they are not burdened by the rigorous research standards required of pharmaceutical drug manufacturers.

Even the simple aspirin you take has undergone (and continues to undergo) rigorous testing to evaluate how safe and effective it is within different populations and under different medical circumstances. None of this is required of supplements, which are not classified as drugs, but are rather placed under a special food category.

While the FDA provides labeling and advertising guidance (mostly telling manufacturers what not to say), only the most outrageous claims tend to be challenged by the regulators. By and large, the suggestion of benefits—including how well a supplement will improve your health, mood, or performance—is rarely challenged, even if there is little evidence to support the claims.

This is not to say that the dietary supplements on the market are less than beneficial; many are. But it's important to take time to research a product and not accept a manufacturer's word at face value.

Pre-Workout Supplement Ingredients

Pre-workout supplements usually contain a proprietary blend of ingredients. While manufacturers insist that their unique blend is responsible for the energy boost, there is invariably just one ingredient producing the buzz: caffeine.

Not surprisingly, pre-workout supplements are loaded with it. In fact, some top-selling brands contain around 400 milligrams (mg) per dose. That's equal to drinking four cups of coffee. Many leading brands range anywhere from 150 mg to 300 mg per dose.

Pre-workout supplements contain other ingredients that athletes and bodybuilders regularly turn to, including creatine, L-arginine, β-alanine, taurine, and betaine. Others include guarana, a plant-based stimulant which contains twice the amount of caffeine per gram as coffee beans. While there is empirical evidence supporting the use of some of the ingredients, others are supported only by anecdotal proof.

Caffeine 

Irrespective of exercise, caffeine is known to increase metabolic rate, improve endurance, and reduce fatigue. It also stimulates the central nervous system, enhancing brain function for a more productive and effective workout.

For best results, caffeine should be consumed in low to moderate doses (around 3 grams per kilogram of body weight). For a person weighing 150 pounds (68 kilograms), that translates to roughly 200 mg, or two cups of coffee.

Creatine

Creatine is one of the most popular bodybuilding supplements, and is backed by an increasing body of evidence. Creatine is synthesized from amino acids and concentrated in muscle tissues to enable quick bursts of energy, like sprinting or powerlifting.

According to a review of studies published in the "Journal of the International Society of Sports Nutrition," creatine supplementation is effective in promoting muscle growth, strength, and performance during high-intensity interval training (HIIT).

The recommended creatine dose is 5 grams taken incrementally over a 5- to 7-day cycle, with a pause of 7 to 14 days before the cycle starts again. Most experts recommend taking creatine on its own, instead of as part of a multi-ingredient supplement, to better control your intake.

L-Arginine

L-arginine is one of the branch-chained amino acids necessary for protein synthesis. L-arginine is also central to creating nitric oxide, a compound that relaxes your blood vessels for better blood flow and oxygen exchange. Despite these metabolic functions, there is little scientific evidence to support claims that supplementation can improve athletic performance.

β-alanine

β-alanine, also known as beta-alanine, is a naturally occurring amino acid produced in your liver that promotes nerve signal function. Some studies have suggested that supplementation may delay the onset of neuromuscular fatigue and enhance athletic performance.

On the downside, the supplement can sometimes overstimulate nerve cells, causing tingling sensations known as paresthesia. Because the incidence of this side effect can vary by dose, it is often better to take an individual supplement to better control intake.

Taurine

Taurine is one of the most abundant amino acids found in the brain, muscles, and organ tissues. It functions as a neurotransmitter, stabilizing cell membranes and regulating the transport of nutrients throughout the body.

While taurine is vital to maintaining metabolic function, there is conflicting evidence as to the role supplementation plays in improving athletic performance. According to research published in the "Journal of Strength and Conditioning," the combined use of taurine and caffeine may actually accelerate, rather than delay, muscle fatigue.

Betaine

Betaine is an amino acid that helps process fat and maintain normal liver function. A small study conducted in 2013 suggested that betaine supplementation improved body composition, muscle size, and work capacity in 23 people who underwent a six-week course of bench press and back squat training. While improving power, betaine supplementation did not appear to increase strength.

Effectiveness of Pre-Workout Supplements

Pre-workout supplements heighten your exercise performance simply by exposing you to high levels of caffeine. There is no evidence that the combined use of the ingredients will increase performance in ways that improve your physical or health outcomes.

In addition, research shows that the products not only lack scientific evidence but may pose health risks. These risks are higher for people with high blood pressure, heart rhythm problems, diabetes, or pre-diabetes.

In terms of exercise performance, research suggests that pre-workout supplements can increase blood flow in the muscles but only during high-intensity workouts (greater than 80% exercise load). But there was no evidence of improved body composition or strength compared to a matched set of individuals who didn't take the supplements.

A Word From Verywell

While it may seem handy to combine all of your workout supplements in one scoop, you can usually spend less and get more control by purchasing supplements individually. As for caffeine, enjoy it in moderation. While it may help you bulldoze through a workout, it can also promote fluid loss and lead to dehydration. With any supplement you take, it is best to talk to your doctor to ensure that the benefits outweigh the risks.

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