Do Pre-Workout Supplements Actually Work?

Feeling a Boost Doesn’t Mean a Stronger Body

Man with sport nutrition
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Pre-workout supplements—ones designed to improve your athletic performance and provide an extra "boost" during exercise—have become the rage among not only gymgoers but many athletes, bodybuilders, and trainers. As sales of sports nutrition supplements continue to skyrocket, racking up sales in excess of $20 billion annually, many fitness experts have begun to wonder whether these pre-workout products actually work or are all just hype?

About 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 per se 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 meant to suggest that many of the supplements on the market are anything less than beneficial; many are. Rather, it suggests that you take time to research a product and not take a manufacturer's word at face value.

Breaking Down the Ingredients

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

Not surprisingly, pre-workout supplements are loaded with it. In fact, one of the top-selling brands, GNC Pro Amp, contains loss less than 400 milligrams (mg) per three-pill dose. That's equal to drinking four cups of coffee prior to a workout. Most other 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 compared to coffee beans.

While there is evidence supporting the use of some of the ingredients, others are supported by anecdotal, rather than empirical, proof.

Caffeine 

Irrespective of exercise, caffeine is known to increase an individual's 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 doses 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 one 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 as an individual supplement to better control your intake.

L-Arginine

L-arginine is part of the branch-chained amino acids necessary for protein synthesis. L-arginine is also central to creating nitric oxide, a compound which 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 or a multi-supplement in tablet form 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 maintains 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

Putting it simply, 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.

A study published in the American Journal of Health-System Pharmacy supports this assertion, concluding that the products not only lack scientific evidence but may pose health risks to people with high blood pressure, heart rhythm problems, diabetes, or pre-diabetes.

In terms of exercise performance, research published in the International Society of Sports Nutrition suggested that pre-workout supplements can increase blood flow in the muscles but only during high-intensity workouts (greater than 80 percent exercise load). With that being said, 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

In the end, all of the marketing buzz surrounding pre-workout supplements can be attributed to caffeine. While it may seem handy to combine all of your workout supplements in one scoop, you can usually spend less and get more by purchasing the supplements individually.

As for caffeine, enjoy it with moderation. While overuse may help you bulldoze your way through a workout, it can also promote fluid loss and lead to dehydration. As with any supplement you take, it is best to run the ingredients by your doctor to ensure that the benefits outweigh the risks.

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