What Is Pre-workout—And Is It Worth Trying?
Experts explain the potential benefits and risks of taking these supplements.
If you're someone who's looking to maximise your workout, you may have tried—or are curious about trying—the supplement, pre-workout. But what is it, and what does it do?
There is no formal definition of pre-workout, says Dana Angelo White, MS, RD, ATC, of Dana White Nutrition. "Pre-workout has become a trendy term used to describe dietary supplements marketed to promote performance during exercise", she says, adding that a few other claims associated with pre-workout products include increased energy levels, improved circulation and better focus.
Typically sold in powder form and designed to be mixed with water (but can also be found as canned beverages, shakes, capsules and bars), pre-workout supplements are likely to contain a blend of potential stamina-boosting substances including amino acids, creatine (an amino acid found naturally in muscle cells), beta alanine (a non-essential amino acid produced in the liver that naturally occurs in meat), caffeine and nitric oxide precursors, says Sharon Gam, PhD, CSCS, ACE-HC.
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"Even though you could buy each of those ingredients separately, pre-workout supplements claim that the combination of ingredients provides better effects than each would on its own", she says.
While these products are generally targeted for tough endurance-related workouts, those who exercise at a more moderate intensity may feel like they need an extra dose of energy to gear up for their workout, too, says Gam.
Along with giving the body a boost before sweating it out, other touted benefits include increased muscle power and reaction time, as well as a quicker recovery period. As is the case with all supplements, though, make sure you consult with your doctor before taking pre-workout—especially since some ingredients may interact with prescription and over-the-counter medications.
What Does Pre-workout Do?
In a nutshell, the science around the dietary supplement is quite limited.
"While there is research to show that pre-workout supplements can improve exercise performance, the evidence isn't very strong, and the findings are mixed", says Gam.
In a small-scale study, 12 male power athletes in their early 20s were instructed to consume either a high-energy drink or a placebo drink before participating in four, two-minute performance tests that gauged quickness and reaction. According to the results published in a 2009 issue of the Journal of the International Society of Sports Nutrition, the volunteers who drank the energy beverage—which contained caffeine, vitamin C and herbal and botanical compounds—significantly demonstrated faster reaction time and enhanced self-perceived feelings of energy and focus compared to the placebo group.
Another small study examined the possible effects of a multi-ingredient performance supplement containing creatine and beta-alanine on muscle mass, lean body mass and lower-body strength. The authors found that the participants (24 men in their 20s who weight train) who took the pre-workout supplement and trained three days a week for eight weeks "increased their strength about nine percent more than another group who did the same training programme without the supplement", explains Gam.
Also, research conducted by exercise scientists from the University of South Florida that featured 13 males (between the ages of 20 and early 30s) found that taking a caffeine-based pre-workout over a four-week period resulted in significant improvements in anaerobic peak (performing at maximum speed) and mean power values (average power exerted). However, White is highly sceptical of these findings.
"The main ingredient in most pre-workout supplements is a stimulant or combination of various stimulants", she explains. "Stimulants give the illusion of energy—a neurological jolt, but not true energy. The truth is, only calories can provide energy".
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Furthermore, Gam cautions that funding could have contributed bias to the results. "It's important to note that many of the studies were done by scientists with financial ties to supplement companies, so you may want to take these benefits with a grain of salt", she adds.
Potential Risks of Pre-workout Supplements
Pre-workout is generally considered to be safe, but both White and Gam address one potential issue with the supplement: overconsuming caffeine or other stimulants.
"Stimulant toxicity is a potential risk", warns White. "Since dietary supplements are poorly regulated, anyone that takes them may be putting themselves at risk for ingesting improper dosages and adulterated products, as well as harmful side effects".
In fact, a 2019 study published in the journal Nutrients revealed that more than half (54 percent) of the 872 participants (between the ages of 18–65) self-reported heart abnormalities, skin reactions and nausea after taking pre-workout supplements. White adds that ingredient transparency is another serious issue.
"In other words, inaccurate labels, 'proprietary blends' with undisclosed ingredients and lack of consistency across products", she says, in reference to research that uncovered nearly half of 100 products concealed the dosages of various ingredients.
In fact, the authors of the study in Nutrients point to pre-workout supplements made with proprietary blends as the potential cause for a majority of the adverse side effects experienced by participants, since those ingredients aren't listed on the label. "It is difficult to discern the primary cause of these side effects, as the majority of MIPS (multi-ingredient pre-workout supplement) contain proprietary blends of ingredients with varying amounts of ingredients and some ingredient amounts not disclosed", the authors wrote.
"It's also possible that pre-workout supplements could be contaminated or contain dangerous substances that aren't listed on the label", says Gam. "For example, a pre-workout [supplement] was found to contain a methamphetamine-like (a highly addictive stimulant) substance and subsequently recalled".
Those with high blood pressure may want to avoid pre-workout altogether. One small-scale 2018 study in the Journal of the International Society of Sports Nutrition examined any possible cardiovascular side effects linked to pre-workout supplements. Among the 15 healthy, active females in the trial, a single dose was shown to raise diastolic blood pressure (the bottom number, which measures the pressure in the arteries between heartbeats).
The Bottom Line
Before you take a pre-workout supplement, check in with your doctor. If you get a thumbs-up from your doctor, Gam advises purchasing a product that has been tested by a third party, such as the NSF International, USP (United States Pharmacopeia) or ConsumerLab.
"I would also suggest avoiding products with artificial sweeteners and other additives", she says. White, on the other hand, strongly encourages others to skip the pre-workout fad entirely.
"Honestly, I don't think pre-workout supplements are beneficial in any way—I've seen many people use these products and regret it", she says. "My best recommendation would be a measured, appropriate dose of coffee or tea along with food in order to get in some calories and a safe amount of caffeine".
And why rush your progress? While pre-workout can offer what appears to be a quick fix, allowing your body the time it needs to build strength and endurance as you move through your training cycle is key. Remember, the main priority should be getting adequate rest and nutrition, as they both play a huge role in recovery and can set you up for success for your next workout.
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Words by Amy Capetta