The workout supplements space is filled with options, from protein and pre-workout powders to ashwagandha and turmeric. With all of these products available on the market, it can be difficult to know which ones are really worth it.
To cut through the noise, we asked fitness and nutrition experts: If someone wants to add just one supplement to support their workouts, what’s the best choice? Here’s what they said.
Experts agreed on the best workout supplement: creatine.
Creatine is a naturally occurring compound in the body that primarily supports muscles. Your body makes about half of the creatine you need, and the rest must come from food or supplements.
“Decades of research show it safely and effectively boosts strength, muscle recovery, and high-intensity performance,” Lena Beal, MS, RDN, LD, CCTD, cardiovascular dietitian at Piedmont Atlanta Hospital and spokesperson for the Academy of Nutrition and Dietetics, told Health. “Unlike trendy products that come and go, creatine has a robust evidence base in athletes and everyday exercisers alike.”
Creatine works by helping regenerate adenosine triphosphate (ATP)—a molecule that serves as your muscles’ primary energy source—so you can train harder, lift heavier, or run longer before fatigue sets in, Beal explained.
Research has also linked regular creatine supplementation to other benefits, such as lowering cholesterol, managing blood sugar, and enhancing cognitive function.
“Compared to other supplements, creatine stands out,” Tony Ambler-Wright, product manager and master instructor at the National Academy of Sports Medicine (NASM), told Health.
He cited creatine’s proven ability to “increase strength and muscle mass, support greater improvements during resistance training, enhance cognitive performance in the sleep-deprived, and possibly improve memory, particularly in older adults.”
While creatine was the undisputed winner, Melinda Ring, MD, executive director of the Osher Center for Integrative Health at Northwestern University, also recommended beetroot.
The natural nitrates in beetroot convert to nitric oxide in the body, which widens blood vessels, increases blood flow, and improves the delivery of oxygen to working muscles, she explained.
“This leads to improved exercise efficiency—essentially allowing you to do more work with less energy expenditure,” Ring told Health. “Recent studies show beetroot can improve time to exhaustion by 18–25% and increase power output by 6–7%.”
To boost workout performance, Ring recommends taking about 5 grams (g) of beetroot powder or drinking a 1/2 cup of beetroot juice two to three hours before exercising.
Kat Barefield, MS, RDN, a registered dietitian and member of the NASM Strategic Advisory Board, also recommended creatine—but only after meeting your protein needs, which should be about 0.7 g of protein per pound of body weight.
“For all exercisers, regardless of the goal, protein should be optimized first before adding supplements to boost workouts,” she told Health. “This can be achieved by consuming more protein or adding a protein supplement, such as whey protein or a plant-based alternative.”
When purchasing creatine, look for creatine monohydrate, specifically, which is the best-studied version of the supplement, Shane Davis, MD, a non-operative sports medicine physician at Tufts Medical Center, told Health.
He also advises choosing products that have been third-party tested, especially those with USP or NSF certification.
For dosing, experts said to take 3 to 5 milligrams (mg) per day.
Lee A. Mancini, MD, a sports and family medicine doctor with UMass Memorial Health and a member of the American Medical Society for Sports Medicine, told Health that some people do a “loading phase” of taking 20 mg every day for a week, but research shows it’s not necessary.
Ambler-Wright agreed: “It’s becoming more common to skip the loading phase unless fast results and saturation are needed, because the daily low dose is usually easier to tolerate, particularly for those who experience gastrointestinal upset with higher-dose creatine supplementation.”
Experts said the safety of creatine has been demonstrated in many studies. The National Institutes of Health lists several potential side effects of creatine, including water retention, nausea, diarrhea, muscle cramps, muscle stiffness, and heat intolerance. But experts said these are rare at the recommended dose.
“An analysis of adverse event reports across North America, Europe, and Australia over 50 years found creatine referenced in only 0.0007% of reports despite billions of usages,” Ambler-Wright said. “Multi-year clinical studies demonstrate no significant adverse events in populations ranging from infants to the elderly.”
The only group creatine may not be right for is those with a kidney dysfunction, who should consult a healthcare provider before starting the supplement, experts said.
Mancini also recommended making sure you’re drinking enough water while on creatine, as proper hydration can help with water retention—the most common side effect.
If you’re looking to take just one supplement to support your workouts, experts recommend creatine. The highly studied supplement supports exercise performance, muscle growth, and workout recovery, while offering additional benefits for your heart and brain.
“Creatine monohydrate is a standout supplement for athletes, older adults, and anyone serious about fitness,” Ambler-Wright said, “because of its unmatched combination of safety, efficacy, and cost-effectiveness.”
