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Being Picky About Performance Supplements by Christina Badaracco, MPH, RDN, LDN

Demand for supplements that improve performance and recovery around physical activity continues to increase around the world. The US market is estimated to reach nearly $9 billion in 2024, and it’s expected to continue to grow based on the increase in the overall supplement market (especially during the COVID-19 pandemic) and interest in health and fitness in general. How do consumers know what they should buy to optimize performance for the sake of good health—and what is even worth the money? 

What are the most common performance supplements, and how can they benefit consumers? 

An enormous variety of supplements are available on the market, and a subset is focused on athletic performance. Performance supplements may claim to improve strength or endurance, help achieve a performance goal more quickly, increase tolerance for intense training, prepare the body for exercise, reduce the likelihood of injury during activity, assist with recovery or yield other positive effects. Powders are the most popular format thanks to their ease of use, but supplements can also be gummies, gels, tablets, capsules, liquids, shakes or bars. The following sections review the most common types and their purported benefits. 


Beets provide a concentrated source of nitrates, which our bodies convert into nitric oxide. (Note this plant-based source of nitrates is beneficial, unlike the nitrates used as preservatives in some processed meats that convert into carcinogenic nitrosamines.) Nitric oxide increases blood flow to muscles by dilating blood vessels, providing more oxygen and other nutrients. Therefore, beetroot juice, juice concentrate, and powders are sometimes consumed to improve aerobic performance and endurance. While a recommended dosage is yet to be established, most studies have used up to 500 mL (or 2 cups) daily — providing roughly 300–700 mg of nitrate — per day. There are no significant safety concerns or risks of adverse effects. Some evidence suggests that beetroot can enhance performance for endurance athletes, but few trials have been conducted and the overall evidence base is mixed.  

Branched-chain amino acids

Amino acids are the building blocks of protein molecules. Among the 20 total amino acids used in human biology, a subset is known as branched-chain amino acids (BCAAs); they include valine, leucine and isoleucine. They are found in animal- and plant-based proteins and various supplements (e.g., shakes, bars and capsules). The body’s use of BCAAs increases during intense exercise, causing their concentration in the body to decrease. Consuming them through the diet shortly before or after exercise can help preserve and augment lean body mass by stimulating protein synthesis (or formation). The proposed safe upper limit for supplementation is 0.24 grams per pound of body weight. Overall, the evidence for the effectiveness of BCAA supplements in boosting muscle synthesis is inconsistent. 


Comprised of three amino acids, creatine is produced by all vertebrates and is found in muscles and the brain. It facilitates the recycling of a molecule known as adenosine triphosphate (ATP), the body’s basic form of energy. Creatine can be taken as a supplement shortly before or after exercise to improve strength and gain muscle, particularly to produce more energy for high-intensity exercises (e.g., jumping, lifting heavy weights). Creatine monohydrate is widely thought to be the preferred form. Consuming creatine supplements together with a carbohydrate may increase its effectiveness. While decades of research have shown that it can be effective for this purpose and is generally well-tolerated, it can lead to side effects such as upset stomach, high blood pressure and kidney damage. Also, its benefits are currently being researched for various therapeutic areas, such as osteoarthritis and Parkinson’s disease.


This amino acid is fundamental for the body to synthesize protein, and its concentration in the body is reduced with prolonged, exhaustive exercise. Animal products (including dairy and eggs) contribute the most glutamine to the diet, but it can also be found in legumes, some vegetables and fermented foods. Glutamine is conditionally essential, meaning that our bodies can normally synthesize enough to meet our needs, but certain conditions (such as trauma or major surgery) can limit its formation. When available glutamine is insufficient for proper functioning, we must meet our needs by consuming it from external sources. It may be consumed as a supplement to increase muscle protein synthesis. Supplement forms include powders, bars and capsules. While glutamine is typically tolerated at doses up to 0.3 grams per pound of body weight, evidence for its effectiveness in healthy adults is inconsistent. 


Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite (or downstream product) of leucine that helps maintain muscle proteins and increase muscle mass following exercise. (It can also be helpful for augmenting muscle mass due to age-related muscle loss, known as sarcopenia, and diseases associated with weight loss.) HMB can reduce post-exercise muscle damage, speed recovery, improve strength and increase muscle mass following resistance training. It is found in very few foods, so supplementation (such as in powders, bars and capsules) is the primary way to consume it. Most healthy people can produce as much as their bodies need, though. Overall, studies of HMB to increase muscle mass or to prevent or reverse muscle wasting are limited and results are mixed. It is likely most useful for people recovering from an injury.


Because muscles are comprised of protein, proteins must be made continuously for the ongoing growth, repair and maintenance of muscle tissue. Thus, athletes often seek to supplement their diet with isolated forms of protein, which will be digested and formed into new molecules (including new proteins). (Learn more about protein supplementation in this post.) Ingesting protein shortly after exercise may be especially important; indeed, the 2016 Nutrition and Athletic Performance Joint Position Statement by three top professional associations recommended consuming roughly 10 grams of essential amino acids (which is between 15 and 25 grams of protein) up to two hours after exercise, followed by 0.14 grams per pound of body weight every few hours to optimize recovery. This specification was removed from their updated 2020 Joint Position Statement, which instead emphasized the importance of an elevated 0.54–0.77 grams per pound of body weight for athletes over the course of the day. It noted that these amounts can generally be met through diet alone as long as energy intake is sufficient to maintain weight.

Protein supplements can be made from plants (e.g., peas, soy) or animals (e.g., whey, collagen). Due to its chemical structure, whey protein is digested more quickly — stimulating protein synthesis more quickly — than other proteins. They can be purchased in bars, beverages or powders to make into shakes. Protein supplements have also been extensively studied for their benefits in treating catabolic diseases (such as cancer) and associated malnutrition and wasting. 

What are the potential risks of taking performance supplements? 

In the US, dietary supplements — including those used for performance — are regulated like food rather than medications. That means the US Food and Drug Administration (FDA) does not review them for safety or effectiveness before they are sold to consumers. As such, supplements are presumed to be safe unless found otherwise.

A 2018 nonprofit Clean Label Project study measured the levels of more than 150 heavy metals, bisphenol A (or BPA), pesticides and other contaminants in 134 protein powders and drinks. They found that almost all products contained detectable levels of at least one heavy metal, and more than half contained BPA. (Notably, plant-based proteins contained more of them — likely because plants are especially prone to absorbing heavy metals from the soil. Also, organic supplements contained more heavy metals but less BPA.) Refer to this previous Insight for more information about the problems associated with consuming heavy metals. 

Therefore, keep in mind the following potential caveats when considering performance supplements:

  • They may be contaminated with heavy metals and other undisclosed ingredients. 

  • They may not actually contain the ingredients (or the ingredients’ amounts) claimed on the package — or be as effective as their claims suggest — so they could be a waste of money.

  • They could interact with other medications or supplements you are taking.

  • They almost always come in plastic bottles, so the packaging further adds to our plastic pollution crisis.


How do I know which performance supplements I should take? 

  • Talk with your primary care physician and/or dietitian about your goals related to physical fitness to determine which supplement(s) — and how much — you could consider taking. Be sure to disclose all other supplements and medications you are taking to avoid any negative interactions.

  • Read more information about these supplements and consider which brands to buy or avoid based on ConsumerLab’s analyses of their contents. Refer to the Clean Label Project’s website specifically for protein supplements. Also, you can look for an independent, accredited certification mark on the bottle, like NSF Certified for Sport® or USP, to ensure a supplement is accurately labeled and not contaminated.

  • For more evidence-based information about the contents and effectiveness of the supplements described above (as well as others), visit the NIH Office of Dietary Supplements website.

  • Check the adverse event and product complaint reports in the FDA’s CFSAN Adverse Event Reporting System (CAERS), as well as recalls and safety alerts, before purchasing a new supplement—especially if a credentialed health professional has not recommended it.

  • Remember that you can’t make up for a deficient eating pattern with extra training or supplements. Dietary supplements should complement a well-balanced diet during training, not replace or take priority.


A list of resources can be found here.

Christina Badaracco, MPH, RDN, LDN

Christina Badaracco, MPH, RDN, LDN, works as a healthcare consultant, educator and thought leader, focusing on evidence generation and advancing the role of nutrition in healthcare. She also regularly writes, teaches and develops curriculum about nutrition, culinary medicine and sustainable agriculture — including publishing The Farm Bill: A Citizen's Guide in 2019 and five cookbooks with the Transamerica Institute and co-developing a culinary medicine elective at the Georgetown University School of Medicine. Christina previously worked for Avalere Health, the EPA, Teaching Kitchen Collaborative, Oakland Unified School District, NIH Clinical Center and more. She is the incoming president of the DC Metro Academy of Nutrition and Dietetics, is on the board for Slow Food DC, supports the Teaching Kitchen Collaborative's nutrition working group and contributes to various other organizations. She earned her Master of Public Health from the University of California, Berkeley and her bachelor's degree in Ecology and Evolutionary Biology, with a minor in Italian Language and Culture, from Princeton University. She completed her dietetic internship at Massachusetts General Hospital.

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