Competition is often at the heart of athletic endeavors. Whether competing with oneself, a team or a rival, athletes frequently look for an extra edge to enhance performance and secure the win. It is thus unsurprising that many athletes are drawn to the promises of supplement companies who specifically market to these inner desires. The truth behind nutritional supplements, however, may not always align with these claims.

Buyer Beware

Contrary to popular belief, just because a supplement is approved for the market does not mean it is safe or effective. Due to The Dietary Supplement Health and Education Act of 1994, “the Food & Drug Administration (FDA) can only ban a supplement if the FDA finds proof that the supplement is dangerous.” This ban typically occurs after the public is harmed, as companies are allowed to sell products that are potentially unsafe or ineffective until reports confirm the supplement causes bodily harm or death. A recent example would include the one death and 29 instances of liver failure, and acute hepatitis due to the supplement OxyELITE PRO, which had received previous warnings to remove the banned substance 1,3 Dimethylamylamine HCL (DMAA).

Evidence of Potential Harm

Investigations from the National Network of Liver Specialists, for instance, indicate that upwards of 20% of drug-related liver injuries are due to dietary supplements, and that “70 percent of dietary supplement companies are not following basic quality control standards that would help prevent adulteration of their products.” Other analyses, such as those reported by Consumer Reports in 2010, found countless instances of “supplements contaminated with heavy metals, pesticides or prescription drugs being sold to unsuspecting consumers.” The inclusion of unlisted additives in supplements have not only harmed a large number of consumers but have also resulted in a variety of athletes unknowingly failing drug tests and losing eligibility to compete. Despite these offenses, the FDA has failed to reform the current legislation. The FDA itself freely admits that many supplement ingredients and effects remain unknown as only 0.3% have been studied closely enough to determine their common side effects.

Many Supplements Fail to Produce Results

Beyond potential health risks, many products often exhibit little to no benefits to health or physical performance. In an effort to cut costs and boost profits, many supplements are marketed as “proprietary blends.” This allows companies to avoid listing specific amounts of ingredients as a strategy to underdose their product with specific nutrients, and replace actual ingredients with useless, cheap “fillers.” The consumer has no way of knowing what or how much of specific nutrients are in the product they are buying.

Some companies ensure product ingredient integrity by obtaining certifications from U.S. Pharmacopeia (USP), NSF International and These labs will certify that the product contains the amount of the ingredient advertised on the label and that it isn’t contaminated with dangerous substances, such as arsenic, bacteria or lead. These certifications, however, do not provide evidence of or validate health or performance enhancement claims that supplement producers may put forth in their marketing materials or on their product labels. It is important for consumers to know that many supplements are brought to market without appropriate scientific evidence to support the marketing claims that often over-exaggerate benefits to consumers in order to turn a profit.

Supplement companies often employ deceptive marketing

As seen in the Bigger, Stronger, Faster*, scientific studies are rarely available; instead, the marketplace is flooded with paid endorsements from elite athletes. The documentary detailed how many who are paid significant fees to endorse supplements have never touched the supplement in their lifetime and will freely admit, in private, that their personal results in sports performance are related to other factors, like their strength and conditioning regimens for example. Other companies will actually hire scientists to conduct studies on their supplement and control the release of the findings, only allowing those studies that demonstrate positive results to be published. Most consumers, however, cannot identify conflicts of interest or flaws within research that might undercut strong market-driven claims. A primary example of this is the $274 million worth of branched chained amino acid supplements sold in 2015 alongside countless athlete endorsements, despite overwhelming scientific evidence suggesting their inferiority compared to cheaper whey protein or whole food protein sources.

Supplement response is Dose-Dependent

The situation remains complex, however. Even when nutritional supplement use is evidence-based, well-regulated and appropriately dosed, a variety of problems can occur when used without the guidance of a trained health professional. Athletes and non-athletes alike often assume that more of a “good thing,” is always better. This nevertheless remains patently false since numerous substances contain a threshold for effectiveness and some contain a threshold for toxicity. For example, incorrectly dosing an iron supplement can result in vomiting, diarrhea, abdominal pain, irritability and drowsiness. Consuming excess fat soluble vitamins, such as A, E, and K, can result in toxicity over time since fat soluble vitamins are stored in your body’s fat tissue. Failure to cross-reference supplements and medications can also result in unintended consequences because drug-nutrient interactions can lessen the effectiveness of medications or result in extremely unpleasant side effects.

How to protect yourself and your athletic career

Despite the warnings listed above, there are a variety of instances where educated, informed and appropriate use of supplements can enhance health and performance. Similar to how athletes carefully research sporting equipment before purchase and use in training and competition, athletes are strongly encouraged to consult with a professional to understand how to make informed decisions when considering adding supplements to their routine. Adequate intake of Vitamin D, Calcium and Iron, for instance, can sometimes be difficult to obtain from food sources alone. This is especially important for athletes who follow a plant-based eating pattern, those dealing with food allergies or intolerances or athletes who impose dietary restrictions based on religious practices. A Registered Dietitian is uniquely qualified to help an athlete understand if supplements are appropriate for the individual’s situation. A dietitian will first evaluate the balance and adequacy of food choices and will make recommendations to address the quality of the overall diet. Lastly, if supplements are indicated, the dietitian can recommend formulations, brands and doses that are in line with research and safety guidelines.

An Important Reminder

Most sports dietitians agree that food is the foundation of success in sport. Supplements are –“supplemental.” They are meant to be used “in addition” to an adequate and sensible fueling strategy, not to compensate for a pattern of unhealthy eating. As such, supplements are lower on the list of priorities and are not the first line of defense.

Supplements will not replace the fundamentals of good nutrition for an athlete, nor will they make up for longstanding patterns of chronic under fueling, overtraining or inattention to rest and recovery nutrition. To learn more about whether supplements are right for you, consult a Registered Dietitian like the expert on our team!


Matt is a licensed registered dietitian nutritionist and certified strength and conditioning specialist. He is a nutritionist and exercise science advisor for the Walden GOALS program. Matt devoted the early part of his career to refining the art of training elite collegiate and professional athletes. In graduate school, he developed expertise in nutrition, behavior change and eating disorders. Matt now devotes his practice to translating nutrition and exercise science into practical solutions. As a lead member of the GOALS team, Matt is known for his dedication to educating and empowering athletes of all backgrounds to facilitate a full and meaningful recovery from disordered eating. Matt holds a B.S. degree in Kinesiology from the Honors College at The University of Massachusetts Amherst, a master’s degree in Applied Exercise Physiology and Nutrition from Columbia University and was a dietetic intern at Boston’s Brigham and Women’s Hospital.