The Potentially Harmful Ingredients in Sports Supplements

Sports supplement usage is widespread but sometimes contain banned substances and mislabeled ingredients that could cause adverse health events, including liver damage and cardiac arrest.

Sports supplement usage is widespread in many sports—from running and cycling, to baseball and bodybuilding—and it’s not limited to elite athletes and professionals any more. Students, recreational athletes and ‘weekend warriors’ are a significant segment of the fast-growing sports nutrition market. But dietary and sports supplements sometimes contain banned substances and mislabeled ingredients—just ask the many elite athletes who’ve been suspended from their sports due to inadvertent doping. While suspension from competition is a concern for elite athletes, it’s not the greatest risk for most athletes and consumers.

In the last 10 years, I’ve worked closely with researchers from Harvard Medical School, the National Center for Natural Products Research (NCNPR) at the University of Mississippi, and the National Institute for Public Health and the Environment in the Netherlands (RIVM). In our published research, we’ve found that some supplements in the global market contain harmful ingredients and contaminants, including drugs and untested compounds that are not always listed on the label. We’ve identified ingredients in supplements that can cause adverse health events, including liver damage, cardiac arrest and even death. The research also revealed untested and potentially harmful compounds such as DMAA, DEPEA, DMBA and oxilofrine in over-the-counter supplements1.

These ingredients are often deceptively labeled as botanical extracts such as geranium oil, dendrobium extract and Poochung tea extract – making it difficult for consumers and athletes to choose a supplement based on the ingredient listings alone.

While most manufacturers are committed to ensuring quality and safety, there are a few irresponsible and unscrupulous supplement makers out there. As our research demonstrates, their actions can put consumers’ health at risk.


In 2016, we found the unapproved pharmaceutical stimulant oxilofrine in 14 over-the-counter dietary supplement products. Our research was published in the peer-reviewed journal Drug Testing and Analysis. Oxilofrine is easily disguised or unlisted on labels, often as ‘methylsynephrine’ or ‘extract of Acacia rigidula’, posing serious health risks to consumers.

According to the research, 26 adverse events have been reported in the Netherlands linked to supplements containing oxilofrine. These side effects included nausea and vomiting, tachycardia, chest pain and cardiac arrest.


The chemical structures of DMBA and DMAA. Note that DMBA has one chiral center and that DMAA has two chiral centers.

In 2014, we found an unapproved synthetic stimulant (1, 3-Dimethylbutylamine or DMBA) in 12 over-the-counter dietary supplements. The findings were published in the peer-reviewed journal Drug Testing and Analysis.

The chemical structure of DMBA is similar to other banned stimulants, DMAA and ephedrine. DMAA was banned by regulatory agencies in the United States, United Kingdom, The Netherlands, Brazil and elsewhere because of its links to negative health events such as strokes, heart failure and sudden death. There are no known safety studies on DMBA and its health effects are entirely unknown.


In 2013, we worked with the U.S. Army Research Institute of Environmental Medicine (USARIEM), to determine that 1,3 dimethylamylamine, also known as DMAA, is not ‘natural’ in origin and should not be used as an ingredient in dietary supplements. The findings supported research conducted by academic laboratories around the world.

Several sports supplement makers have tried to market DMAA as a natural constituent of geranium or its extract, but there is no credible scientific evidence to support that claim.


In 2013, we found evidence of an emerging and potentially harmful adulterant called N,alpha-diethylphenylethylamine (N,a-DEPEA) in a popular dietary supplement product. This substance has a chemical structure similar to methamphetamine and products containing this have been linked to several failed drug tests. DEPEA’s addictive and pharmacological properties are unknown.

Independent Testing and Certification

As these high-profile cases illustrate, the actions of a few bad manufacturers can irrevocably harm brand reputation and reflect negatively on the entire supplement industry. Fortunately, reputable companies can seize this opportunity to showcase their products’ safety, verify label claims and differentiate themselves in the marketplace. Independent third-party certification of dietary and sports supplements and ingredients helps weed out illegal and non-compliant products from the marketplace.

When consumers see the NSF International certification mark on a package, they can be sure those vitamins and supplements have been independently tested for harmful levels of specific contaminants like lead and arsenic. NSF certification also means the product has been tested to make sure the ingredients listed on the package are actually in the product. Tested, certified, safer—that’s what the NSF mark means.


John Travis has more than 20 years of experience as an analytical chemist specialising in the analysis of dietary supplements. As Senior Research Scientist at global public health organisation NSF International, Travis analyses hundreds of dietary supplement products each year for various contaminants, emerging drugs and harmful compounds. He is a subject matter expert on athletic banned substances and was instrumental in the development of the screening methods used for the NSF International Certified for Sport® program, which now screens products for more than 270 banned substances on the World Anti-Doping Agency, National Football League, Major League Baseball and National Collegiate Athletic Association lists.Travis is currently involved with the analysis of pharmaceutical agents and illicit drugs, stimulants and other prohibited substances as both adulterants and contaminants in dietary supplements and functional foods, co-authoring scientific papers on ingredients of concern including stimulants drugs DMAA, DEPEA and DMBA found in dietary supplements.

1.       Cohen, P. A., Avula, B., Venhuis, B., Travis, J. C., Wang, Y.-H., and Khan, I. A. 'Pharmaceutical doses of the banned stimulant oxilofrine found in dietary supplements sold in the USA.' Drug Test. Analysis, (2016) doi: 10.1002/dta.1976.

To learn more about potential adulteration of sports nutrition products, listen to our podcast with John here.

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