September 2021

· 5 min read

Sports Supplements: The Basics on Contaminants and Unintended Doping

Sports supplements may contain many helpful ingredients such as minerals or amino acids. Unfortunately, they may also contain hazardous contaminants. Our experts tell all.
Close up of woman eating a protein bar - Sports Supplements Contaminants and Unintended Doping | NSF International

When browsing through aisles of vitamins and supplements, it’s easy to grab whichever product makes the best claim and fits best within your budget. But what you might not know is that sports supplements can contain unintended or unlisted ingredients that may be harmful to your health.

The good news is that supplements can be beneficial as long as you’re aware of which ingredients to avoid, says our expert, John Travis, Technical Leader for NSF International’s Certified for Sport® program.

The first step is to understand what a contaminant is.

A contaminant is a chemical, physical or biological component of a product that was intentionally or unintentionally added to the product. The presence of a contaminant typically results in reduced purity. Examples include heavy metals, pesticides, residual solvents, stimulants and natural toxins.

There may or may not be a health risk associated with contaminants in a product. Health risk is determined by considering the type of contaminant, how much of it is in each capsule or tablet, and the recommended daily dose.

A contaminant is a chemical, physical or biological component of a product that was intentionally or unintentionally added to the product. The presence of a contaminant typically results in reduced purity. Examples include heavy metals, pesticides residual solvents, stimulants and natural toxins.

How Do Contaminants Get Into Supplements?

There are two ways a contaminant can get into a supplement — intentionally or unintentionally, says John.

  1. 1

    Unintentional

    Contaminants that naturally occur in soil or have been used to treat plants can make their way into products. They may be introduced during the production of an ingredient, such as residual pesticides that were used on plants to control insect pests or prevent toxic fungus from growing on a plant, or from additives used in manufacturing the ingredient.

    For example, Echinacea, which is a plant-based dietary supplement used to boost the immune system, could accidentally contain small amounts of toxic chemicals that landed on the plants by drift from nearby plants that have been treated with pesticides or other toxic chemicals.

    Another example is the sweeteners found in the stevia leaf. They are extracted to prevent contact with other compounds in the stevia leaf that have been found to harmfully affect the kidneys or introduce risk of reproductive toxicity.

  2. 2

    Intentional

    Some manufacturers adulterate their product with what they know to be illegal performance-enhancing substances to create a seemingly greater beneficial impact of the supplement on the user. This can sometimes be called unintentional doping for professional athletes who unknowingly take adulterated products.

    A common example of supplement adulteration is the addition of unlisted or hidden stimulants such as caffeine or ephedrine to various herbal tonics to enhance the supplement’s effects.

How to Protect Yourself Against Contaminants in Dietary Supplements

The best way is to make sure the product has been tested for contaminants. Knowing the product has been tested for contaminants, such as toxins or heavy metals, provides you assurance of a safer product, John says. Beware of supplements that lack independent certification. Certification by accredited third-party organizations, like NSF International, is the easiest and best way to know that what is on the label is what is in the bottle and to protect yourself against taking supplements with potentially harmful or undeclared ingredients. NSF certified products have been made in facilities inspected by NSF and they have been tested in NSF labs.

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