Extreme caution is recommended regarding supplement use.

The use of dietary supplements by athletes is a concern because in many countries the manufacturing and labeling of supplements may not follow strict rules, which may lead to a supplement containing an undeclared substance that is prohibited under anti-doping regulations. A significant number of positive tests have been attributed to the misuse of supplements and taking a poorly labeled dietary supplement is not an adequate defense in a doping hearing.

The World Anti-Doping Agency (WADA) is not involved in the testing of dietary/nutritional supplements.

The Laboratory Code of Ethics, in the International Standard for Laboratories (Section 4.4 of Annex B), states that WADA-accredited laboratories shall not engage in analyzing commercial material or preparations (e.g. dietary supplements) unless specifically requested by an Anti-Doping Organization as part of a doping case investigation. The Laboratory shall not provide results, documentation or advice that, in any way, suggests endorsement of products or services.