In many countries, the manufacturing of dietary supplements is not appropriately regulated by the government. This means that the ingredients on the inside may not match those listed on the outside of the box or package.

In the undeclared substances found in the supplement can include one that is prohibited under anti-doping regulations.

Studies have shown that as many as 20 % of supplements on sale to athletes can contain products that are not declared on the label but that could lead to a positive doping result. A large number of positive tests have been attributed to the misuse of supplements.