Why do supplements need to be tested?

Sports supplements are frequently blamed by elite athletes when they test positive in a urine/blood drug test. Historically, high sensitivity testing of supplements has indicated that a significant proportion of these contain traces of substances that are considered prohibited by WADA. This has somewhat reinforced the athlete's claims about the origins of their positive urine/blood tests.

Only those products that have been tested using appropriately accredited methods (ISO 17025), at the appropriate detection limits for the relevant substances, should be considered suitable for regular "drug-free" use.