If athletes choose to use supplements despite the known risks, USADA has always recommended that athletes use only dietary supplements that have been certified by a third-party program that tests for substances prohibited in sport.
USADA currently recognizes NSF Certified for Sport® as the program best suited for athletes to reduce the risk from supplements.
Using an NSF Certified for Sport® product significantly reduces, but does not necessarily eliminate, the chance of testing positive and being sanctioned. Under the rules, if an athlete tests positive and establishes the source as a contaminated NSF Certified for Sport® product, the athlete could get a much-reduced sanction, but there likely would still be a consequence.
This is an necessary category.