The case revolves around Hans Knauss, an experienced alpine skier who tested positive for the prohibited substance norandrosterone during the FIS Alpine World Cup Downhill competition in Lake Louise, Canada, on November 27, 2004. The substance was confirmed in both his A and B samples, with further testing indicating an exogenous origin. Knauss attributed the positive result to contaminated nutritional supplements, specifically "Super Complete Capsules" from Ultimate Nutrition, which contained norandrostendione, a precursor to norandrosterone. He claimed he was unaware of the contamination and had taken steps to verify the supplement's safety, including consulting the supplier. The International Ski Federation (FIS) acknowledged the likely source of the substance but found Knauss negligent, given widespread warnings about supplement contamination. As an experienced athlete with access to anti-doping information, he was expected to exercise utmost caution. While the FIS recognized his lack of intent and cooperation in filing a criminal complaint against the supplement supplier, it deemed his actions insufficient for a full reduction under "no significant fault or negligence." The FIS reduced his two-year suspension but emphasized that his assistance did not fully meet the criteria for further leniency under anti-doping rules. The Court of Arbitration for Sport (CAS) upheld the FIS decision, reinforcing that athletes bear responsibility for supplement use, especially given publicized contamination risks. The panel noted that while Knauss demonstrated some due diligence, his failure to adhere to recommended supplements from his association constituted negligence. The CAS also rejected the argument that his criminal complaint warranted additional sanction reduction, as it did not directly aid in uncovering intentional doping under anti-doping regulations. The case underscored the principle that athletes must exercise extreme caution with supplements, even in the absence of intent, and highlighted the limitations in reducing sanctions based on peripheral cooperation. Knauss appealed the 18-month ineligibility sanction, arguing it was disproportionate given his clean record, age, and the fact that the substance did not enhance performance. He also highlighted the unique impact of the sanction on his skiing career due to the sport's racing calendar. The CAS upheld the sanction, emphasizing that the World Anti-Doping Code (WADC) and FIS rules limit the application of proportionality in doping cases to standardize sanctions across sports and athletes. The panel acknowledged the rigid approach but noted it serves the legitimate goal of harmonizing anti-doping penalties. Knauss claimed he took precautions by obtaining certification from the supplement manufacturer, but the panel found these measures insufficient, as he failed to seek independent expert advice despite warnings about contaminated supplements. The panel also noted that Ultimate Nutrition had a history of controversy, including legal action for selling products containing anabolic steroids. Knauss's regular consumption of the supplements, despite previous negative tests, did not absolve him of responsibility, as ingredient variations could lead to contamination. The panel concluded that Knauss did not exercise sufficient diligence, and the 18-month sanction was justified under the WADC and FIS rules. The decision underscores the strict liability principle in anti-doping regulations, where athletes bear responsibility for substances in their bodies regardless of intent or negligence. The CAS dismissed the appeal, ruled that each party would bear its own costs, and retained the CHF 500 court fee already paid by the appellant.