A Study of Unintentional Doping in CAS Jurisprudence

Unintentional doping is when an athlete unknowingly breaches an anti-doping rule, typically because a prohibited substance enters their body through contaminated supplements, food, or medication. It is a complex area of doping law, operating on the principle of strict liability, meaning an athlete is held responsible regardless of their intent. The mere presence of a prohibited substance is enough to constitute a violation, carrying a 4-year ban. However, under Articles 10.2.2 and 10.6.1 of the World Anti-Doping Code (“WADC”), if the athlete can prove that the violation was unintentional, then the ban will be reduced to 2 years. In the WADC, it states that:

“the term “intentional” is meant to identify those Athletes or other Persons who engage in conduct which they knew constituted an anti-doping rule violation or knew that there was a significant risk that the conduct might constitute or result in an anti-doping rule violation and manifestly disregarded that risk”[1].

Accordingly, to establish unintentional use, an athlete must prove that a) they did not deliberately ingest the substance and/or b) did not act recklessly. They must demonstrate this on the balance of probabilities, meaning that it is more likely to have occurred than not. Further, in a significant number of cases at the Court of the Arbitration for Sport (“CAS”), the athlete has been unable to identify the source of the prohibited substance, or how it entered their body. This makes it even harder for the athlete to prove a lack of intention. In the WADC it states: “it is highly unlikely that in a doping case … an Athlete will be successful in proving that the Athlete acted unintentionally without establishing the source of the Prohibited Substance”[2].

But what does “highly unlikely” actually mean in practice? How does it affect the standard of proof? In this essay I review a range of diverse CAS decisions to understand what evidence athletes must provide to prove that they did not unintentionally consume prohibited substances, particularly when they are unable to identify the source of the substance.

Abdelrahman: A Narrow Corridor

The first case I will examine is the Abdelrahman decision[3]. In this case, the CAS panel deliberated whether Egyptian javelin thrower Ihab Abdelrahman had intentionally taken testosterone, a prohibited substance, after testing positive. The panel emphasised that athletes seeking to prove that they did not act deliberately or recklessly must support their claims with objective, verifiable evidence. The panel’s deliberation is “not confined to a binary choice: intention or non-intention”[4], meaning that they do not need to decide whether Abdelrahman intended to cheat or not. Rather, they are tasked with a specific legal question of a set standard: has the athlete presented sufficient evidence to show, on the balance of probabilities, that they did not intend to cheat?

Reviewing Abdelrahman’s evidence, there are clear concerns of inadequate documentation of supplement use and procedural errors in challenging his A and B samples. Most concerning, however, is that he failed to establish the source of the substance. He could not prove where it came from. However, as stated both in the WADC and repeated in by the panel in this case, the source of the substance is “not mandated in order to prove an absence of intent”[5]. While valuable, proof of the substance’s source is not required if the surrounding evidence and context strongly supports the athlete’s case. The evidence must be objective and based in the specific facts and actions of the case. If this kind of strong surrounding evidence is presented, then it “leaves the narrowest of corridors through which such athlete must pass to discharge the burden which lies upon him”[6].

Abdelrahman and his legal team were not able to meet this high standard of proof. The panel found that the explanations provided by the Appellant were “no more than theoretical possibilities”[7], mere speculations rather than objective evidence.

Lawson: A Broader Interpretation

Subsequent CAS decisions, such as Lawson, appear to have widened the principle of the “narrowest of corridors” in the Abdelrahman case, suggesting a lower standard of proof for the athlete when proving lack of intent[8]. Unlike in common law, CAS does not follow binding precedent and so panels are not required to follow past rulings. In the Lawson case, an American track-and-field athlete Jarrion Lawson tested positive for trenbolone, an anabolic steroid and prohibited substance used to boost growth of cattle. The athlete claimed the positive result came from eating contaminated meat at a restaurant. 

The CAS panel argued that it was scientifically impossible to prove whether the consumed steak contained hormone residues or not and so accepted Lawson’s arguments as a “reasonable possibility”[9]. They also put weight on how Lawson acted with transparency and took reasonable steps to trace and provide evidence, and so believed he provided a credible explanation. He was supported by his reputation and character, the panel citing evidence of his “impeccable history and attitude to ‘clean’ sport”[10]. While the panel acknowledged they could not “see into athletes’ souls”, they believed this wider conduct was important to acknowledge[11]. They concluded that it more than unfair and harsh to dismiss his efforts in obtaining supporting evidence.

However, the decision drew strong criticism. Jonathan Taylor, former chairman of the WADA Compliance Review Committee, disagreed with the low standard of proof applied to the athlete’s explanation.

“The fact that the athlete tested positive after eating hormone-treated meat is only more than mere circumstance if there is good evidence that the meat more likely than not contained sufficient trenbolone to cause the positive test, and here there was not”[12].

What Taylor is arguing here is that the CAS panel appeared to treat the athlete’s explanation - that the trenbolone originated from contaminated steak - as if it were established fact. By doing so, the panel showed undue sympathy to the athlete rather than critically evaluating whether there was clear and objective evidence to support his claim. In reality, the athlete has not proven the source of the substance, but has merely offered an unsubstantiated and vague possibility. Taylor also criticised the panel’s reliance on Lawson’s good character and after-the-fact behaviour, arguing that such traits do not consider hard evidence and are merely circumstantial. Taylor’s criticisms were later echoed in the CAS decision Iannone, where the arbitrators endorsed his reasoning that “the athlete cannot rely on simple protestations of innocence or mere speculation as to what must have happened but must instead adduce concrete and persuasive evidence” [13]. The panel identified cases like Lawson as outliers, noting that they appear to broaden the threshold of acceptable proof beyond what CAS traditionally allows.

Shayna Jack: Process over Precedent

As such, we can see that there is clear divergence in CAS jurisprudence on unintentional doping, particularly regarding how broadly or narrowly the burden on the athletes is interpreted. How should future CAS cases navigate these differences to consistently interpret the standard of proof for athletes? The Shayna Jack CAS decision presents an insightful solution[14]. Rather than focusing on the facts of past cases - which can be overly complex and technical - arbitrators should focus on the process of doping decisions. As the arbitrator in the case says, “the way in which arbitrators apply this method in a given case may be a matter of controversy, but as a process it appears to be in conformity with the Policy”[15]. The process begins with the science, considering the totality of the evidence, applying common sense and then evaluating the athlete’s credibility. An understanding of this process can create consistency and predictability in arbitral decisions.

The panel followed this process in the Jack decision. The athlete tested positive for ligandrol, a banned anabolic agent, and was given a 4-year suspension. She was unable to identify the source. The Panel noted that only “pharmacologically irrelevant” amounts of Ligandrol were found in her body that offered no proven performance benefit[16]. Further, the athlete commissioned a number of hair and urine tests (at considerable expense) which indicated no long-term usage. Considering her circumstances, they noted that there was no evidence of any drop in form before the relevant period, coming to the conclusion that “this was not the picture of a candidate looking for forbidden means of adding sprinting power”[17]. This led the panel to consider common sense. Why would an athlete at the peak of her performance choose to ingest a substance whose effectiveness has not been scientifically proven and offers no clear or proven performance benefit? The alleged intent in this case “require[s] not only unscrupulousness but also a high degree of foolishness”[18]. The panel then considered her character. While not intended to give weight to uncorroborated assertions, they noted “a mature awareness of the rules of her sport and the need not to endanger her career with ill-advised initiatives”[19]. This led the panel to conclude that she had unintentionally consumed the prohibited substance. Following the definition of ‘intentionality’ in Article 10.2.3, they found “that she did so innocently seems on balance more likely than that she either intended to take this Substance or was recklessly oblivious to the risk of contamination in the course of her activities”[20]. 

So what can we learn from this case? Unlike in the Abdelrahman and Lawson decisions, the athlete was able to provide strong, circumstantial evidence to support her claim. While there is a preference for direct evidence in CAS law (i.e. evidence of the source of the substance), what we can see emerge is that if direct evidence is not available, then strong circumstantial evidence is sufficient for an athlete to pass on the balance of probabilities. Additionally, it is interesting to see the arbitrator included the ‘athlete’s credibility’ in the outlined process, particularly following the previous criticism from Johnathan Taylor and the Iannone decision. While the arbitrator agrees that claims of innocence should not be accepted at face value or treated as evidence, they also note that it would be unrealistic to deny that an athlete’s ‘likeability’ can influence, to some degree, the arbitrator’s decision, as evidenced in previous decisions[21]. An athlete’s credibility can help to strengthen the overall case and contribute to a more well-rounded conclusion.

Concluding Thoughts

In summary, we have seen a clearer understanding of the jurisprudence emerge. Cases of unintentional doping require the athlete to prove on the balance of probabilities, that they acted neither a) with intention or b) recklessly. The athlete needs to provide strong, objective, evidence-based arguments that are not based on speculation or theory. In cases where the source is not identified, the standard of proof is much higher, but not impossible. It requires strong supporting circumstantial evidence to prove that all other alternative possibilities are considered. Additionally, the athlete’s credibility and demeanour can help to support and bolster the decision.

However, while these elements can be identified, this is not to suggest that CAS anti-doping jurisprudence is now settled or consistently applied. Although the Shayna Jack decision appeared to establish a framework, subsequent cases have not necessarily followed its approach. In the 2024 X vs World Athletics decision, the panel puts a much stronger emphasis on the role of direct evidence, continually returning to the issue that “the analysis of his food supplements remained inconclusive”[22]. This is a departure from the Jack case, which valued circumstantial evidence. Would it be the case that if the athlete had appeared before the arbitrator from the Jack panel, they may have received a different outcome?

While it is impossible to draft anti-doping rules that can enable panels to decide with perfect certainty whether an athlete has committed an offence, I remain concerned with the lack of consistency in decisions. I believe that this inconsistency is due to the highly fact-specific nature of these cases and a lack of binding precedent regarding following past decisions. Yet in an environment where a ban “could potentially have a career-ending effect”[23], athletes deserve a more consistent and predictable judicial framework.

References:

[1] World Ant-Doping Agency, World Anti-Doping Code (2027) art 10.2.3

[2] World Ant-Doping Agency, World Anti-Doping Code (2027), Comment under art 10.2.1

[3] Ihab Abdelrahman v Egyptian Anti-Doping Organization (EGY-NADO); World Anti-Doping Agency (WADA) v Ihab Abdelrahman & EGY-NADO (Court of Arbitration for Sport, CAS 2017/A/5016 & CAS 2017/A/5036, 18 December 2017).

[4] Abdelrahman (n 3) para 131.

[5] Abdelrahman (n 3) para 2.

[6] Abdelrahman (n 3) para 123.

[7] Abdelrahman (n 3) para 129.

[8] Jarrion Lawson v International Association of Athletics Federations (IAAF) (Court of Arbitration for Sport, CAS 2019/A/6313, 6 March 2020).

[9] Lawson vs IAAF (n 8) para 65.

[10] Lawson vs IAAF (n 8) para 87.

[11] Lawson vs IAAF (n 8) para 88.

[12] Johnathan Taylor, 'Assessing contamination and thresholds under the World Anti-Doping Code: an advocate’s view on Lawson v IAAF (CAS 2019/A/6313)', LawinSport (Blog Post, 24th April 2020)

< https://www.lawinsport.com/topics/item/an-advocate-s-view-on-lawson-v-iaaf-cas-2019-a-6313>

[13] Andrea Iannone v. Fédération Internationale de Motocyclisme (FIM); World Anti-Doping Agency (WADA) v FIM and Andrea Iannone (Court of Arbitration for Sport, CAS 2020/A/6978 & 7068, 10 November 2020)

[14] Shayna Jack v FINA and Sport Integrity Australia v Shayna Jack (Court of Arbitration for Sport, CAS 2021/A/7579 & 7580, 16 December 2021).

[15] Jack (n 15) para 157.

[16] Jack (n 15) para 30.

[17] Jack (n 15) para 163.

[18] Jack (n 15) para 169.

[19] Jack (n 15) para 172.

[20] Jack (n 15) para 180.

[21] The arbitrator refers to the Lawson decision and the Jamnicky decision (CAS 2019/A/6443), where three-member tribunals were clearly influenced by the ‘personal charm’ of the appellants.

[22] X v World Athletics (Court of Arbitration for Sport, CAS 2024/A/10273, 24 March 2025)

[23] X v World Athletics (n 22) para 118.