ORIGINAL ARTICLE Would the Use of Safe, Cost-Effective tDCS Tackle Rather than Cause Unfairness in Sports? Laura Sophie Imperatori 1 & Luke Milbourn 2 & Mirko Daniel Garasic 1,3 Received: 27 June 2018 /Accepted: 8 November 2018 # Springer Nature Switzerland AG 2018 Abstract Neuromodulation technologies like transcranial direct current stimulation (tDCS) might enable professional and amateur athletes to reach their respective levels of physical excellence in a safe, cost-effective, and fair manner. Key factors that may assist an athlete in achieving their potential usually include training for many years, often since childhood, and access to a high level of funding. If cost-effective neuromodulation based on tDCS lives up to its promises (regarding safety and efficacy), tDCS can help athletes to learn relevant skills more effectively and thus reach their respective levels of physical excellence more quickly, especially athletes with limited time and resources. Whilst dangerous, illegal drugs such as EPO and steroids can increase performance without training, current evidence suggests that tDCS assists an athlete in improving their performance in combi- nation with training. Given that the World Anti-Doping Association has not made any statement regarding the permissibility of tDCS, whilst access to and popularity of tDCS are constantly increasing, it is important to consider more in-depth if the use of tDCS can be justified. Here, we will outline three key criteria that any performance-enhancing measure must meet if its use can be considered ethical and permissible according to WADA requirements. tDCS must meet our requirements of safety, hard work from the athlete and accessibility. The preliminary evidence regarding its safety, its relatively low cost and the reasonable expectation, that long-term improvements can only be made if its application is paralleled by intense training, justifies its further research in the context of athletic performance enhancement. Moreover, we also consider its potential wider impact, especially how tDCS could help to level the playing field between amateur and elite athletes. Keywords tDCS . Sports . Athletic performance . Enhancement . Ergogenic aid . Doping Enhancement in Sports Like in all other human endeavours, athletes are striving to be the best they can be at their discipline. The goal of any athlete is to develop their full potential according to the Olympic motto BCitius, Altius, Fortius^ (Latin for BFaster, Higher, Stronger^), proposed by Pierre de Coubertin (1894). The main bounds on athletic performance are physiological limitations such as muscle strength or aerobic capacity, influenced by both genetic and environmental factors. These physiological limitations are not reached without years and years of high intensity training. However, being able to perform this high intensity training (i.e. to be able to push one’ s physiological boundaries) requires time, money and access to the right train- ing equipment at the right time. Illegal pharmacological per- formance enhancing drugs (PEDs) that can push an athlete well over his or her physiological limitations have long been part of the world of sports (Hackney 2017). The use of phar- macological doping substances may explain the last burst of performance occurring in the 1990s before a phase of stagna- tion, when stricter anti-doping regulations came into place (Berthelot et al. 2010). Since doping controls are stricter than they used to be, legal ergogenic aids and especially techno- logical advances that can enhance athletic performance in a safe manner started being sought after. Examples include sleep optimisation systems, hypoxic tents or the promising technology of transcranial direct current stimulation (tDCS) (Nitsche et al. 2008), which we are discussing here. As * Laura Sophie Imperatori laurasophie.imperatori@gmail.com 1 IMT School for Advanced Studies Lucca, Piazza San Francesco 19, 55100 Lucca, Italy 2 Independent Researcher, Via Terza delle Tagliate 252\A, 55100 Lucca, Italy 3 UNESCO Chair in Bioethics and Human Rights, Via degli Aldobrandeschi 190, 00163 Rome, Italy Journal of Cognitive Enhancement https://doi.org/10.1007/s41465-018-0113-0