American swimmer Phelps' coach Bowman believes that "the skills in the pool are relatively stable, and the differences in skills among top athletes are not significant. In this situation, swimsuits will be a very important thing. And the head coach of the Italian national swimming team, Castagnetti, referred to shark skin as a "high-tech stimulant" in the swimming pool. Such voices are not uncommon, which means that in the eyes of some people, the use of 'shark skin', like stimulants, contains elements of unfair competition.

Moreover, only Speedo produces' shark skin ', which has led to dissatisfaction from other businesses, who believe that Speedo deliberately exaggerates the role of swimsuits and lures high-level athletes away from other sponsors. In April, several swimwear companies including Arena once again filed a complaint with the International Swimming Federation, claiming that 'shark skin' uses polyurethane fiber material that can increase buoyancy, violating the International Swimming Federation's policy of 'athletes are not allowed to use or wear any equipment that can increase speed, buoyancy, or endurance during the competition'. However, it was not supported by the International Swimming Federation.