As of September 2017, a total of 58 studies have investigated the relationship between fluoride and human intelligence, and over 40 studies have investigated the relationship fluoride and learning/memory in animals. Of these investigations, 51 of the 58 human studies have found that elevated fluoride exposure is associated with reduced IQ, while 45 animal studies have found that fluoride exposure impairs the learning and/or memory capacity of animals. The human studies, which are based on IQ examinations of over 12,000 children, provide compelling evidence that fluoride exposure during the early years of life can damage a child’s developing brain.