Multiple studies have claimed adverse cognitive effects in children with overexposure to fluoride. Most human studies so far have focused on fluoride effects on just IQ, but many animal studies have linked excess fluoride intake on brain damage to specific brain regions or systems.

While studies on human IQ and fluoride have mixed results, a compelling portion have indicated a negative correlation. Further studies that are more rigorous are necessary to get a better understanding as to how and to what extent fluoride is affecting cognition.​

Some possible mechanisms of damage that have been proposed are:

• oxidative stress increase
• neurotransmitter level abnormality
• morphological changes of neurons
• protein level decreases
• metabolic changes

Some brain structures that seem to be big targets of fluoride/have shown more damage are:

• hippocampus
• hypothalamus
• prefrontal cortex
• basal ganglia
• cerebellum