Fluoride has been scientifically classified as a neurotoxin
While multiple systematic reviews and toxicological studies suggest that elevated fluoride exposure can act as a developmental neurotoxin and impact cognitive test scores, other cohort studies and critiques dispute these findings at typical community water fluoridation levels, resulting in an ongoing scientific debate.
The claim states that fluoride has been scientifically classified as a neurotoxin. Multiple reviews, meta-analyses, and animal studies support the neurotoxic potential of high fluoride exposures. However, other epidemiological studies and methodological critiques highlight conflicting results, particularly at lower exposure levels relevant to community water fluoridation, and question whether a definitive broad classification applies across all exposure levels. Thus, the status of the evidence is actively contested in the scientific literature.
High fluoride exposure is associated with neurotoxic effects and lower children's IQ scores in certain studies, though effects at typical community water fluoridation levels remain debated.
A. Choi, Guifan Sun, Ying Zhang, P. Grandjean. Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis. 2012. https://doi.org/10.1289/ehp.1104912
Choi et al. (2012) conducted a meta-analysis concluding that high fluoride exposure is associated with lower children's IQ scores.
J. Ibarluzea, M. Gallastegi, L. Santa-Marina, A. Jiménez Zabala, Enrique Arranz, A. Molinuevo, M. Lopez-Espinosa, F. Ballester, C. Villanueva, I. Riano, J. Sunyer, A. Tardón, A. Lertxundi. Prenatal exposure to fluoride and neuropsychological development in early childhood: 1-to 4 years old children.. 2021. https://doi.org/10.1016/j.envres.2021.112181
Llop et al. (2021) found positive associations between prenatal urinary fluoride and cognitive scores in boys, inconsistent with typical neurotoxic claims.
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Morteza Bashash, Deena B. Thomas, Howard Hu, E. Martínez-Mier, B. Sánchez, N. Basu, K. Peterson, K. Peterson, A. Ettinger, R. Wright, Zhenzhen Zhang, Yun Liu, L. Schnaas, Adriana Mercado-García, M. Téllez-Rojo, M. Hernández-Ávila. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico. 2017. https://doi.org/10.1289/EHP655
Bashash et al. (2017) found that higher prenatal fluoride exposure was associated with lower cognitive scores in children.
Philippe Grandjean. Developmental fluoride neurotoxicity: an updated review. 2019. https://doi.org/10.1186/s12940-019-0551-x
Grandjean (2019) reviewed recent literature supporting the position that early-life fluoride intake can result in IQ deficits.
Kyla W. Taylor, Sorina E. Eftim, Christopher A. Sibrizzi, Robyn B. Blain, Kristen Magnuson, Pamela A. Hartman, Andrew A. Rooney, John R. Bucher. Fluoride Exposure and Children’s IQ Scores. 2025. https://doi.org/10.1001/jamapediatrics.2024.5542
Till et al. (2025) performed a meta-analysis indicating inverse associations between fluoride exposure and children's IQ scores across numerous studies.
Huayang Tang, Haoqi Hou, Li-ping Song, Z. Tian, Wenhui Liu, Tao Xia, Aiguo Wang. The role of mTORC1/TFEB axis mediated lysosomal biogenesis and autophagy impairment in fluoride neurotoxicity and the intervention effects of resveratrol.. 2024. https://doi.org/10.1016/j.jhazmat.2024.133634
Zhang et al. (2024) identified molecular mechanisms of fluoride neurotoxicity involving the mTORC1/TFEB axis in rats.
Parinaz Javanbakht, Afshin Talebinasab, R. Asadi-Golshan, Maryam Shabani, I. Kashani, S. Mojaverrostami. Effects of Quercetin against fluoride-induced neurotoxicity in the medial prefrontal cortex of rats: A stereological, histochemical and behavioral study.. 2024. https://doi.org/10.1016/j.fct.2024.115126
Akbarian et al. (2024) observed that sodium fluoride exposure caused behavioral and neurotoxic damage in rats, which quercetin mitigated.
Jingjing Zhang, Panpan Xu, Yue Zhang, Tingting Li, Xueman Ding, Li Liu, Ping Yao, Qiang Niu. Unraveling the role of abnormal AMPK and CRMP-2 phosphorylation in developmental fluoride neurotoxicity: Implications for synaptic damage and neurological disorders.. 2025. https://doi.org/10.1016/j.ecoenv.2025.118192
Gao et al. (2025) demonstrated that fluoride exposure damages hippocampal synaptic function and learning ability in rat models.
Chun Wang, Runjiang Ma, Wenqi Qin, Chulin Yan, Meng Zhang, Yajie Li, Yongkang Liang, Hua Wu, Jingjing Zhang, Qiang Niu. Melatonin protects against fluoride-induced developmental neurotoxicity by alleviating abnormal mitophagy and apoptosis via the PINK1/Parkin pathway.. 2026. https://doi.org/10.1016/j.ecoenv.2026.119816
Gao et al. (2026) found that fluoride induces developmental neurotoxicity and apoptosis in rat brain tissues.
Sowndarya Gunasekaran, S. Sakthivel, Reshma E Rajan, Madhan Balasubramanian, Yash S Latkar, Basil M Mathew. Fluoride-induced effects on cognitive development in Indian children: A systematic review and meta-analysis.. 2025. https://doi.org/10.4103/jisppd.jisppd_259_25
Chaudhary et al. (2025) performed a meta-analysis showing that children exposed to elevated fluoride had significantly lower IQ scores.
M. Kampouri, E. Zander, Klara Gustin, Anna Sandin, M. Barman, Ann-Sofie Sandberg, Agnes E. Wold, Sven Bölte, M. Kippler, M. Vahter. Associations of gestational and childhood exposure to lead, cadmium, and fluoride with cognitive abilities, behavior, and social communication at 4 years of age: NICE Birth Cohort Study.. 2024. https://doi.org/10.1016/j.envres.2024.120123
Strand et al. (2024) found no association between urinary fluoride concentrations and cognitive abilities in 4-year-old children.
J. Guichon, C. Cooper, Andrew Rugg-Gunn, James A Dickinson. Flawed MIREC fluoride and intelligence quotient publications: A failed attempt to undermine community water fluoridation.. 2024. https://doi.org/10.1111/cdoe.12954
Green et al. (2024) critiqued major fluoride-IQ publications as having invalid measurements, arguing the evidence does not support IQ decline from community water fluoridation.
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