Fluoride Action Network

The TSCA Fluoride Trial, 2016 – present

Under the Toxic Substances Control Act (TSCA) of 1976, a group of non-profits and individuals petitioned the U.S. EPA in 2016 to end the addition of fluoridation chemicals into drinking water due to fluoride's neurotoxicity. The EPA rejected the petition. In response, the groups sued EPA in Federal Court in 2017. A 7-day trial was held in June 2020, with no ruling by the Court. The next phase of the trial is expected to be in January 2024.

Fluoride’s Neurotoxicity

The TSCA trial will provide evidence that fluoride is a developmental neurotoxicant at levels of exposure seen in the general population in water-fluoridated communities.

The following studies were online as of May 20, 2020.

Studies on Fluoride’s Effect on the Brain:

69 IQ studies (there were 52 IQ studies, reporting lower IQ due to fluoride exposure, published when the TSCA citizen petition was submitted in November 2016)

178 Human studies

303 Animal studies

39 Cell studies

58 Review studies

The above studies divided into categories:

75 studies on Behavior

260 studies on Cells & Tissues

• 249 studies on Cognitive Function

• 24 studies on Neurological Symptoms

Studies on fluoride’s effect on the human fetal brain

• He H, Cheng Z, Liu W. 1989. Effects of fluorine on the human fetus. Chinese Journal of Control of Endemic Diseases 1989;4(3):136-138. [English translation published in Fluoride 41(4):321–326. Translated by the Fluoride Action Network.)

• Du L, Wan C, Cao X, Liu J. 1992. The effect of fluorine on the developing human brain. Chinese Journal of Pathology 1992;21(4):218-20. [English translation published in Fluoride 2008;41(4):327–330 . Translated by the Fluoride Action Network.)

• Dong Z, Wan C, Liu J. 1993. Determination of the contents of amino-acid and monoamine neurotransmitters in fetal brains from a fluorosis-endemic area. Journal of Guiyang Medical College 18(4):241-45. (Translated by the Fluoride Action Network in 2012.)

• Yu Y, Wang W, Dong Z, et al. 1996. Neurotransmitter and receptor changes in the brains of fetuses from areas of endemic fluorosis. Chinese Journal of Endemiology 1996;15:257-259. [English translation published in Fluoride 2008;41(2):134–138.]

A snapshot of some of the studies.

2006: The National Research Council of  the National Academies published Fluoride in Drinking Water: A Scientific Review of EPA’s Standards,1 the most authoritative review of fluoride’s toxicity. It stated unequivocally that “fluorides have the ability to interfere with the functions of the brain and the body (page 222).”

2012: A Harvard-funded meta-analysis2 found that children ingesting higher levels of fluoride tested an average 7 IQ points lower in 26 out of 27 studies. Most had higher fluoride concentrations than in U.S. water, but many had total exposures to fluoride no more than what millions of Americans receive.

“Fluoride seems to fit in with lead, mercury,
and other poisons that cause chemical brain drain.”
Philippe Grandjean, MD, PhD, Harvard study co-author, Danish National Board of Health
consultant, co-editor of Environmental Health, author of over 500 scientific papers

2017: A National Institutes of Health (NIH) – funded study3 in Mexico covering 13 years found that every one half milligram per liter (mg/L) increase in fluoride in pregnant women’s urine – approximately the difference caused by ingestion of fluoridated water4 – was associated with a reduction of their children’s IQ by about 3 points. Leonardo Trasande, a leading physician unaffiliated with the study, said it “raises serious concerns about fluoride supplementation in water.”5

2018: A Canadian study6 found iodine-deficient adults (nearly 18% of the population) with higher fluoride levels had a greater risk of hypothyroidism (known to be linked to lower IQs). Author Ashley Malin said “I have grave concerns about the health effects of fluoride exposure.”7

2019: Another NIH-funded study8 in JAMA Pediatrics found every 1 mg/L increase in fluoride in Canadian pregnant women’s urine was linked to a 4.5 decrease in IQ in their male children. The physician editor of JAMA Pediatrics said “I would not have my wife drink fluoridated water9 if she was pregnant.

2019: A Canadian study10 found a nearly 300% higher risk of ADHD for children living in fluoridated areas.This reinforced earlier studies linking fluoride to ADHD in Mexico (2018)11 and  the U.S. (2015).12

2019: Another NIH-funded study13 in Canada found that babies fed formula mixed with fluoridated water averaged 4 IQ points less than those mixed with non-fluoridated water. Losses of non-verbal IQ were even more serious, an average of 9 points.

2019: A systematic review of 149 human studies and 339 animal studies by the U.S. National Toxicology Program14 concluded that “fluoride is presumed to be a cognitive neurodevelopmental hazard to humans.” The report is still in draft form, but NTP also said there is little chance they will change their finding.


1. National Research Council. 2006. Fluoride in Drinking Water: A Scientific Review of EPA’s Standards.  p. 222. The National Academies Press.

2. Choi AL, Sun G, Zhang Y, Grandjean P. 2012. Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-­Analysis. Environmental Health Perspectives, July 20.

2a. Grandjean quote. 2012. Impact of fluoride on neurological development in children. Featured news story, Harvard  T.H. Chan School of Public Health. Sept.

3. Bashash M, Thomas D, Hu H, Martinez-Mier EA, Sanchez BN, Basu N, Peterson KE, Ettinger AS, Wright R, Zhang Z, Liu Y, Schnaas L, Mercado-García A, Téllez-Rojo MM, Hernández-Avila M. 2017.  Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-­12 Years of Age in Mexico. Environmental Health Perspectives, Sept. 19.

4. Till C, Green R, Grundy JG, Hornung R, Neufeld R, Martinez-Mier A, Ayotte P, Muckle G, Lamphear B. 2018. Community Water Fluoridation and Urinary Fluoride Concentrations in a National Sample of Pregnant Women in Canada. Environmental Health Perspectives, Oct. 10.

5. Dovey D. 2017. Children’s IQ Could be Lowered by Mothers Drinking Tap Water While Pregnant. Newsweek, Sept. 19.

6. Malin AJ, Riddell J, McCague H, Till C. 2018. Fluoride Exposure and Thyroid Function Among Adults Living in Canada: Effect Modification by Iodine Status. Environment International, Dec;121(Pt 1):667-674.

7. Bienkowski B. 2018. We Add It to Drinking Water for Our Teeth – But is Fluoride Hurting Us? Environmental Health News, Oct. 10.

8. Green R, Lanphear B, Hornung R, Flora D, Martinez-Mier EA, Neufeld R, Ayotte P, Muckle G, Till C. 2019.  Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada. JAMA Pediatrics, Aug. 19.

9. Guarino B. 2019. Study Raises Questions About Fluoride and Children’s IQ. Washington Post, Aug. 20.

10. Riddell JK, Malin AJ, Flora D, McCague H, Till C. 2019. Association of Water Fluoride and Urinary Fluoride Concentrations with Attention Deficit Hyperactivity Disorder in Canadian Youth. Environment International, Dec;133, Part B, 105190.

11. Bashash M, Marchand M, Hu H, Till C, Martinex-Mier A, Sanchez BN, Basu N, Peterson KE, Green R, Schnaas L, Mercado-Garcia A, Hernandez-Avila M, Tellez-Rojo MM. 2018. Prenatal Fluoride Exposure and Attention Deficit Hyperactivity Disorder (ADHD) Symptoms in Children at 6-­12 Years of Age in Mexico City. Environment International, Dec;121(1):658-666.

12. Malin AJ, Till C. 2015.  Exposure to Fluoridated Water and Attention Deficit Hyperactivity Disorder Prevalence Among Children and Adolescents in the United States: An Ecological Association. Environmental Health, Feb.

13. Till C, Green R, Flora D, Hornung R, Martinez-Mier EA, Blazer M, Farmus L, Ayotte P, Muckle G, Lanphear B. 2020. Fluoride Exposure From Infant Formula and Child IQ in a Canadian Birth Cohort. Environment International, Jan. (originally issued online in Nov 2019).

14. Taylor K, Bucher J, Rooney A, Walker V, Wilson CJ, et al. 2019.  Draft NTP Monograph on the Systematic Review of the Fluoride Exposure and Neurodevelopmental and Cognitive Health Effects. National Toxicology Program, Oct 22.

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