March 13, 2020

Fluoridation’s Neurotoxicity

There is now no question that fluoride is neurotoxic, damaging the brain and central nervous system, as documented by hundreds of recent studies. It cannot be declared safe.

Here are short summaries of just a few studies:

2006: The National Research Council published Fluoride in Drinking Water,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.”

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 the Journal of the American Medical Association 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 water”9 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, Fluoride in Drinking Water, 2006, p. 222

2. Choi et al, Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis, Environmental Health Perspectives, July 20, 2012

3. Bashash et al, Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico, Environmental Health Perspectives, Sept. 19, 2017

4. Till et al, Community Water Fluoridation and Urinary Fluoride Concentrations in a National Sample of Pregnant Women in Canada, Environmental Health Perspectives, Oct. 10, 2018

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

6. Malin et al, Fluoride Exposure and Thyroid Function Among Adults Living in Canada: Effect Modification by Iodine Status, Environment International, Dec. 2018

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

8. Green et al, Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada, Journal of the American Medical Association Pediatrics, Aug. 19, 2019

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

10. Riddell et al, Association of Water Fluoride and Urinary Fluoride Concentrations with Attention Deficit Hyperactivity Disorder in Canadian Youth, Environment International, Dec. 2019

11. Bashash et al, Prenatal Fluoride Exposure and Attention Deficit Hyperactivity Disorder (ADHD) Symptoms in Children at 6-12 Years of Age in Mexico City, Environment International, Dec. 2018

12. Malin et al, Exposure to Fluoridated Water and Attention Deficit Hyperactivity Disorder Prevalence Among Children and Adolescents in the United States: An Ecological Association, Environmental Health, Feb. 27, 2015

13. Till et al, Fluoride Exposure From Infant Formula and Child IQ in a Canadian Birth Cohort, Environment International, Jan. 2020 (first issued online in 2019)

14. National Toxicology Program, Draft NTP Monograph on the Systematic Review of the Fluoride Exposure and Neurodevelopmental and Cognitive Health Effects, Sept. 6, 2019

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