May 21, 2025 — Until recently, you probably hadn’t thought much about fluoride. It’s been added to public water supplies since the 1940s to help prevent cavities. The CDC named water fluoridation one of the “10 Great Public Health Achievements” of the 20th century.
Now headlines are calling its safety into question. In January, a large study review linked high doses to lower IQs in children. This spring, Utah and Florida banned fluoride in drinking water. And last week, the FDA announced it would remove prescription fluoride supplements — for children at high risk of tooth decay — from the market. Suddenly, the cavity-fighting mineral has seemingly been deemed dangerous.
What’s going on?
Newly Controversial
Activists have warned for decades about potential risks of fluoride, even though research shows harmful effects only at very high doses. With the Trump administration, those voices have been amplified, starting with Secretary of Health and Human Services Robert F. Kennedy Jr. Before the election in November, he called fluoride an “industrial waste” linked to numerous health risks — claims that have been widely discredited by scientific research. His campaign against fluoride follows similar uproars over vaccines and autism.
“We need to be judicious about the evidence and not just throw science out the window,” said Kevin Klatt, PhD, a research scientist at the University of California, Berkeley. “If you do, you get, essentially, the biases of an administration deciding what policy and regulations will be. It can lead to health claims that aren’t true.”
This public confusion can have a chilling effect. If you read only the headlines, you might assume that fluoride is simply dangerous.
“We’re seeing more and more people looking for non-fluoride toothpaste, refusing topical applications in dental offices,” said Scott Tomar, DMD, DrPh, the American Dental Association’s spokesperson on community water fluoridation. “They don’t know what the issue is. They just know they heard something, somewhere, about fluoride being bad.”
And then there’s the question of what harms might come if we move away from fluoride, said David Andrews, PhD. He’s the acting chief science officer at the Environmental Working Group, a nonprofit environmental research and advocacy organization. Community fluoridation tends to be most helpful to children without access to regular dental care — but “the focus is on the fluoride and not the dental care and dental coverage,” Andrews said. “I’m very concerned about the impact of ending fluoridation without also increasing support for dental coverage.”
It’s All About the Dose
Much of the debate about fluoride comes down to how much you’re exposed to. Over the years, recommended fluoride levels in water have been lowered. Today the CDC considers 0.7 milligrams per liter to be optimal, while the World Health Organization’s guideline is 1.5 milligrams per liter (mg/L).
January’s big review of studies, published in JAMA Pediatrics, found a clear link between fluoride levels in water and lower IQ in children starting at concentrations of 1.5 mg/L — more than twice the CDC recommendation.
Researchers did see effects below 1.5 mg/L, wrote lead author Kyla Taylor, PhD, in an email, but the trend at those lower levels was less clear. That’s because there were relatively few data points for water fluoride, making it harder to find statistically meaningful effects. Many more data points existed for fluoride in urine, which reflects total exposure from all sources — not just water but also toothpaste and things like black tea and coffee. All this makes it harder to detect a reliable pattern between water fluoride and IQ, especially at lower levels.
A monograph produced by the National Toxicology Program in 2024 had similar findings: Exposure at higher levels, above 1.5 mg/L, was consistently linked with lower IQ scores in children. The report stressed that there wasn’t enough data to determine if low levels in water posed a similar risk.
Almost 12 million Americans drink public water with naturally occurring fluoride above 0.7 mg/L. This is a cause for concern, but there are no large-scale efforts to lower those levels.
What to Do
As an adult, you’re safe — there’s no evidence that shows fluoride poses any risk to you. And unless your family’s water supply contains significantly more than 0.7 mg/L of fluoride, your children’s risk is low, too.
But there are two circumstances that call for a closer look:
- If you worry about naturally occurring fluoride in your tap water, contact your local water provider for details. The EPA requires community water systems to alert their customers if levels hit 2 mg/L or higher. Using well water? Get a sample tested —check with your local health department to find a state-certified lab near you. Should the results be worrisome, you can install filters to remove the fluoride. (Home test kits are available, but research suggests they may not be accurate.)
- If you’re formula-feeding an infant and concerned about fluoride in your tap water, use fluoride-free water (such as purified or distilled) to mix it. Breastfeeding? Drinking fluoridated water is fine — concentrations in breast milk are so low, they’re sometimes undetectable.
