Is fluoride in water bad for you? Some top questions, answered
There have been a lot of questions about fluoride since the Health and Human Services Secretary Robert F. Kennedy called for it to be removed from the water supply. But is fluoride actually good or bad for you? Dr. Mallika Marshall answers common questions about fluoride.
What is fluoride?
Fluoride is a mineral that occurs naturally in many foods and water.
Dentists and healthcare providers have been promoting the use of fluoride to help strengthen teeth and reduce the risk of cavities for years. That's because it makes your tooth enamel more resistant to acids and can also help reverse early decay by remineralizing the enamel.
Now, most toothpastes and mouthwashes contain a minimal amount of fluoride. There are fluoride treatments available from most dentists, where they apply it directly to your teeth.
When should people start using fluoride?
The Cleveland Clinic recommends that infants starting at six months, through teenagers at age 16, should use fluoride.
However, you want to be careful that young children don't swallow too much toothpaste, so follow your pediatrician's recommendations on how much to use. The American Dental Association, or ADA, recommends using a pea-sized amount during each brushing and avoiding fluoride mouthwashes until children are above the age of six.
Fluoride also benefits adults, specifically those with gum disease, a history of tooth decay, dry mouth, and people with crowns, braces, or dentures.
When did we start adding fluoride to our public water supply?
Before the 1930s, dental decay, cavities, and infections were incredibly common, and many children lost teeth.
Researchers found that people had less tooth decay in areas where fluoride was naturally present in water. So, the government started adding fluoride to public water supplies, and tooth decay levels fell dramatically.
Johns Hopkins Bloomberg School of Public Health emphasizes that fluoride is not a pollutant.
The CDC declared water fluoridation one of the 20th century's greatest public health achievements.
Is fluoride bad for kids' brain development?
Fluoride can cause side effects at very high dosages. For example, people who ingest too much fluoride can get tooth discoloration or spots on their teeth.
There has been some concern that high levels of fluoride may be associated with lower IQ scores in children, but more research needs to be done in this area. The ADA says that fluoride use in children can help prevent white streaks from appearing on tooth enamel through their developmental years.
It's highly unlikely that anyone would reach fluoride levels that can cause problems with over-the-counter dental hygiene products or from the water supply.
Why would removing fluoride from the water supply be a problem?
Utah became the first state to ban fluoride in its water starting on May 7, 2025. We have discussed the benefits of fluoride and the risks of tooth decay.
Many people in this country, especially those who live in rural or low-income areas, don't have access to routine dental care or brush regularly with fluoride toothpaste.
Dr. Mallika Marshall said she has taken care of a lot of immigrants in urgent care who come from places that don't have fluoride in the water supply, and has seen many young kids with horrible cavities, even in their front teeth.
Tooth and gum disease can be painful, affect one's ability to speak, eat, and sleep, and alter one's appearance, which can impact one's self-esteem. It's not just bad teeth: Tooth decay and gum disease are now being linked to heart disease and other chronic illnesses.
