FDA seeks to remove ingestible fluoride products | Image credit: Contemporary Pediatrics

On May 13, 2025, the FDA and US Health and Human Services' (HHS) secretary Robert F. Kennedy, Jr. announced the federal agency will begin taking steps to remove ingestible fluoride prescription drug products for children from the market, citing alterations to the gut microbiome and associations with thyroid disorders, among others.¹

According to the press release, the agency stated that, unlike fluoride-containing toothpastes or fluoride rinses—for which the FDA regulates "most products" according to an article from The Associated Press²—prescription drug products are ingested and have "never been approved by the FDA." The federal administration also stated in the press release that ingested fluoride has been shown to alter the gut microbiome. Given the early development of the microbiome in childhood, the FDA classified this impact as a "magnified concern."¹

"The best way to prevent cavities in children is by avoiding excessive sugar intake and good dental hygiene, not by altering a child’s microbiome. For the same reason that fluoride may kill bacteria on teeth, it may also kill intestinal bacteria important for a child’s health,” said FDA Commissioner Marty Makary, MD, MPH, in a statement. “I am instructing our Center for Drug Evaluation and Research to evaluate the evidence regarding the risks of systemic fluoride exposure from FDA-regulated pediatric ingestible fluoride prescription drug products to better inform parents and the medical community on this emerging area. When it comes to children, we should err on the side of safety."

Systematic review: Fluoride effect on gut microbiota

According to a study published March 10, 2025, in Nutrition Reviews, investigators sought to explore the impacts of systemic fluoride on gut microbiota composition and abundance and associated functions, such as gene and metabolic regulation. The study authors wrote, "Fluoride can prevent dental caries by inhibiting demineralization and promoting remineralization of teeth while affecting the physiology of oral microbiota, thus inhibiting cellular enzymes. However, the effect of systemic fluoride on gut microbiota is unknown."³

The systematic review that included 49 studies of which 42 were conducted in animals, 4 in humans, and 3 in vitro. Among 2 human studies of dental fluorosis and 1 of patients with breast cancer, there were differences in gut microbial composition, with increased relative abundance of Acidobacteria and Proteobacteria, and decreased abundance of Firmicutes and Bacteroidetes, according to the study.

"An ex vivo study of human feces indicated that ≤ 2 mg L^–1 NaF might boost 'health-associated' taxa, but concentrations (≥ 10 mg L^–1 NaF) could increase the ratio of some unhealthy microbes after 24 hours," wrote the study investigators, who concluded high doses potentially could be detrimental to the microbiome. However, ≤ 2 mg L^–1 NaF had positive effects.

FDA planning safety review

In the announcement, the FDA set a goal date of October 31 to complete a safety review and public comment period for taking action in efforts to remove ingestible fluoride products from the market. The HHS plans to disseminate the best practices for dental hygiene in children that are "feasible, effective, and do not alter gut health," according to the press release.¹

While it was not immediately clear how the FDA would remove products from the market, as a formal withdrawal of medical products would require a process that could take years, The Associated Press reported that the agency will ask manufacturers to pull products voluntarily.²

American Dental Association (ADA)

The ADA's website lists key points on a page titled "Fluoride: Topical and Systemic Supplements," which was published on June 14, 2023, according to search results. The association recognizes the use of fluoride and community water fluoridation as safe and effective to prevent the decay of teeth in children and adults. The ADA lists that fluoride supplements can be prescribed for children aged 6 months to 16 years who are at higher risk for tooth decay and for those whose primary drinking water has a low fluoride concentration.⁵

The ADA also noted, "A potential risk of fluoride use is the development of fluorosis, which may occur when excess levels of fluoride are ingested during tooth development. Fluorosis varies in appearance from white striations to stained pitting of enamel."

References:

1. FDA begins action to remove ingestible fluoride prescription drug products for children from the market. FDA. Press release. May 13, 2025. Accessed May 13, 2025. https://content.govdelivery.com/accounts/USFDA/bulletins/3e036b3

2. Perrone M. FDA and RFK Jr. aim to remove ingestible fluoride products used to protect kids' teeth. The Associated Press. May 13, 2025. Accessed May 13, 2025. https://apnews.com/article/fluoride-fda-kennedy-cavities-teeth-water

3. Yasin M, Zohoori FV, Kumah EA, Subramanian M, Dean P, Orr CH, Effect of Fluoride on Gut Microbiota: A Systematic Review, Nutrition Reviews, 2025;, nuae202, https://doi.org/10.1093/nutrit/nuae202

4. Fluoride: Topical and Systemic Supplements. American Dental Association. June 14, 2023. Accessed May 13, 2025. https://www.ada.org/resources/ada-library/oral-health-topics/fluoride-topical-and-systemic-supplements