Fluoride Action Network

People’s Pharmacy: Does fluoride in water affect thyroid function?

Spokesman Review | May 9, 2023 | By Joe Graedon, M.S., and Teresa Graedon, Ph.D.
Posted on May 9th, 2023

Q. I have Hashimoto’s autoimmune hypothyroid disease. I did not feel well taking just Synthroid. When I started taking Unithroid along with a small dose of Cytomel, that worked much better for me.

Most doctors only test the TSH level and then treat that number. Testing free T4 and free T3 is a much better indicator of real thyroid activity.

I have heard that fluoride has a negative effect on the thyroid. Is that true?

A. Fluoride remains a controversial water treatment. On the one hand, dentists promote the use of fluoridated water and toothpaste to prevent tooth decay.

On the other hand, there is some data linking exposure to high levels of fluoride with an increased risk for hypothyroidism. A systematic analysis of 10 studies concluded: “The study has shown a positive correlation between fluoride and hypothyroidism, which is an alarming issue.” (Indian Journal of Dental Research, May-June 2018).

A recent study from Canada found that: “In this Canadian pregnancy and birth cohort, fluoride in drinking water was associated with risk of primary hypothyroidism in pregnant women.” (Science of the Total Environment, April 15, 2023) Scientists believe that fluoride may interfere with the deiodinase enzymes that convert inactive T4 hormone to active T3.

*Original full-text article online at: https://www.spokesman.com/stories/2023/may/09/peoples-pharmacy-does-fluoride-in-water-affect-thy/