Last Editorial Review: 6/11/2021
Other Name(s):

Acidulated Phosphate Fluoride, Atomic number 9, Calcarea Fluorica, F, Fluorophosphate, Fluorure, Fluorure d'Hydrogène, Fluorure de Phosphate Acidulé, Fluorure de Sodium, Fluorure Stanneux, Fluoruro, Hydrogen Fluoride, Monofluorophosphate, MFP, Nombre Atomique 9, Sodium Fluoride, Sodium Monofluorophosphate, Stannous Fluoride.


Fluoride is a form of the chemical element fluorine. It is used as medicine.

Fluoride is added to public drinking water to prevent tooth decay. Children who do not drink fluorinated public water because their homes use water from a private well often take fluoride tablets to prevent tooth decay. Fluoride is added to toothpaste and mouthwashes so it can be applied directly to the teeth to prevent tooth decay.

Fluoride is also taken by mouth for treating weakened bones (osteoporosis) and for preventing bone loss in people with rheumatoid arthritis and Crohn's disease.

How does it work?

Fluoride protects teeth from the bacteria in plaque. It also promotes new bone formation. This is different than most medicines used for weak bones (osteoporosis), which fight osteoporosis by keeping bone from being broken down.


What causes tooth decay? See Answer

Uses & Effectiveness

Effective for...

  • Preventing tooth decay, when fluoride is added to drinking water or included in toothpastes, mouthwashes, and other dental products.

Possibly Effective for...

  • Treating osteoporosis (bone loss). Fluoride taken by mouth continuously or cyclically (three months on, one month off) might increase bone mineral density, which is an indicator of bone strength. Fluoride seems to work better for improving bone strength in older women when combined with hormone replacement therapy. However, it's not clear whether taking fluoride actually reduces the chance of weak bones breaking.

Insufficient Evidence to Rate Effectiveness for...

  • Preventing bone loss in people with rheumatoid arthritis.
  • Preventing bone loss in people with Crohn's disease (an intestinal disorder).
  • Other conditions.
More evidence is needed to rate the effectiveness of fluoride for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

Fluoride is safe for most people in the amounts added to public water supplies and used in toothpastes and mouthwashes, and applied by dentists. Low doses (up to 20 mg per day of elemental fluoride) of supplemental fluoride taken by mouth appear to be safe for most people. Higher doses are UNSAFE and can weaken bones and ligaments, and cause muscle weakness and nervous system problems. High doses of fluoride in children before their permanent teeth come through the gums can cause tooth discoloration.

Toothpaste and fluoride rinses should not be swallowed routinely, particularly by children. It's a good idea to make sure that children under six years of age use only a pea-sized amount of fluoride-containing toothpaste, just in case they swallow some.


Mouth Problems: TMJ, Canker Sores, Painful Gums and More See Slideshow

Special Precautions & Warnings

Pregnancy and breast-feeding: Fluoride seems to be safe during pregnancy and breast-feeding when taken in doses below the tolerable upper intake level (UL) of 10 mg per day of elemental fluoride and when applied directly to the teeth in toothpastes and mouthwashes. But higher doses are UNSAFE and can weaken bones and ligaments, and cause muscle weakness and nervous system problems.


The following doses have been studied in scientific research:


  • To prevent tooth decay (dental caries): in the US, fluoride is added to city water to a concentration of 0.7 to 1.2 parts per million (ppm). To prevent dental caries in areas where the fluoride level in drinking water is less than 0.3 ppm (such as in well water), children 6 months to 3 years should receive a fluoride supplement of 0.25 mg per day; children 3 to 6 years, 0.5 mg per day; and children 6 to 16 years, 1 mg per day. For children living in areas where the fluoride level is 0.3 to 0.6 ppm, children 3 to 6 years should receive 0.25 mg per day, and children 6 to 16 years, 0.5 mg per day. No supplement is needed in areas where the fluoride in drinking water exceeds 0.6 ppm.
  • For treating weak bones (osteoporosis): 15 to 20 mg per day of elemental fluoride.
The daily Adequate Intakes (AI) for elemental fluoride from all sources including drinking water are: infants birth through 6 months, 0.01 mg; babies age 7 through 12 months, 0.5 mg; children 1 through 3 years, 0.7 mg; 4 through 8 years, 1 mg; 9 through 13 years, 2 mg; 14 through 18 years, 3 mg; men 19 years and older, 4 mg; women 14 years and older, including those who are pregnant or breast feeding, 3 mg.

The daily upper intake levels (UL) for fluoride, the highest level at which no harmful effects are expected, are 0.7 mg for infants birth through 6 months; 0.9 mg for infants 7 through 12 months; 1.3 mg for children 1 through 3 years; 2.2 mg for children 4 through 8 years and 10 mg for children older than 8 years, adults, and pregnant and breast feeding women.

Sodium fluoride contains 45% elemental fluoride. Monofluorophosphate contains 19% elemental fluoride.

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Adachi JD, Bell MJ, Bensen WG, et al. Fluoride therapy in prevention of rheumatoid arthritis induced bone loss. J Rheumatol 1997;24:2308-13.. View abstract.

Alexandersen P, Riis BJ, Christiansen C, et al. Monofluorophosphate combined with hormone replacement therapy induces a synergistic effect on bone mass by dissociating bone formation and resorption in postmenopausal women: a randomized study. J Clin Endocrinol Metab 1999;84:3013-20.. View abstract.

American Dental Association. "ADA Statement on FDA Toothpaste Warning Labels" http://www.ada.org/prof/prac/issues/statements/fluoride.html (Accessed 18 November 2002).

Brown JP, Josse RG, et al. 2002 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada. CMAJ 2002;167:S1-S34.. View abstract.

Centers for Disease Control. National Center for Chronic Disease Prevention and Health Promotion. "Dietary Fluoride Supplement Schedule." http://www.cdc.gov/OralHealth/factsheets/fl-supplements.htm (Accessed 18 November 2002).

Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press, 1999. Available at: http://books.nap.edu/books/0309063507/html/index.html.

Guanabens N, Farrerons J, Perez-Edo L, et al. Cyclical etidronate versus sodium fluoride in established postmenopausal osteoporosis: a randomized 3 year trial. Bone 2000;27:123-8.. View abstract.

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Meunier PJ, Sebert JL, Reginster JY, et al. Fluoride salts are no better at preventing new vertebral fractures than calcium-vitamin D in postmenopausal osteoporosis: the FAVOStudy. Osteoporos Int 1998;8:4-12.. View abstract.

Phipps KR, Orwoll ES, Mason JD, Cauley JA. Community water fluoridation, bone mineral density, and fractures: prospective study of effects in older women. BMJ 2000;321:860-4.. View abstract.

Position of the American Dietetic Association: the impact of fluoride on health. J Am Diet Assoc 2001;101:126-32.. View abstract.

Reginster JY, Meurmans L, Zegels B, et al. The effect of sodium monofluorophosphate plus calcium on vertebral fracture rate in postmenopausal women with moderate osteoporosis. A randomized, controlled trial. Ann Intern Med 1998;129:1-8.. View abstract.

Reginster JY, Rovati LC, Setnikar I. Correct regimen of fluoride and calcium reduces the risk of vertebral fractures in postmenopausal osteoporosis [letter]. Osteoporos Int 2001;12:800.

Ringe JD, Rovati LC. Treatment of osteoporosis in men with fluoride alone or in combination with bisphosphonates. Calcif Tissue Int 2001;69:252-5.. View abstract.

Rubin CD, Pak CY, Adams-Huet B, et al. Sustained-release sodium fluoride in the treatment of the elderly with established osteoporosis. Arch Intern Med 2001;161:2325-33.. View abstract.

Spak CJ, Ekstrand J, Zylberstein D. Bioavailability of fluoride added by baby formula and milk. Caries Res 1982;16:249-56.

von Tirpitz C, Klaus J, Bruckel J, et al. Increase of bone mineral density with sodium fluoride in patients with Crohn's disease. Eur J Gastroenterol Hepatol 2000;12:19-24.. View abstract.