Symptoms of too much fluoride

Fluoride is a mineral that is beneficial for dental health in low to moderate amounts. However, long-term ingestion of excess fluoride during childhood can lead to a condition called fluorosis. There are two types of fluorosis – dental fluorosis and skeletal fluorosis.

Systemic fluoride toxicity usually arises when you ingest around 5 mg of Fluoride per kg of bodyweight, which translates to 375 mg of Fluoride for a person weighing 165 pounds (75 kgs). [For perspective, you brush your teeth with about 1mg of Fluoride]

Considering the huge amount of Fluoride required for toxicity to occur, an excess amount can only ingested accidentally. This may arise from:

  • Accidents that cause excessively high water fluoridation
  • Giving children fluoride supplements inappropriately, or
  • Unintentionally ingesting fluoride products designed for topical use in the dentist’s office.

Below are the side effects of too much fluoride and the associated symptoms:

Dental fluorosis

Dental fluorosis occurs when children consume high levels of fluoride during the years when teeth are forming, which can result in white streaks or spots on the teeth. In more severe cases, the teeth may appear brown or black and may become pitted or damaged. It’s important to note that the effects of too much fluoride are typically not visible until after several years of exposure.

Severe enamel fluorosis is rare, and recommended levels of community water fluoridation do not lead to severe dental fluorosis. That said, about 22.8% of people aged 6-49 have dental fluorosis, the vast majority of which comprise the mild form of fluorosis, with adolescents being the most affected.

Dental fluorosis is primarily a cosmetic concern and does not typically affect the function of the teeth.

Ingesting too much fluoride can cause symptoms such as:

  • Nausea,
  • Vomiting,
  • Diarrhea,
  • Periostitis,
  • Abdominal pain, and even
  • Death, but this is rare.

It’s also worth noting that excess fluoride intakes during early development might be associated with lower IQ and cognitive impairments in children, though this evidence is controversial.

Skeletal fluorosis

In the event of chronic excess intake of fluoride, the individual may be at risk of developing skeletal fluorosis, which is characterized by the weakening of bones, resulting in:

  • joint pain or stiffness
  • osteoporosis – bones become denser and more brittle
  • muscle wasting
  • neurological defects
  • increased risk of fractures

Skeletal fluorosis is more commonly seen in areas with high levels of naturally occurring fluoride in the drinking water.

Children under one-year-old tend to incorporate nearly 90% of the fluoride ingested into their bone, and this gradually decreases to 50% by the age of 15 years.


Does excess fluoride cause osteosarcoma?

There is no conclusive evidence to support the claim that excess fluoride causes osteosarcoma, a type of bone cancer. Several studies have investigated the relationship between fluoride exposure and osteosarcoma, but the results have been mixed and inconclusive.

Some studies have suggested a possible link between high fluoride exposure and an increased risk of osteosarcoma, but these findings have been criticized for their methodological limitations and the potential for confounding factors. Other studies have found no association between fluoride exposure and osteosarcoma.

The American Cancer Society notes that there is currently no clear evidence that fluoride causes cancer in humans, including osteosarcoma. However, they also note that more research is needed to better understand the potential risks associated with high fluoride exposure.

It is important to note that the benefits of fluoride in preventing tooth decay are well-established, and the American Dental Association continues to recommend the use of fluoridated toothpaste for maintaining oral health. The key is to use fluoride products as directed and to avoid excessive exposure to fluoride.

Does excess fluoride cause any neurological effects?

There is some evidence to suggest that excess fluoride exposure may have neurological effects, particularly in children. One potential effect is a reduction in IQ, although the evidence is somewhat mixed on this point. Some studies have found a correlation between high fluoride exposure and lower IQ scores, while others have not.

Other potential neurological effects of excess fluoride include:

  • Altered behavior
  • Impaired motor function, and
  • Changes in brain chemistry.

These effects are generally seen at high levels of fluoride exposure, such as those seen in areas with high levels of naturally occurring fluoride in the drinking water.

Generally, most people in the United States are exposed to fluoride at levels that are considered safe and are unlikely to cause any adverse effects. The main concern is for people who are exposed to very high levels of fluoride, either through drinking water, industrial exposure, or other sources.

Does excess fluoride affect human reproduction?

There is some evidence to suggest that excessive fluoride intake may have an effect on human reproduction.

Some studies have linked high levels of fluoride exposure to decreased fertility in both men and women, as well as increased rates of stillbirths and infant mortality. Other studies have suggested that excessive fluoride intake may be associated with hormonal imbalances that can affect reproductive function.

However, more research is needed in this area to fully understand the potential effects of fluoride on human reproduction.

It is important to note that the levels of fluoride typically found in community water supplies and in most toothpaste products are generally considered safe and do not pose a risk to reproductive health.

Treatment options for dental fluorosis  

Dental fluorosis can cause discomfort and anxiety for many people depending on the symptoms experienced. Fortunately, there are several treatment options available that your dentist may recommend, including:

  • Professional tooth whitening
  • Homemade whitening remedies or commercial products
  • Tooth bonding
  • Dental veneers
  • Dental crowns

How to prevent symptoms of excess fluoride

While fluorosis is a cosmetic issue, it is also an indicator that the body has been exposed to high levels of fluoride. Therefore, it’s important to monitor fluoride intake to avoid potential health problems.

  • To avoid excessive fluoride intake, you should use the right amount of fluoride toothpaste for your age, and avoid swallowing.
  • You should also avoid drinking water that has a high concentration of fluoride and be aware of other sources of fluoride in the diet, such as tea, seafood, and processed foods that may have been prepared with fluoridated water.

Finally, individuals with kidney disease or other health conditions that affect fluoride metabolism should consult with their doctor to determine appropriate fluoride intake levels.


  • Editorial team

    A team comprising oral health care professionals, researchers, and professional Writers, striving to impart you with the knowledge to improve your oral health, and that of your loved ones. 

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