Fluoride in drinking water and toothpaste is absolutely essential, unless, of course, it's making you dumb and sick. What does science say?
Protein causes kidney damage. Squats are bad for the knees. Creatine has killed a few people. None of those statements is true, but many people believe them.
Why? Probably due to a phenomenon known as belief perseverance: the tendency to maintain a belief even after the original evidence supporting it is debunked. In short, it's really hard to un-believe the first thing you believed to be true about a subject.
Well, here's another statement for you to mentally test out: "Fluoride is good for you and prevents tooth decay."
What's your brain doing right now? Is it saying, "Of course, everyone knows that!" Or is it saying, in its best Dwight Schrute impersonation, "False! It's a neurotoxin and doesn't help much with dental health anyway."
Both responses might be examples of belief perseverance. You either believe what you've been told since childhood, or you believe conspiracy theorists on social media. The pro-fluoride side of the debate thinks the other side is nuts. The anti-fluoride side thinks the other side is ignorant.
What's really going on? What do studies show?
The fluoride facts
Fluoride is a naturally occurring mineral found in rocks, soil, and water. Even non-fluoridated water can contain fluoride. Most foods contain trace levels. Things like teas, seafood with edible bones or shells, and raisins can contain higher (but still tiny) amounts.
Fluoride isn't considered an essential nutrient for basic physiological functions like other minerals. And fluoride deficiency isn't recognized as a clinical condition because the body doesn't require it for essential metabolic processes. If a person managed to avoid fluoride completely, they might be at risk of increased tooth decay, but that's about it.
Most studies do show that fluoride reduces tooth decay by strengthening enamel and inhibiting bacterial acid damage. A 2025 review on water fluoridation indicates that fluoride in drinking water at 0.7 ppm (parts per million) reduces the incidence of tooth decay in children by around 25%.
About 73% of the U.S. population on public water systems receives fluoridated water at the recommended 0.7 ppm. Most toothpaste brands add fluoride, typically at 1,000 to 1,500 ppm.
Now, if you ask the experts if fluoride is toxic, the typical answer is no, it's not toxic at the low levels found in U.S. drinking water or toothpaste. But read between the lines. That rote answer means fluoride is toxic at high levels.
Chronic exposure to water above 1.5 ppm over the years leads to dental fluorosis (enamel discoloration) in children under 8, while levels above 4 ppm (the EPA's maximum limit) can cause skeletal fluorosis, increasing bone fragility. But, as the pro-fluoride brigade says, you have to be purposefully swallowing a lot of toothpaste to reach those levels.
So what's the controversy?
A 2025 National Toxicology Program review and other studies suggest a potential link between high fluoride exposure (>1.5 ppm in water) and lower IQ in children. A 2016 Mexican study found that higher prenatal fluoride exposure correlated with lower IQ scores in kids, though the fluoride levels tested (often >2 ppm) were higher than typical U.S. water levels.
Critics argue these studies often fail to account for confounding factors (nutrition, socio-economic status) and use fluoride levels far exceeding those in fluoridated water.
Alternative health experts claim fluoride causes pineal gland calcification, thyroid dysfunction, or nutrient absorption issues. So far, those claims lack robust peer-reviewed evidence. A 2025 Cochrane review suggests water fluoridation reduces tooth decay by only a "tiny amount" (about 0.25 fewer decayed teeth per person), leading some to question its necessity given widespread access to fluoride toothpaste.
The worry of the anti-fluoride folks? Total fluoride exposure. Even a SCHER report from 2010 calls for better biomarkers and standardized methods to assess total fluoride exposure from all sources (water, food, toothpaste) to clarify risks.
Should I be worried?
As long as you're not a child who's eating toothpaste, you probably don't have to worry too much. Probably. Future studies may tell us a different story.
However, it's not exactly comforting to know you're ingesting a substance that is indeed toxic and maybe IQ-lowering, even if it's in small amounts. And problems could conceivably arise if you're drinking several liters of fluoridated water daily, using a high-fluoride toothpaste, adding a mouthwash with fluoride, and drinking a lot of black or green tea to wash down your sardines.
Given that it doesn't take much fluoride to lessen tooth decay and you're likely already getting it from water, switching to a fluoride-free toothpaste is an easy way to bring down your levels, just in case.
If fluoride really worries you, take curcumin. A 2023 study investigated curcumin's neuroprotective effects against fluoride-induced brain damage in rat models, focusing on its ability to mitigate cellular and biochemical alterations.
When rats were purposefully given way too much fluoride, they experienced oxidative stress, leading to disrupted cellular homeostasis. This caused lipid peroxidation, mitochondrial dysfunction, and neuronal apoptosis (cell death). It also altered neurotransmitter levels and increased inflammatory markers like TNF-α and IL-6, impairing cognitive functions like learning and memory.
However, the fluoridated rats given curcumin experienced reduced oxidative stress, mitigated neuroinflammation, and neuroprotection. Curcumin even restored levels of key brain enzymes and neurotransmitters disrupted by fluoride.
This study aligns with other new research on curcumin's neuroprotection, like its effects on Alzheimer's (reducing amyloid plaques) and SARS-CoV-2-related neuronal inflammation.
Given all of curcumin's other benefits, it's a smart idea to take it anyway, even if you're not too worried about fluoride. Just be sure to use the micellar form, which is 95 times more bioavailable than curcumin with piperine. Micellar Curcumin âž” Buy at Biotest contains 400 mg of this highly absorbable form.
