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Fluoride in drinking water has no effect on IQ or brain function, long-term study shows
(www.nbcnews.com)
this post was submitted on 14 Apr 2026
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Fluoride does harm brain development, but only if you get way too much of it. This happens in some places where the natural water already contains a lot of fluoride. You absolutely don't want to add even more fluoride there.
But most places, especially in the US, the fluoride level is far below that, so far below that we have to add fluoride to the water to get enough to maintain dental health. But it's still far below the level that causes harm.
The big issue is that the process to make ground water safe to drink removes the Sodium Flouride from it. We have to add it back in, unless you live in a town like mine where they decided to stop flouridating the water because they believe in conspiracy theories and Facebook science.
The levels you need to consume to cause harm are pretty substantial. You would have to be intentionally consuming a LOT of Sodium Flouride to cause issues. It's almost on the level of "how many bananas do you need to eat to get radiation poisoning".
That is dangerous misinformation. With an LD50 of 0.052 grams per kilogram of body weight, swallowing a teaspoon of sodium fluoride will kill most people (if they aren't induced to vomit or receive emergency medical attention). It's harmless in the dosage put in tap water, but if you have a tub of pure sodium fluoride it is similarly toxic to bleach or moth balls.
Meanwhile you physically can't eat enough bananas to get radiation poisoning. Bananas are less radioactive than human flesh, less radioactive than hotdogs, less radioactive than potatoes. You can swim in liquefied banana and be exposed to less radiation than walking outside on a cloudy day without sunscreen.
You physically can't drink enough (properly) fluoridated water to get fluoride poisoning.
Some back of the napkin math says a typical American (rounded to 200lbs) would need ~67 liters of water to get a lethal does of fluoride. Some lazy googling says that the absolute most your kidneys would handle is 20 liters in a 24hr period before they start failing. Literally, the amount water you can drink is more toxic than the amount of fluoride in it.
That's not what they said, though. What they said is that "you would have to be intentionally consuming a LOT of sodium fluoride to cause issues". Not fluorinated water, sodium fluoride. The actual salt that kills you if you eat a teaspoon of it.
That’ll be a risk if you have pure sodium fluoride sitting around. Fortunately “no one” does. (Yes, industrial toothpaste manufacturing workers might have an opportunity to be exposed to such a thing).
Typical toothpaste is 1000-1100 ppm of sodium fluoride. “Prescription strength” is about 5000 ppm. So to hit your target LD50 you need to eat around 10 g of toothpaste per kg. Assuming on the extremely small end (40 kg bodyweight): if I did my math right, that’s about 400 g of prescription strength toothpaste, or more than two (170 g) tubes.
Normal toothpaste (1100 ppm) for a normal person (80 kg female average), you need to eat more than 22 tubes of toothpaste to kill half the people involved.
Thats just stupid, there’s zero risk of any of that happening.
Look, I'm not saying the average consumer will ever run into this risk, I'm saying that you shouldn't go around saying H301 acutely toxic chemicals are as safe to ingest as bananas. You're not the president of the United States.
That's not what they were saying. They were saying the levels in drinking water are so low that it's comparable to radiation levels in bananas.
As in, you'd need to consume so much for it to be lethal that you'd have to be intentionally doing it to cause harm to yourself.
I believe it is what they meant to say, but it is simply not what they said.
The bolded sentence is unambiguous. It uses no prepositions, no context-dependent phrases, no complex punctuation. It is a simple sentence ending in a full stop. How can you deny this is what they said?
And a teaspoon is 5 ml. Flouridated water is, on average, 0.7 mcg/L. Therefore, you would have to drink over 17,000 liters of water for the flouride to kill you.
That's cool, but kind of irrelevant to their remark that sodium fluoride is safe.
It is safe. The dose makes the poison.
Shit, even pure oxygen can kill you.
I wouldn't call a chemical that kills you if you eat a teaspoon of it "safe". It literally has a H301 "acutely toxic chemical" rating.
sigh
It's safe in the levels added to drinking water.
Absolutely no one is saying pure sodium fluoride is safe.
- The person I first replied to
Why are you getting downvoted for providing relevant facts? Sometimes this place is as reactionary as 8chan
Critically judging authorial intent is a 6th grade reading level, and 54% of USAmerican adults have a 5th grade reading level or below. I could have written it more for my audience, the sort of person that needs to hear that pure sodium fluoride is unsafe to ingest.
It also begins to have a purely cosmetic but noticeable impact on your teeth long before the detrimental health effects kick in.
Bro, I eat half a tube of toothpaste a day for the health benefits. Have been doing that since I was 8.
Edit: /s for smooth brains
I wonder why we don't handle it like any other vitamin? Where's my multivitamin tap water?!
I filter my water, so the fluoride goes to waste sadly. Wonder if it comes in a small dose pill.
It does. But I don't know if there's a reason we fluoridate water and not something else, like iodine in salt and all the stuff they put in enriched flour.
Perhaps has to do with the medium and the tendency of things to decay away. Maybe fluoride is stable in water, but something like Vitamin D would break down. Sunlight for example breaks down some things like that. I imagine water is probably a difficult medium to survive in for a lot of things.