Bone fluoride and skeletal fluorosis: a safety check

14 November 2014 – last modified 2022

If I was an arthritic individual, I would be eliminating every possible source of fluoride exposure that I could think of.

Dr Phyllis Mullenix, Toxicologist

Fluoride is a nonbiodegradable, cumulative poison which accumulates predominantly in bone and causes skeletal fluorosis. The 2006 US National Research Council report Fluoride in Drinking Water: A Scientific Review of EPA’s Standards, though far from perfect, is the most comprehensive review of fluoride toxicity conducted so far. In the chapter on musculoskeletal effects it says “A previous NRC report (NRC 1977) stated that a retention of 2 mg of fluoride per day (corresponding approximately to a daily intake of 4-5 mg) ‘would mean that an average individual would experience skeletal fluorosis after 40 yr, based on an accumulation of 10,000 ppm fluoride in bone ash.'” (NRC 2006, 143) I thought I’d do a calculation to check that claim of 10,000 ppm accumulated fluoride in bone ash, which is enough to cause the crippling, third stage of skeletal fluorosis in many people.

A retention of 2 mg of fluoride per day for 40 years gives

0.002(40)(365.25) = 29.22 grams

, which happens to be several times higher than what is required to kill an average adult if taken in a single dose. Bone ash weight is a measure of bone mineral content, and according to the US Centers for Disease Control and Prevention the average total age-adjusted body bone mineral content for males 20 years and over is 2720.04 g, measured by dual energy x-ray absorptiometry (DXA) (Looker et al 2013, 9). That gives a fluoride concentration of

29.22(1,000,000)/2720.04 = 10,742.5 ppm or 11,000 ppm to 2 significant figures.

The corresponding calculation for women is

29.22(1,000,000)/2108.32 = 13,859.4 ppm or 14,000 ppm.

On the face of it, the 1977 NRC calculation was an underestimate. However, the pathological increase in bone mass which can accompany skeletal fluorosis has not been taken into account here. It could be also be argued that measurement by DXA is not an adequate substitute for measurement of bone ash weight, though, so let’s look at it from a different angle. The average dry, defatted skeleton weight for young adult males has been estimated at 4.0 kg (Malina 2005, 291). Throwing the white supremacist fluoridationists a bone, the average percentage total skeleton ash weight for white adult males aged 30 to 85 years has been estimated as 66.4% (Trotter and Hixon 1974, 13-14).

percentage ash weight = (weight of ash)(100)/weight of dry, fat-free bone

so fluoride concentration in bone ash = 29.22(1,000,000)/(4.0)(1000)(0.664) = 11,001.5 (i.e. 11,000) ppm

Again, the corresponding figure for women will be considerably higher.

The data upon which these calculations are based are not perfect, a daily fluoride retention of 2 mg is probably somewhat higher than average, and around 99% of retained fluoride is found in bone, not 100%. Nevertheless, this preliminary investigation strongly suggests that being force fluoridated for a lifetime is very far from safe. “On the basis of data on fluoride in the iliac crest or pelvis, fluoride concentrations of 4,300 to 9,200 mg/kg in bone ash have been reported in cases of stage II fluorosis, and concentrations of 4,200 to 12,700 mg/kg in bone ash have been reported in cases of stage III fluorosis. The overall ranges for other bones are similar.” (NRC 2006, 143) From what I’ve read, some common early symptoms or signs of skeletal fluorosis are gastrointestinal issues (Susheela et al 2014, 576), neck stiffness, and knee osteoarthritis (Savas et al 2001).


  1. Looker AC, Borrud LG, Hughes JP, Sherman M (2013). Total body bone area, bone mineral content, and bone mineral density for individuals aged 8 years and over: United States, 1999-2006. National Center for Health Statistics. Vital and Health Statistics 11(253): 1-78.
  2. Malina RM (2005). Variation in body composition associated with sex and ethnicity. In: Heymsfield SB, Lohman TG, Wang Z, Going SB, editors. Human body composition. 2nd ed. Champaign, IL: Human Kinetics. p. 271–298.
  3. NRC (National Research Council) (2006). Fluoride in drinking water: a scientific review of EPA’s standards. Washington DC (USA): National Academies Press 530 p.
  4. Savas S, Cetin M, Akdogan M, Heybeli N (2001). Endemic fluorosis in Turkish patients: relationship with knee osteoarthritis. Rheumatology International 21(1): 30-35.
  5. Susheela AK, Mondal NK, Tripathi N, Gupta R (2014). Early diagnosis and complete recovery from fluorosis through practice of interventions. Journal of the Association of Physicians of India 62: 572-579.
  6. Trotter M, Hixon BB (1974). Sequential changes in weight, density, and percentage ash weight of human skeletons from an early fetal period through old age. The Anatomical Record 179(1): 1-18.

10 comments on “Bone fluoride and skeletal fluorosis: a safety check

  1. rocketknight1

    Interesting analysis, but don’t the effects of fluoride release from bone need to be considered? Bone is continuously being remodelled, so as the concentration of fluoride in bone increases, we should presumably expect the rate of fluoride release to also increase.

    I have no idea about the relevant reaction rates, but it might be the case that if your daily fluoride intake is constant and low/moderate, then fluoride release might asymptotically approach the rate of fluoride retention, and your bones would eventually settle to a relatively stable fluoride concentration.

    I could be wrong, though, you’d need a proper model for fluoride release rates, or maybe just to look at the fluoride concentrations in the bones of elderly people who have been drinking fluoridated water for most/all of their lives to see if that matches your calculations.

    I’d be interested if you knew of any studies that had been done in that area.

    1. Forced Fluoridation Freedom Fighters Post author

      Sorry, I didn’t realise your comment had been caught in the spam filter, or whatever it’s called. You make a good point, and it’s something I’ve thought about myself, but based on what I’ve read so far fluoride release from bone isn’t going to make a huge difference, though it may be significant. The half-life of fluoride release from bone has been estimated at 20 years, so it’s very slow. From memory, the maximum fluoride concentration in bone ash is 37,700 ppm, so bone doesn’t need to be anywhere near saturated with fluoride for someone to have the third stage of skeletal fluorosis. Also, bear in mind that I used 40 or 50% as the rate of fluoride retention, but it’s actually much higher than that in children and adolescents, and the elderly are more likely to have impaired kidney function than younger people, which reduces the rate of fluoride clearance. Apparently it was recommended in an Australian NHMRC review that fluoride concentrations in people who have died be studied, but that has been ignored by the authorities. I am not aware of any similar studies, but I’m going to look into it in more detail.

      p 75 “Fluoride is rapidly absorbed from the gastrointestinal tract, with a half-life of about 30 minutes. After a single dose, plasma concentrations rise to a peak and then fall as the fluoride is cleared by the renal system and bone, decreasing back to (short-term) baseline with a half-life of several hours. Fluoride concentrations in plasma are not homeostatically controlled (Whitford 1996). Chronic dosing leads to accumulation in bone and plasma (although it might not always be detectable in plasma.) Subsequent decreases in exposure cause fluoride to move back out of bone into body fluids, becoming subject to the same kinetics as newly absorbed fluoride. A study of Swiss aluminum workers found that fluoride bone concentrations decreased by 50% after 20 years. The average bone ash concentration in the workers was about 6,400 mg/kg at the end of exposure, estimated via regression (Baud et al. 1978). The bone concentration found in these workers is similar to that found in long-term consumers of drinking water containing fluoride in the range of 2-4 mg/L (discussed later in this chapter). Twenty years might not represent a true half-life. Recent pharmacokinetic models (see below) are nonlinear, suggesting that elimination rates might be concentration dependent.”

      2006 US National Research Council report Fluoride in Drinking Water: A Scientific Review of EPA’s Standards

      Edit: The 20 year half-life mentioned in the quote above refers to a situation in which fluoride exposure was dramatically reduced from previous long-term levels. Studies show that when exposure is more or less constant, fluoride continues to steadily accumulate in the body throughout life.

    2. James Farris

      Ppm= 1 mg/L

      0.7 ppm (The current US Standard) = 0.7 mg / L

      Intake of 4.5 mg / day

      4.5 mg/ day * L / 0.7 mg = 6.42 L / day or 1.7 gallons/ day (more than three times what recommended water intake is)
      If drinking more than three times the recommended water intake results in the condition in 40 years, then drinking the recommended water intake would result in the condition in 120 years.

      The average person drinks quite a bit less than the recommended water intake, so the average person would not have to worry about this condition for greater than 120 years.

      1. Forced Fluoridation Freedom Fighters Post author

        James, I’ve already told you elsewhere why your analysis is garbage, which you could have figured out for yourself if you had half a brain. You forced-fluorifuckation freaks really are the world’s stupidest arseholes.

  2. Ian Joyner

    “Putting industrial pollution and its pushers in their place” this is just hysterical nonsense

  3. Pingback: Is fluoride in water naturally? – Welcome to Fluoride Free Sudbury

Comments are closed.