Mikel Vsauce (Vsauce youtube channel) said in his video that it takes about 5 years for the body replace all of its atoms, while in asapscience youtube channel they are claiming that it takes 10 years. I am confused and I can't find anywhere the precise time it takes.

Mikel's video (minute 1:14) AsapScience video (minute 1:07)

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    $\begingroup$ It would have been nice if there were some references/studies for that claim. I'm not sure for example if DNA in neurones in CNS (i.e. brain) get replaced unless its through DNA repair mechanism but still, that claim should be viewed with some amount of scepticism until a study is put forward and the assumptions are clarified! $\endgroup$ – Behzad Rowshanravan Aug 14 '14 at 19:06
  • $\begingroup$ quora.com/… $\endgroup$ – Daniel Aug 14 '14 at 21:21
  • $\begingroup$ I also imagine atoms in the bone mineral that sets in the actual matrix doesn't change too often. $\endgroup$ – Atl LED Aug 15 '14 at 3:51
  • $\begingroup$ I expect this to have a mathematical model resembling a half life. Bone turnover is significant. Bone remodeling is part of the normal mechanism for responding to physical activity. Bone loss in space is also significant doe to this effect. cjasn.asnjournals.org/content/3/Supplement_3/S131.full $\endgroup$ – 12345678910111213 Aug 15 '14 at 7:35
  • $\begingroup$ I don't think Iron would be totally replaced because we can't excrete it well. The iron in our red blood cells is very efficiently recycled by macrophages, and excess iron is stored in hepatocytes. If you really have too much iron it will accumulate as hemosiderin in hepatocytes, which is almost irreversible. The best way to treat iron overload is through regular blood draws, which is a non-natural way to remove iron, I don't know if men have a natural way to remove excess iron, so if the atoms can't leave, they can't be replaced. $\endgroup$ – user137 Aug 15 '14 at 18:00

Not all the atoms in the human body are replaced.

Carbon atoms in tooth enamel are not replaced after the enamel is laid down during tooth development. This was demonstrated in the 2005 Nature article "Forensics: Age written in teeth by nuclear tests", where the researchers showed that the amount of carbon-14 in tooth enamel can be used to accurately determine date of birth.


No. Some structures in the body are ever present from birth to death. The first things which come to mind are nerves, the eyes, the auditory hairs in the ears and the list goes on.....

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    $\begingroup$ could you please reference this! I tend to agree with you but over time replacement at molecular level is not inconceivable for any structure in the human body hence it would be nice to get some solid references! $\endgroup$ – Behzad Rowshanravan Aug 15 '14 at 16:36
  • $\begingroup$ Sure but I have not ate today so I am hungry it will be a while $\endgroup$ – user1357 Aug 15 '14 at 16:40
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    $\begingroup$ I don't know about this. While it's true that cells in many parts of our body don't divide and have to last our entire lives, the atoms in those cells might be turned over. While the same neuron may last for 80 years, it will have to make some repairs to the membranes, DNA, proteins, etc. Whether or not this happens quickly enough to get total replacement within a human lifetime I can't say. $\endgroup$ – user137 Aug 15 '14 at 17:56
  • $\begingroup$ @Bez i added references...if you would like citations that is possible too. $\endgroup$ – user1357 Aug 15 '14 at 23:17
  • $\begingroup$ @user137 no it does not atoms are extremely tiny there are just too many of them. $\endgroup$ – user1357 Aug 15 '14 at 23:18

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