human elemental composition

Bill Purves purves at
Wed Aug 30 16:29:33 EST 1995

In article <421pbs$no2 at>,
Anthony Duncan <aduncan at> wrote:
>Can anyone indicate what is the elemental composition of an average human  
>being.  I assume the principal elements are Oxygen, Carbon, Nitrogen and  
>Hydrogen and traces of mineral salt elements. But I do not know in what  
>percents.  I assume the highest would be O since we are made mainly of  
>water (H2O).  

Good guess about oxygen.

Here are some approximate numbers, as percent of human body mass:

H 9.5	C 18.5	N 3.3	O 65.0	Na 0.2	Mg 0.1	P 1.0	S 0.3
Cl 0.2	K 0.4	Ca 1.5

Other elements are present in much lower concentration (as may be
inferred from the sum of the numbers above ;-)


William K. Purves
Department of Biology
Harvey Mudd College
Claremont, CA 91711
Bill_Purves at

More information about the Bioforum mailing list