Elemental Composition of the
Human Body

Ed Uthman, MD

Diplomate, American Board of Pathology

Posted St. Valentine's Day, 2000

The table below gives the amount of each chemical element found in the human body, from most to least abundant. For each element, there is the amount in mass units in an averge (70-kilogram) person, the volume of the element, and the length of the side of a cube that would contain that amount of the pure element. Volumes of solid and liquid elements are based on density at or near room temperature (where available). For the gaseous elements (oxygen, hydrogen, nitrogen, chlorine, and fluorine), I chose to use the density of each in the liquid state at the respective boiling point.

Raw data from which this table was made are from Emsley, John, The Elements, 3rd ed., Clarendon Press, Oxford, 1998. This is a great trove of information, which I highly recommend for anyone wishing to learn more about the elements.

Element Mass of element
in a 70-kg person
Volume of
purified element
Element would
comprise a cube
this long
on a side:
oxygen 43 kg 37 L 33.5 cm
carbon 16 kg 7.08 L 19.2 cm
hydrogen 7 kg 98.6 L 46.2 cm
nitrogen 1.8 kg 2.05 L 12.7 cm
calcium 1.0 kg 645 mL 8.64 cm
phosphorus 780 g 429 mL 7.54 cm
potassium 140 g 162 mL 5.46 cm
sulfur 140 g 67.6 mL 4.07 cm
sodium 100 g 103 mL 4.69 cm
chlorine 95 g 63 mL 3.98 cm
magnesium 19 g 10.9 mL 2.22 cm
iron 4.2 g 0.53 mL 8.1 mm
fluorine 2.6 g 1.72 mL 1.20 cm
zinc 2.3 g 0.32 mL 6.9 mm
silicon 1.0 g 0.43 mL 7.5 mm
rubidium 0.68 g 0.44 mL 7.6 mm
strontium 0.32 g 0.13 mL 5.0 mm
bromine 0.26 g 64.2 µL 4.0 mm
lead 0.12 g 10.6 µL 2.2 mm
copper 72 mg 8.04 µL 2.0 mm
aluminum 60 mg 22 µL 2.8 mm
cadmium 50 mg 5.78 µL 1.8 mm
cerium 40 mg 4.85 µL 1.7 mm
barium 22 mg 6.12 µL 1.8 mm
iodine 20 mg 4.06 µL 1.6 mm
tin 20 mg 3.48 µL 1.5 mm
titanium 20 mg 4.41 µL 1.6 mm
boron 18 mg 7.69 µL 2.0 mm
nickel 15 mg 1.69 µL 1.2 mm
selenium 15 mg 3.13 µL 1.5 mm
chromium 14 mg 1.95 µL 1.3 mm
manganese 12 mg 1.61 µL 1.2 mm
arsenic 7 mg 1.21 µL 1.1 mm
lithium 7 mg 13.1 µL 2.4 mm
cesium 6 mg 3.2 µL 1.5 mm
mercury 6 mg 0.44 µL 0.8 mm
germanium 5 mg 0.94 µL 1.0 mm
molybdenum 5 mg 0.49 µL 0.8 mm
cobalt 3 mg 0.34 µL 0.7 mm
antimony 2 mg 0.30 µL 0.7 mm
silver 2 mg 0.19 µL 0.6 mm
niobium 1.5 mg 0.18 µL 0.6 mm
zirconium 1 mg 0.15 µL 0.54 mm
lanthanium 0.8 mg 0.13 µL 0.51 mm
gallium 0.7 mg 0.12 µL 0.49 mm
tellurium 0.7 mg 0.11 µL 0.48 mm
yttrium 0.6 mg 0.13 µL 0.51 mm
bismuth 0.5 mg 51 nL 0.37 mm
thallium 0.5 mg 42 nL 0.35 mm
indium 0.4 mg 55 nL 0.38 mm
gold 0.2 mg 10 nL 0.22 mm
scandium 0.2 mg 67 nL 0.41 mm
tantalum 0.2 mg 12 nL 0.23 mm
vanadium 0.11 mg 18 nL 0.26 mm
thorium 0.1 mg 8.5 nL 0.20 mm
uranium 0.1 mg 5.3 nL 0.17 mm
samarium 50 µg 6.7 nL 0.19 mm
beryllium 36 µg 20 nL 0.27 mm
tungsten 20 µg 1.0 nL 0.10 mm

Notes

Oxygen is the most abundant element in the earth's crust and in the body. The body's 43 kilograms of oxygen is found mostly as a component of water, which makes up 70% of total body weight. Oxygen is also an integral component of all proteins, nucleic acids (DNA and RNA), carbohydrates, and fats.

Rubidium is the most abundant element in the body (0.68 g) that has no known biological role (silicon, which is slightly more abundant, may or may not have a metabolic function).

Vanadium is the body's least abundant element (0.11 mg) that has a known biologic role, followed by cobalt (3 mg), the latter being a constituent of vitamin B12.

The last of the body's elements to be discovered was fluorine, by Moissan in 1886.

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