What elements are present in the human body?

	Vocabulary
	element

Living cells contain anywhere from 65 to 90% water by weight, so it's no surprise that most of the body's mass is oxygen. Carbon, the basic building block of organic compounds, takes second place. Together, the top six body elements - oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus - account for about 99% of the body's mass.

Elemental composition of living cells. Source: H. A. Harper, V. W. Rodwell, P. A. Mayes, Review of Physiological Chemistry, 16th ed., Lange Medical Publications, Los Altos, California 1977.

Element Composition by Weight (%)

O 65

C 18

H 10

N 3

Ca 1.5

P 1.0

K 0.35

S 0.25

Na 0.15

Mg 0.05

Cu,Zn,Se,Mo,F,Cl,I,Mn,Co,Fe 0.70

Li,Sr,Al,Si,Pb,V,As,Br traces

But this is like describing a slice of Black Forest chocolate cake as "mostly carbon, hydrogen, and oxygen". A list of ingredients completely misses what's essential and interesting about the cake. As Hermann Muller put it, "To say that a man is made up of certain chemical elements is a satisfactory description only for those who intend to use him as a fertilizer."

Author: Fred Senese senese@antoine.frostburg.edu

General Chemistry Online! What elements are present in the human body?