In chemistry, a molecular formula expresses the types and numbers of atoms present in a molecule or chemical, whereby subscripts are used to indicate the number of atoms present in the chemical entity.  The molecular formula for water, H20, for instance, means that there are two hydrogen atoms and one oxygen atom in one molecule of water.
● Human molecular formula
1. Daintith, John. (2005). Oxford Dictionary of Chemistry. Oxford University Press.
● Chemical formula – Wikipedia.