He was born as Hippolyte Mège, the son of a primary school teacher, but later added his mother's surname to his own. In 1838, Mège obtained a job in the central pharmacy of the Hôtel-Dieu hospital in Paris and started to publish original contributions in applied chemistry.
Mège focussed on fat processing in the 1860's, which culminated in 1869 in a patent for margarine. His invention involved mixing processed beef tallow with skimmed milk, and resulted in a cheap but qualitatively good substitute for butter 'for the working class and incidentally the Navy'. Mège received a prize from the French government, formally led by Emperor Louis Napoleon III. In 1871, Mège sold his invention to the Dutch firm Jurgens, one of the pillars of Unilever.