The composition of the microbiome - the collection of micro-organisms that inhabit our skin, which represents most of the genes present in the human body - may be one of the factors influencing the skin's ageing process. This is according to a joint study conducted by the Microbiome Innovation Centre at the University of California, San Diego, and L'Oréal's Research and Innovation Department. The results of this research were published in the January issue of the journal Frontiers in Aging .