The invention relates to the stimulation of the synthesis and of the activity of an isoform of lysyl oxidase, and more particularly of the LOXL (lysyl oxidase-like) isoform. The Invention relates notably to a method of identifying an active principle which stimulates the formation of elastic fibers. The aim of the invention is mainly to provide such a method of identification so as to provide compositions which enable stimulating the formation of elastic fibers.