Pharmaceutical compositions acting on the metabolism which contain as active derivatives of the 4-hydroxy-3,5-di-akylphenyl-propionic acid corresponding to the formula I and II ##EQU1## wherein R.sub.1 and R.sub.2 which may be identical or different, each stands for an alkylradical having 1 to 8 carbon atoms, R.sub.3 stands for an alkylene radical having 2 to 12 carbon atoms, X stands for hydroxy, alkoxy having 1 to 18 carbon atoms, phenalkoxy having 1 to 4 alkyl carbon atoms, cycloalkoxy having...