Described herein are compositions suitable for the treatment of pathological conditions distinguished by insufficient or reduced mitochondrial function. The compositions comprise, as principal active ingredients, the amino acids leucine, isoleucine and valine. Preferably envisaged, as further active ingredients, are the amino acids threonine and lysine, and possibly histidine, phenylalanine, methionine, tryptophan, as well as tyrosine and cyst(e)ine.
