Hydroxytyrosol or olive juice containing hydroxytyrosol in combination with at least one of the compounds selected from the group consisting of: creatine, coenzyme Q10, resveratrol, caffeine, carnitine, B vitamins (B1, B2, B3, B5, B6, and/or B12) and ginseng (preferably: root) extract can be used to maintain or increase mitochondrial biogenesis in cardiac muscle, skeletal muscles, and liver tissue.