In a study involving a rotenone-induced cellular model of Parkinson's disease (PD), 4-week pre-treatment with a combination of R-alpha-lipoic acid (LA) and acetyl-L-carnitine (ALC) was found to protect SK-N-MC human neuroblastoma cells against rotenone-induced mitochondrial dysfunction, oxidative damage, and accumulation of alpha-synuclein and ubiquitin, and to increase mitochondrial biogenesis and decrease production of reactive oxygen species (ROS). Moreover, when the 2 antioxidant substances were given in combination, LA worked at a 100-fold lower concentration and ALC worked at a 1000-fold lower concentration, as compared to when the substances were given individually. Given the fact that mitochondrial dysfunction and oxidative damage are significantly involved in the pathogenesis of Parkinson's disease, these results are promising. The authors conclude, "This study provides important evidence that combining mitochondrial antioxidant/nutrients at optimal doses might be an effective and safe prevention strategy for PD."