This strongly supports the potential use of vitamin B3 precursors as exercise mimetics to facilitate the increase in muscle mitochondrial mass of patients with mitochondrial myopathy, since exercise interventions remain the most compelling method to activate PGC-1α signalling and mitochondrial biogenesis [125–127], but may be out of reach for patients with severe exercise intolerance and other complications. This evidence concerns the gene PPARGC1A and Mitochondrial myopathy.