Recently, new evidence trying to connect insomnia with mitochondrial dysfunction in a small group of post-menopausal female patients (age 55–70 years) suffering by either objective or paradoxical insomnia, shows that both forms of insomnia elicit a stress response involving myokines’ production (FGF21, GDF15 and HN, molecules that expressed in response to mitochondrial stresses) [56]. The gene discussed is FGF21; the disease is insomnia.