Scheme of alterations in NOF and PR groups and possible sirtuins’ roles. According to our studies, NOF women between 18 to 38 years old may avoid OS damage by OSR, triggering a normal signaling response and maintaining an equilibrated OS/OSR status (A). It is possible that this equilibrium favors OS during pre-menopausal aging (B). In that case, OSR are not sufficient to protect cells from OS actions and SIRT1, SIRT2 and SIRT5 gene expression increase would be required to recover homeostasis. Failing this response, women poor responders show a different sirtuin pattern (C). In this group, women between 25 to 38 years old have an imbalance between OS and OSR similar to older NOF women. Cellular attempts to reach homeostasis by increasing SIRT1, SIRT2 and SIRT5 gene expression are insufficient and it is necessary activate protein, lipid and DNA repair mechanisms and others sirtuins’ expression. Despite the fact that SIRT6 and SIRT7 gene expression increase, cells cannot response to signaling and homeostasis cannot be recovered, leading to a clinically poor response to follicle stimulation.