Background: The SPARK (Symptoms of PCOS ameliorated by responses to Ke-to-adaptation) pilot study investigates whether nutritional ketosis can improve repro-ductive and metabolic outcomes in women with Polyendocrine Metabolic Ovarian Syndrome (PMOS). PMOS is a common endocrinopathy characterized by anovulation, hyperandrogenism, and metabolic dysfunction. Objective: To evaluate if a ketogenic diet (KD) or exogenous ketone supplementation (KS) with Qitone™ (bis-octanoyl-(R)-1,3-butanediol) can restore ovulation and menstrual activity. Methods: This ongoing 12-week randomized trial assigns women with PMOS to either a KD or KS intervention. Assessments include body composition by DXA, metabolic and reproduc-tive biomarkers (e.g., insulin, testosterone, SHBG), and cycle tracking via basal body temperature. Results: Preliminary data from seven participants (KD: n=3; KS: n=4) show that 100% demonstrated spontaneous menstrual activity within 2–7 weeks. Full menstrual reinstatement occurred in 86% of participants (KD=3, KS=3), including those with long-standing amenorrhea. Ovulation was predicted in 43% of the cohort. Key metabolic improvements included significant insulin reductions, favorable body composition changes (fat mass loss with lean mass preservation), and enhanced neurobehavioral well-being, including reduced anxiety and improved cognitive clarity. Conclusion: Preliminary findings suggest that both sustained and intermittent ketogenic interven-tions can restore menstrual and ovulatory function through multi-node endo-crine-metabolic recovery, independent of significant weight loss. These results highlight the potential of ketogenic therapies for PMOS but require confirmation in larger trials.