This open-label, randomized, parallel-group pilot trial investigated the effects of krill oil, metformin, and their combination on adipokine profiles, cardiometabolic risk markers, and serum fatty acid composition in women with polycystic ovary syndrome (PCOS) and metabolically unhealthy obesity (MUO). Eligible women aged 19-40 years with PCOS according to Rotterdam criteria and MUO based on combined NCEP ATP-III/IDF criteria were allocated to three 8-week interventions: continuation of standard metformin therapy (MET), krill oil supplementation alone (KO), or metformin plus krill oil (METKO). Metformin users were stratified and randomized 1:1 to MET or METKO, while metformin-naive participants were assigned to KO. Krill oil (Superba Boost, Aker BioMarine) was administered at 2,000 mg/day (approximately 400 mg EPA and 240 mg DHA) and metformin at 1,000 mg/day. Primary outcomes were changes in serum adiponectin and neuregulin-4 (NRG-4) measured by ELISA. Secondary outcomes included anthropometric indices, fasting glucose, insulin, HOMA-IR, lipid profile, reproductive hormones, and detailed serum fatty acid profiling by GC-MS, as well as Mediterranean Diet Adherence Screener (MEDAS) scores. The trial aimed to provide preliminary evidence on whether adding krill oil to metformin therapy offers broader metabolic benefits than either intervention alone in women with PCOS and MUO.