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NCT Number: NCT07604870

Krill Oil and Metformin in Women With PCOS and Metabolically Unhealthy Obesity

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.

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Key information

Conditions

Polycystic Ovary Syndrome Adnexal Diseases Body Weight Cysts Endocrine System Diseases Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Genital Diseases Genital Diseases, Female Gonadal Disorders Neoplasms Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity, Metabolic Ovarian Cysts Ovarian Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms Urogenital Diseases

Age range

19 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 2

Primary location

Firat University, Faculty of Health Sciences, Department of Nutrition and Dietetics

Elâzığ, 23119, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Female sex, aged 19-40 years
  • Diagnosis of Polycystic Ovary Syndrome (PCOS) according to Rotterdam criteria (at least 2 of 3: oligo/anovulation, clinical/biochemical hyperandrogenism, polycystic ovaries on ultrasound)
  • Metabolically Unhealthy Obesity (MUO) defined by combined NCEP ATP-III/IDF criteria (waist circumference >88 cm plus ≥2 metabolic risk factors)
  • BMI ≥ 30 kg/m2
  • Willingness to provide written informed consent

Exclusion criteria

  • Type 1 or Type 2 diabetes mellitus
  • Thyroid disorders (uncontrolled hypo- or hyperthyroidism)
  • Renal or hepatic disease
  • Cardiovascular disease
  • Use of oral contraceptives, insulin sensitizers, lipid-lowering drugs, or omega-3 supplements in the past 3 months
  • Pregnancy or lactation
  • Allergy to fish or seafood (krill oil contraindication)
  • Participation in another clinical trial
  • Smokers or alcohol users

Treatment and study plan

Metformin Hydrochloride 1000 MG

Drug

Metformin Hydrochloride 1000 mg/day (single daily oral dose) for 8 weeks. Metformin is a biguanide antidiabetic drug that improves insulin sensitivity and reduces hepatic glucose production. Used as standard treatment for PCOS-related insulin resistance and metabolic dysfunction.

Krill oil

Dietary Supplement

Krill Oil 2 g/day (1 g twice daily, oral administration) for 8 weeks. Krill oil is a marine-derived omega-3 fatty acid supplement rich in EPA, DHA, and phospholipids with antioxidant astaxanthin. It has anti-inflammatory, lipid-modulating, and insulin-sensitizing properties relevant to PCOS and metabolic obesity management.

Primary outcomes

  1. Change in Serum Adiponectin Level

    Time frame: 8 weeks (Baseline and Week 8)

    Change in serum adiponectin concentration measured by ELISA at baseline and after 12 weeks of intervention. Adiponectin is an anti-inflammatory adipokine associated with insulin sensitivity and metabolic health.

  2. Change in Serum Neuregulin-4 (NRG-4) Level

    Time frame: 8 weeks (Baseline and Week 8)

    Change in serum neuregulin-4 (NRG-4) concentration measured by ELISA at baseline and after 12 weeks of intervention. NRG-4 is a novel adipokine linked to lipid metabolism, brown adipose tissue activity, and cardiometabolic health.

Secondary outcomes

  1. Change in Insulin Resistance (HOMA-IR)

    Time frame: 8 weeks (Baseline and Week 8)

    Change in homeostatic model assessment of insulin resistance (HOMA-IR) calculated from fasting glucose and fasting insulin levels at baseline and 12 weeks.

  2. Change in Lipid Profile (Total Cholesterol, LDL-C, HDL-C, Triglycerides)

    Time frame: 8 weeks (Baseline and Week 8)

    Changes in fasting serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride concentrations measured at baseline and 12 weeks.

Sponsors and collaborators

Lead sponsor

Firat University

Other

Registry information

Official study title

Effects of Krill Oil and Metformin on Cardiometabolic, Adipokine, Hormonal, and Fatty Acid Profiles in Women With Polycystic Ovary Syndrome and Metabolically Unhealthy Obesity: An Open-Label, Randomized, Parallel-Group Pilot Trial

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
May 22, 2026
Registry last updated
May 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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