Questionable Evidence for Berberine in Polyendocrine Metabolic Ovarian Syndrome: An Integrity-Based Reappraisal

Prior systematic reviews suggest that berberine may match or exceed the effects of metformin on metabolic and hormonal outcomes in polyendocrine metabolic ovarian syndrome (PMOS; previously referred to as polycystic ovary syndrome). This review aimed to assess the reported efficacy of berberine and act as an integrity-based reappraisal of available evidence in women with PMOS. A systematic review was conducted in accordance with PRISMA guidelines and prospectively registered. MEDLINE, EMBASE, the Cochrane Library and CINAHL were searched from inception to October 2025. Randomised controlled trials examining berberine supplementation in women with polycystic ovary syndrome were eligible for inclusion. Outcomes of interest included metabolic, hormonal, and anthropometric measures. All eligible trials underwent independent integrity assessment using two validated frameworks: the Research Integrity in Guidelines and Evidence Synthesis framework and the Trustworthiness in Randomised Controlled Trials checklist. Studies rated as moderate or high risk of compromised integrity were excluded from quantitative synthesis. Authors were contacted for clarification prior to exclusion. All four trials ( n = 452) that met eligibility criteria were independently rated as high risk for compromised integrity, and were not included in quantitative synthesis. Concerns included absent trial registration, implausible recruitment timelines, and potential duplication of data. No clarifying responses were received. While improvements in insulin resistance, lipid profiles, and androgen markers were reported, these findings cannot be considered reliable given the identified concerns. Our review demonstrates that reliable conclusions regarding the efficacy of berberine in PMOS cannot be drawn from the current evidence base.