Berberine and PCOS: a review questions the reliability of four trials

Reassessing the credibility of the trials

Earlier reviews suggested that berberine could match or outperform metformin on certain metabolic and hormonal measures in women with PCOS. This new review examines a more fundamental question: are the available trials reliable enough to support this comparison?

The authors report searching four bibliographic databases, covering publications through October 2025. The review, prospectively registered and conducted according to PRISMA guidelines, sought randomized trials of berberine supplementation in women with PCOS.

Four trials, totaling 452 participants, met the inclusion criteria. Their measurements covered metabolism, hormones and anthropometric characteristics. The abstract does not specify the comparators, doses or durations of these trials.

Why the four trials were excluded

The trials underwent independent assessment using two frameworks focused on research integrity and trustworthiness. All four were classified as having a high risk of compromised integrity and then excluded from the quantitative synthesis.

Reported concerns included a lack of trial registration, recruitment timelines deemed implausible and possible data duplication. The authors state that they requested clarification before excluding the trials but received no response that resolved these concerns.

These signals do not, on their own, demonstrate fraud. Nevertheless, they prevent the authors from treating the reported improvements in insulin resistance, lipid profiles and androgen markers as reliable.

What this means for berberine

The distinction matters: this review does not demonstrate that berberine is ineffective for PCOS. It concludes that the data examined cannot reliably determine its effectiveness. An absence of credible evidence is not evidence of no effect.

If you are considering this supplement for PCOS, this reassessment weakens the argument that it works as well as or better than metformin. It does not provide a solid basis for replacing a prescribed treatment.

Its scope remains limited to the included trials in women with PCOS. It does not allow conclusions about all other uses of berberine, its safety or its interactions.

What we can take away

For PCOS, the benefits attributed to berberine remain uncertain: the four trials included in this review were excluded over integrity concerns, not because a lack of effect had been demonstrated.