Is berberine (a type of herbal remedy) beneficial for polycystic ovary syndrome?

This paper studied whether a combination of berberine and letrozole (Femara) improves birth rates compared to either one alone in infertile women with polycystic ovary syndrome (PCOS). Researchers reported no significant benefit in fertility outcomes when berberine and letrozole were combined.

Polycystic ovary syndrome (PCOS) is a condition in which female sex hormones are out of balance. This leads to the growth of ovarian cysts. PCOS can cause problems such as irregular periods, excessive hair growth, weight gain, and infertility. Infertility treatment for PCOS includes clomiphene (Clomid) and metformin (Glucophage) which work to stimulate the ovaries to release eggs. Letrozole has also shown to benefit infertile women by inducing an egg to mature and be released. Berberine is an active component of a Chinese herb that is commonly used in China for diarrhoea and infertility. It has been suggested that berberine with letrozole could be a beneficial combination for women with infertility. 

644 women with PCOS and at least 1 year of infertility were studied. Women were randomly assigned to receive either letrozole alone, berberine alone, or a combination of the two. Treatment continued for up to 6 months.

A total of 199 live births were recorded. The rate of live births was similar between women receiving letrozole alone and those receiving both letrozole and berberine. 36.3% of women receiving letrozole alone had a live birth. 22% of women receiving berberine alone had a live birth. 34.4% of women receiving both letrozole and berberine had a live birth.

Women receiving letrozole alone were 68% more likely to have live birth than women receiving berberine alone. Women receiving the combination treatment were 57% more likely to have live birth than women receiving berberine alone.

No serious side effects occurred in any of the three groups. Berberine was associated with a significantly higher occurrence of constipation and nausea. Letrozole was associated with a significantly higher occurrence of fatigue and hot flashes. There were no significant differences in rates of side effects among the three groups. 

The authors concluded that adding berberine to letrozole did not significantly improve its effectiveness.