Tirzepatide plus metformin tied to weight loss and menstrual gains in small PCOS trial

A 16-week randomized trial of 60 overweight or obese Chinese women with polycystic ovary syndrome (PCOS) found that adding low-dose tirzepatide to metformin produced far more weight loss than metformin alone, along with higher rates of menstrual cycle recovery and pregnancy ^[1]. The results were published June 3, 2026, in the journal Diabetes, Obesity and Metabolism ^[1].

How the trial was set up

Sixty women with PCOS were randomly assigned to one of two groups and treated for 16 weeks ^[1]. One group took metformin at 1,000 mg twice daily ^[1]. The other took the same metformin dose plus tirzepatide 5 mg once a week ^[1]. The main outcome the researchers measured was change in body weight, and all outcomes were assessed at the start of the study and again at week 16 ^[1]. The trial was registered as ChiCTR2400090908 ^[1].

What the numbers showed

The combination group lost an average of 10.4 kg (±3.5), compared with 1.7 kg (±2.5) in the metformin-only group (p < 0.001) ^[1]. BMI fell by 4.12 kg/m² (±1.37) versus 0.68 kg/m² (±1.82) (p < 0.001) ^[1]. Visceral fat — the fat stored around internal organs, measured here as visceral adipose tissue — dropped by 34.13 cm² (±15.33) in the combination group versus 4.67 cm² (±9.59) (p < 0.001) ^[1].

More women in the combination group regained regular menstrual cycles, and the total pregnancy rate was higher (p = 0.013 and p = 0.014, respectively) ^[1]. The published summary of the results reports those statistical values but does not list the exact percentages of women in each group.

How the pregnancy results were handled

Treatment ran for 16 weeks. After that, all participants switched to metformin alone ^[1]. Women were required to use barrier contraception for 8 weeks, and pregnancy outcomes were evaluated between weeks 25 and 48 ^[1]. That means pregnancies were counted after tirzepatide had been stopped.

The context for PCOS treatment

PCOS affects roughly 11% to 13% of women of reproductive age worldwide and is a leading cause of ovulatory infertility ^[1]. Lifestyle changes remain the recommended first-line approach, and metformin is commonly prescribed because it can improve insulin sensitivity, lower androgen levels and support ovulation, though the paper describes its clinical efficacy as limited ^[1]. Other GLP-1 receptor agonists — exenatide, liraglutide and semaglutide — have also been studied in PCOS, and earlier research found that a GLP-1 drug combined with metformin outperformed metformin alone on weight, insulin resistance and menstrual regularity ^[1].

Tirzepatide, sold in the US as Mounjaro and Zepbound, is the molecule tested here. The researchers describe the 5 mg weekly dose used in the trial as low-dose.

Why it matters for patients

Weight and visceral fat sit at the center of PCOS for many women, because excess weight worsens insulin resistance, hormone imbalances and ovulation problems ^[1]. A treatment that produces more weight loss than metformin alone could, in principle, improve both metabolic and reproductive outcomes. This trial points in that direction, but its design limits how far the results can be stretched.

The study was open-label: participants and their doctors knew which treatment each woman received, which can inflate reported benefits, particularly for outcomes that depend on judgment. It was also small, at 60 women, and short, at 16 weeks of treatment. Everyone enrolled had excess weight, so the findings may not apply to women with PCOS who are at a healthy weight. All participants were Chinese and were recruited through one hospital in Chongqing, and it has not been shown whether similar results would appear in a more diverse group of women. The authors themselves describe the findings as associations.

The published summary does not report side effects or how many women dropped out of the study, and it does not say whether any of the pregnancies had complications. Those details are not yet known from the available results.

Tirzepatide was stopped before any pregnancy was counted, and contraception was required for 8 weeks after treatment ended ^[1]. The trial was not designed to answer whether the drug can be taken safely during pregnancy, and that question has not been answered here.

What happens next

The trial is still following participants for pregnancy outcomes through week 48 after enrollment ^[1]. Results from that follow-up period have not been reported. Whether the researchers or a drugmaker plan a larger trial of tirzepatide in PCOS has not been announced.