Tirzepatide drove nearly 20% weight loss in women with PCOS, a UK service reports

Weight loss is the single most consistent recommendation for polycystic ovary syndrome, yet it is also the hardest for many women to achieve — and until recently there was little direct evidence on whether the newest weight-loss drugs work as well in women with PCOS as in anyone else. A UK analysis published in the Journal of the Endocrine Society on August 19, 2026 offers an early answer: in a large real-world service, tirzepatide produced roughly the same substantial weight loss whether or not a woman had PCOS [s1].

The short version: tirzepatide appears to work about as well for weight loss in women with PCOS as in women without it. But this was an observational service audit, not a trial, and the numbers at the longest follow-up rest on a very small group.

What was measured

Researchers ran a retrospective open-cohort study of a digital weight-management service in the United Kingdom, including all women aged 18 and over who were prescribed tirzepatide for weight management between February 2024 and January 2025 [s1]. The full cohort was large — 54,114 women, of whom 4,241 (7.84%) reported having PCOS [s1]. PCOS was self-reported, and weight was tracked as people reached each follow-up point rather than in a fixed, complete group.

At the 10-month mark, the mean weight change in women with PCOS was −19.40% (95% confidence interval, −22.38% to −16.42%), against −18.74% (95% CI, −19.67% to −17.81%) in women without PCOS [s1]. The two figures overlap, and the authors report the difference was not statistically significant [s1]. Put plainly, PCOS did not appear to blunt the drug's effect. More than half of the PCOS group — 57.66% (95% CI, 47.44% to 68.29%) — had lost at least 20% of their body weight by 10 months [s1].

The catch: who was left at 10 months

The headline percentages come from small numbers. Only 40 women with PCOS and 397 without had reached the 10-month follow-up point when the analysis was done [s1]. That is a fraction of the thousands who started, and people who stay on a weight-loss service and keep logging results are not a random sample — they tend to be the ones for whom it is going well. A retrospective audit of a commercial service cannot correct for that, and it has no placebo arm, so some of the measured change reflects who remained rather than the drug alone.

The study also looked at engagement with the service's non-drug tools. Among women with PCOS, those who engaged digitally lost 3.42% more of their body weight in absolute terms than those who did not (95% CI, 1.71% to 5.12%; p < 0.001) [s1] — a reminder that the surrounding support, not just the injection, tracks with results.

Where this fits

The finding matters because weight sits at the centre of PCOS management. The 2023 International Evidence-based Guideline, developed across organisations spanning 71 countries, recommends healthy lifestyle measures for all women with PCOS as a baseline, framed around metabolic health rather than appearance and paired with explicit awareness of weight stigma [s2]. That guideline predates the tirzepatide data and does not endorse the drug for PCOS; incretin therapies such as tirzepatide are not approved specifically to treat PCOS, and this study did not measure the outcomes women most often ask about — ovulation, menstrual regularity, fertility or androgen-driven symptoms [s1].

What the analysis does show is that the weight-loss benefit itself does not seem to be diminished by PCOS, which had been an open question [s1]. For a condition where the standard advice — lose weight — collides with the metabolic reality that losing weight is genuinely harder, that is a meaningful signal. It is not proof. A randomised trial with a control group, following women long enough to see whether the reproductive and metabolic features of PCOS actually shift, is what would turn this early service data into clinical guidance.

For now, the honest read is narrow but useful: in a real-world setting, women with PCOS lost about as much weight on tirzepatide as women without it, and the caveats — self-reported diagnosis, no comparison group, and just 40 women at the finish line — belong in the same sentence as the number.

Sources

• [s1] Journal of the Endocrine Society — https://doi.org/10.1210/jendso/bvag177
• [s2] Journal of Clinical Endocrinology & Metabolism / Human Reproduction — https://doi.org/10.1210/clinem/dgad463