GLP-1s vs. Metformin for PCOS: Weight, Cycles, and Insulin Compared
For PCOS, GLP-1 medications beat metformin on weight and waist size, and in several analyses on insulin resistance. On the outcomes that make PCOS distinct, menstrual cycles and androgen levels, trials have not shown GLP-1s doing better than metformin. Pregnancy plans often decide the rest, because GLP-1s have to be stopped well before trying to conceive.
Key takeaways
- In a large 2025 real-world analysis of 36,674 women with PCOS, median one-year weight loss was 11.5% on a GLP-1 versus 1.9% on metformin.
- Meta-analyses of randomized trials find GLP-1s lower BMI and waist size more than metformin, but show no significant difference in menstrual frequency or testosterone.
- The 2023 international PCOS guideline says metformin "should be considered" for adults with a BMI of 25 or more, and that anti-obesity medications, including GLP-1s, "could be considered" alongside lifestyle changes.
- Wegovy's label says to stop it at least 2 months before a planned pregnancy; metformin has a guideline role in anovulatory infertility.
Outcome-by-outcome comparison
| Outcome | GLP-1 medications | Metformin | How solid is the evidence? |
|---|---|---|---|
| Weight loss | Clearly greater: 11.5% median at ~1 year in real-world data | 1.9% median at ~1 year in the same data | Consistent across trials and real-world data |
| Waist / abdominal fat | Greater reduction vs. metformin | Smaller reduction | Moderate to low |
| Insulin resistance | Better than metformin in two meta-analyses; no difference vs. control in a 2026 review | Established insulin-sensitizer | Mixed |
| Menstrual frequency | No significant difference vs. metformin in pooled trials | Similar | Low to very low |
| Testosterone / free androgen index | No significant difference vs. metformin | Similar | Low |
| Trying to conceive | Stop at least 2 months before planned pregnancy (Wegovy label); use effective contraception while on it | Guideline says it can be used for anovulatory infertility | Guideline and label guidance |
| Guideline position (2023) | Anti-obesity medications "could be considered" with lifestyle | "Should be considered" if BMI 25+ | International evidence-based guideline |
| Typical self-pay cost (Oct 2026) | About $149 to $449/month | About $7 to $10/month | Manufacturer and GoodRx pricing |
Source: Epic Research (2025); Han et al. meta-analysis and later meta-analyses as summarized by InpharmD; Forslund et al., European Journal of Endocrinology (2026); 2023 International PCOS Guideline summary; Wegovy label.
Weight: the clearest win for GLP-1s
The largest comparison comes from Epic Research, which analyzed 36,674 women aged 18 to 50 with PCOS who started either a GLP-1 or metformin between 2021 and 2024. At about one year, median weight loss was 11.5% on a GLP-1 and 1.9% on metformin. More than half (55.7%) of GLP-1 users lost at least 10% of body weight, versus 13.7% of metformin users (Epic Research). The results held after adjusting for starting BMI and other factors, though this was observational data, not a randomized trial.
Randomized trials point the same way. A 2019 meta-analysis of 8 trials and 462 participants found GLP-1s reduced BMI and abdominal girth more than metformin (Han et al., as summarized by InpharmD). A 2025 meta-analysis of 13 trials reached a similar conclusion on weight, waist, and waist-to-hip ratio.
Insulin resistance: likely better, not settled
Insulin resistance drives much of PCOS, and metformin is an insulin-sensitizer by design. Even so, the 2019 and 2025 meta-analyses both found GLP-1s improved insulin sensitivity measures more than metformin. In the Epic data, 83.5% of GLP-1 users saw some HbA1c reduction, versus 55.9% on metformin.
A more cautious 2026 review of 11 trials in the European Journal of Endocrinology found no significant difference in HOMA-IR, a common insulin-resistance score, in its pooled analysis of the four studies that reported it, where GLP-1s were added to the same background treatment as the control group. It rated eight of the 11 trials at high risk of bias, and six lasted only 12 weeks.
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Cycles and androgens: no proven edge
This is the part many people expect GLP-1s to win, and the trial evidence does not yet show it. The 2019 meta-analysis found no significant difference between GLP-1s and metformin in menstrual frequency, total testosterone, or free androgen index. A 2024 meta-analysis of 8 trials comparing GLP-1s with metformin and other controls also found no significant differences on those outcomes, and the 2025 analysis found hormone improvements were not greater than with metformin (InpharmD summary).
The 2026 review found that both metformin-controlled studies reporting cycles favored GLP-1s, but rated that evidence "very low" certainty. Most metformin-controlled trials tested exenatide, an older GLP-1, rather than semaglutide or tirzepatide.
Newer research is starting to fill the gap. In June 2026, University of Colorado researchers reported early signs of improved ovulation in young people with PCOS who lost at least 10% of body weight on semaglutide. They described it as a proof-of-concept analysis needing larger studies (CU Anschutz).
For irregular cycles and excess hair growth on their own, the 2023 international guideline names the combined oral contraceptive pill as first-line drug treatment, not metformin or a GLP-1 (guideline summary).
Pregnancy plans change the answer
If you may want to conceive soon, timing matters more than effect size.
- GLP-1s: The Wegovy label says to discontinue it at least 2 months before a planned pregnancy because semaglutide stays in the body a long time. The 2023 guideline says clinicians should ensure effective contraception while taking GLP-1s, because pregnancy safety data are lacking.
- Tirzepatide and the pill: The Zepbound label advises switching to a non-oral contraceptive, or adding a barrier method, for 4 weeks after starting and for 4 weeks after each dose increase.
- Metformin: The guideline says metformin could be used alone in women with PCOS who have anovulatory infertility and no other infertility factors, while noting that letrozole is the first-line drug for ovulation induction.
Side effects
Both cause GI symptoms. The 2019 meta-analysis found nausea and headache were more frequent with GLP-1s than metformin. Metformin's own label reports diarrhea in 53% of users versus 12% on placebo in its main U.S. trial, and the PCOS guideline notes these effects are usually dose-dependent and self-limiting. The guideline also flags possible low vitamin B12 with metformin in people with other risk factors.
Using both together
This is not always either/or. Many women with PCOS start a GLP-1 on top of metformin. A 2025 meta-analysis found adding a GLP-1 to metformin lowered weight and BMI more than metformin alone, without a significant change in testosterone (InpharmD summary).
What happens after stopping? In a small Slovenian study, 25 women who took semaglutide on top of metformin for 16 weeks and then stayed on metformin regained about a third of their lost weight over two years. Free testosterone, which fell during semaglutide, did not significantly rebound. The study had no control group (Frontiers in Endocrinology, 2024).
Cost
Metformin costs about $7 to $10 a month with discount cards (GoodRx). GLP-1s cost far more without coverage: Zepbound is $299 to $449 a month with Lilly's self-pay card (Lilly), and Wegovy is $349 a month for injections, with the pill from $149 (Fierce Pharma). PCOS alone is not an FDA-approved indication for any GLP-1, so coverage usually depends on meeting the obesity criteria on the label.
The verdict
Choose based on your main goal. If weight, waist size, and metabolic risk are the priority and pregnancy is not planned in the next few months, a GLP-1 is the stronger tool, often added to metformin rather than replacing it. If you are trying to conceive soon, if cost is a barrier, or if your weight is not the main issue, metformin remains the guideline-backed, low-cost choice. For cycles and androgen symptoms specifically, neither drug has proven better than the other, and the guideline points to other first-line options. Bring these trade-offs to your prescriber or gynecologist.
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Frequently asked questions
Is a GLP-1 better than metformin for PCOS weight loss?
Yes. In a 2025 real-world analysis of 36,674 women with PCOS, median one-year weight loss was 11.5% on a GLP-1 versus 1.9% on metformin, and randomized-trial meta-analyses also favor GLP-1s for BMI and waist size.
Do GLP-1s regulate periods better than metformin in PCOS?
Not proven. Meta-analyses have found no significant difference between GLP-1s and metformin in menstrual frequency, testosterone, or free androgen index, and the available evidence is rated low to very low certainty.
Can I take a GLP-1 while trying to get pregnant with PCOS?
The Wegovy label says to stop it at least 2 months before a planned pregnancy, and the 2023 PCOS guideline advises effective contraception while on GLP-1s. Metformin has a guideline role in anovulatory infertility, with letrozole as first-line for ovulation induction.
Can you take metformin and a GLP-1 together for PCOS?
Yes, they are often combined. A 2025 meta-analysis found adding a GLP-1 to metformin lowered weight and BMI more than metformin alone. Whether it fits you is a decision for your prescriber.
Is PCOS now called PMOS?
Yes. A global consensus process published in The Lancet in May 2026 set polyendocrine metabolic ovarian syndrome (PMOS) as the new name, with the change phased in over three years, so both terms are in use.
Sources
- GLP-1s lead to greater weight loss and A1c improvement than metformin in patients with PCOS, Epic Research (2025)
- Han et al. GLP-1 receptor agonists versus metformin in PCOS: a systematic review and meta-analysis
- What are the benefits of GLP-1 agonists in patients with PCOS? InpharmD
- Forslund et al. GLP-1 receptor agonist treatment in women with PCOS, European Journal of Endocrinology (2026)
- Summary: International evidence-based guideline for the assessment and management of PCOS (2023)
- Wegovy prescribing information, FDA (2025)
- Zepbound prescribing information, Eli Lilly
- Injectable semaglutide shows early promise to improve fertility in women with PMOS, CU Anschutz (2026)
- Jensterle et al. Semaglutide withdrawal with continued metformin in PCOS, Frontiers in Endocrinology (2024)
- Teede HJ et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. The Lancet, 2026 (online May 12, 2026)
- RANZCOG welcomes PCOS renaming to PMOS (2026)
- Metformin prescribing information, Drugs.com
- Metformin prices, GoodRx
- Zepbound coverage and savings, Eli Lilly
- Wegovy pill launches at $149 per month, Fierce Pharma
Medical disclaimer: This article is general information, not medical advice, and does not replace a licensed clinician who knows your history. Approvals, labels, coverage and prices change; check the linked sources and talk with your prescriber or pharmacist before making decisions about any medication.