What is PCOS (Polycystic Ovary Syndrome)?
Polycystic ovary syndrome (PCOS) is one of the most common hormonal disorders affecting an estimated 1 in 10 women in the UK of reproductive age¹. The exact cause is unknown, but it’s said to be related to abnormal hormone levels in the body, including high levels of insulin (a hormone that controls glucose levels in the body)¹.
Insulin resistance can trigger higher insulin levels, which in turn lead to a production of androgens (male hormones) – hormones that worsen many of the symptoms of PCOS (including acne and hirsutism = excessive growth of hair following a male pattern distribution)².
Elevated androgen levels disrupt the normal hormonal signals that regulate the menstrual cycle, often leading to irregular or absent periods in women with PCOS².
Insulin resistance is strongly connected to weight gain and obesity¹. When insulin levels are high, the body tends to store more fat, making it harder to lose weight.
This can create a cycle where gaining weight worsens insulin resistance, leading to weight management being more difficult¹.
Symptoms can vary from person to person but if left unmanaged, PCOS can lead to long-term health issues such as type 2 diabetes, infertility, metabolic syndrome, and cardiovascular disease¹.
What is Mounjaro (Tirzepatide)?
Mounjaro (tirzepatide) works by activating two receptors called GLP-1 and GIP to increase the level of incretins (hormones) in the body².
GLP-1 helps to regulate blood glucose levels, which in turn talks to the brain to make you feel less hungry and prevent cravings. It also slows down the emptying of the stomach to keep you feeling fuller for longer².
GIP regulates energy balance in brain and fat cells, enhancing the GLP-1 effect of suppressing your appetite and improving sugar control².
How Mounjaro differs from other diabetes and weight loss medications
In contrast, both Wegovy and Ozempic contain semaglutide and act only on the GLP-1 receptor².
- Ozempic is licensed primarily for type 2 diabetes, helping to lower blood sugar and reduce cardiovascular risk².
- Wegovy uses the same active ingredient (semaglutide) but at higher doses specifically approved for weight management².
- Mounjaro is approved for type 2 diabetes and, in many markets, including the UK market, also used for weight loss².
Mounjaro's Potential Benefits for PCOS Symptoms
Impact on Insulin Resistance
Better Insulin Sensitivity = Better Hormone Balance
Insulin resistance affects 50%–70% of women with PCOS³. Since insulin resistance is a core driver of PCOS, improving insulin function is critical for long-term health and hormonal regulation³.
Mounjaro helps the body use insulin more effectively and manage blood glucose after meals.
Mounjaro can help by:
- Boosting insulin release when it’s needed and reduce the amount of glucose the liver makes²
- Slowing down digestion, helping blood glucose rise more gradually²
- It makes your body more sensitive to insulin, so it can use glucose for energy instead of it being stored as fat²
- It helps reduce body weight by making you feel less hungry, so you can improve insulin resistance²
Together, these actions improve the body’s response to glucose and help keep blood sugar and insulin levels more stable over time².
Metformin has been used for many years in PCOS and can help the body respond better to insulin, but it usually leads to only small amounts of weight loss³.
Other medicines such as pioglitazone can also improve insulin resistance, but they may cause weight gain, which can reduce some of their benefits³.
Mounjaro works differently by affecting appetite hormones and supporting weight loss, it can improve insulin sensitivity in a broader way than traditional treatments².
Weight Management Effects
Clinical evidence of tirzepatide's efficacy for weight loss:
Tirzepatide (Mounjaro) has demonstrated strong efficacy for weight loss in adults with overweight or obesity².
Significance of weight reduction in PCOS management
Weight reduction, even modest amounts (5–10% of body weight), can have a significant impact on symptom management⁴. Losing weight can improve insulin sensitivity, regulate menstrual cycles, reduce androgen levels, and help manage symptoms such as acne, excess hair growth, and irregular periods⁴. It can also enhance fertility outcomes for women trying to conceive and improve long-term metabolic and cardiovascular health⁴.
Lifestyle interventions focusing on balanced nutrition, regular physical activity, and sustainable weight loss are first-line strategies for managing PCOS⁴.
Mechanisms of action on appetite regulation and gut hormones
Many people with PCOS find losing and keeping off weight difficult. This is where Mounjaro (tirzepatide) may help². Mounjaro is a once weekly injectable medicine that can support weight loss by:
- Reducing appetite and cravings, making it easier to eat less²
- Slowing digestion, which helps you feel full for longer²
- Improving blood glucose control, which reduces spikes that can promote fat storage²
Hormonal Balance Improvements
High insulin can lead to high testosterone, which causes common PCOS symptoms like irregular cycles, acne, hair growth on the face/body (hirsutism) and thinning scalp hair³.
Mounjaro lowers insulin, and as a result, can help lower testosterone levels². A recent review found that GLP-1s may be even more effective than metformin at reducing androgens in some women⁵.
By balancing insulin and testosterone, these medications help restore more regular periods and reduce other hormonal symptoms of PCOS².
Reproductive Health and Fertility
Many women with PCOS have irregular or missing periods because they don’t ovulate regularly³. Improving insulin sensitivity can help restore more regular ovulation and menstrual cycles³.
Potential effects on menstrual cycle regulation
Weight loss improves menstrual irregularities primarily by lowering excess oestrogen levels and reducing insulin resistance, which helps restore regular ovulation, particularly in women with PCOS or obesity⁴. Losing 5-10% of body weight can correct hormonal imbalances (specifically reducing androgen levels) leading to more regular, less heavy periods⁴.
Impact on ovulation and anovulation
As mentioned above, weight loss can lead to regular ovulation⁴. Improved insulin sensitivity and reduced body fat can increase the frequency of ovulation, reducing anovulatory cycles and supporting normal reproductive function⁴.
Possible benefits for fertility outcomes
Regular ovulation and hormonal balance can enhance fertility, increasing the chance of conception and improving response to fertility treatments if needed⁴.
It is important to note, if you plan to start trying to get pregnant, you should stop taking Mounjaro at least 1 month before you plan to get pregnant. This should give you long enough to break down and remove the drug from your body.
Relationship between metabolic improvements and reproductive function
Mounjaro supports metabolic health by lowering insulin resistance and reducing visceral fat, which helps decrease androgen levels and stabilise reproductive hormones².
Relationship to overall reproductive health
Combining weight loss, metabolic improvement, and lifestyle interventions promotes long-term reproductive health, reduces complications, and improves quality of life for women with PCOS⁴.
Is it OK to use Mounjaro with Other PCOS Treatments?
- Ensuring to continue with healthy eating and regular physical activity is essential. These lifestyle changes improve insulin resistance, help with weight management, and support hormone balance, all of which are central to managing PCOS.1,3
- Mounjaro and metformin can be safely used together. Both medications improve insulin sensitivity, which is a key issue in many women with PCOS 2,6.
- Mounjaro can be used alongside birth control safely. While birth control doesn’t treat insulin resistance or weight gain, Mounjaro does, so together, they can tackle different aspects of PCOS 2,5.
- Mounjaro may help reduce the need for other PCOS medications over time — especially those used to treat insulin resistance or aid in weight loss. For example, lower insulin and testosterone levels may mean less need for anti-androgens or weight loss may improve cycles without needing cycle-regulating drugs 1,5,6
References
- Teede H.J., et al. (2018). International PCOS Guideline: 2018 update. Human Reproduction, 33(9), 1602–1618.
- Wilding J.P.H., et al. (2022). Once-weekly tirzepatide for the treatment of obesity. NEJM, 387, 205–216.
- Moran L.J., et al. (2013). Lifestyle changes in women with polycystic ovary syndrome. Cochrane Database Syst Rev, 2, CD007506.
- Lim S.S., et al. (2019). Obesity and reproductive health in women with PCOS. Endocrine Reviews, 40(5), 1–18.
- Jensterle M., et al. (2020). GLP-1 receptor agonists in the treatment of PCOS: Impact on metabolic and hormonal parameters. Nutrients, 12(6), 1785.
- Legro R.S., et al. (2007). Metformin therapy in women with PCOS: effects on insulin and ovulatory function. Fertility and Sterility, 88(2), 325–332
