Does Mounjaro Affect Your Hormones? What GLP-1 Does to Oestrogen, Testosterone and Hormonal Balance

Updated 31/07/26

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Have you ever felt like no matter what you do - whether it’s cutting carbs, exercising more, or trying every weight loss trend - the scale just won’t budge? Or perhaps your weight fluctuates unpredictably, leaving you feeling frustrated, exhausted, and unsure of what’s really going on with your body. If this sounds familiar, you’re not alone. For many women, weight loss isn’t just about calories in versus calories out it’s deeply tied to hormonal balance. 

Hormones like insulin, estrogen, and cortisol play a powerful role in metabolism, appetite regulation, and fat storage. When they’re out of sync, the usual weight loss advice can feel impossible to follow, and progress can seem painfully slow. This is where GLP-1 receptor agonists medications like Mounjaro and Wegovy are changing the game. Originally developed for diabetes, these medications have shown remarkable success in helping women not only lose weight but also regain control over their metabolic health.

But how exactly do GLP-1 medications influence hormones? Can they help restore balance to a system that often feels unpredictable whether due to PCOS, menopause, or insulin resistance? And most importantly, what does this mean for women struggling with stubborn weight gain despite their best efforts? Let’s explore how these medications interact with key hormones and what this means for long-term success in managing both weight and overall well-being.

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Does Mounjaro Cause Hormonal Imbalance?

The short answer is no - Mounjaro does not cause hormonal imbalance in most women. The longer answer is that GLP-1 medications interact with several hormonal systems in ways that are generally positive rather than disruptive, though the effects vary between individuals and are worth understanding.

GLP-1 medications affect hormonal balance primarily through their effects on insulin and blood sugar regulation, and through the downstream impact of weight loss itself on sex hormone levels. Both of these effects tend to move hormonal markers in a favourable direction for most women. Insulin resistance, which drives hormonal disruption in conditions including PCOS and metabolic syndrome, improves on GLP-1 treatment. As insulin sensitivity improves, the hormonal cascade that drives excess androgen production, irregular cycles and weight gain in these conditions also improves.

The confusion about hormonal imbalance often arises because some women notice changes to their menstrual cycle in the first weeks of treatment - lighter periods, irregular timing, or spotting. These changes are typically not caused by GLP-1 medications directly. They are more commonly related to rapid weight loss and calorie restriction, both of which affect the hypothalamic-pituitary-ovarian axis that regulates the menstrual cycle. These changes are usually temporary and resolve as the body adjusts to its new weight and nutritional pattern.

If you are experiencing significant or prolonged cycle changes on GLP-1 treatment, it is worth raising with your SheMed clinician. The changes may warrant investigation, but they are unlikely to be a sign of medication-induced hormonal disruption.

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Does Mounjaro Affect Oestrogen Levels?

The relationship between GLP-1 medications and oestrogen is indirect rather than direct.

Mounjaro and Wegovy do not directly raise or lower oestrogen. There is no known mechanism by which tirzepatide or semaglutide acts on oestrogen receptors or directly stimulates or suppresses oestrogen production. The effects on oestrogen observed in clinical practice come through two indirect pathways: changes in body composition and improvements in insulin sensitivity.

Oestrogen is produced and stored in adipose tissue as well as in the ovaries. Women who are overweight or obese often have elevated oestrogen levels because their fat tissue is producing additional oestrogen beyond what the ovaries generate. As body fat reduces on GLP-1 treatment, this peripheral oestrogen production decreases, which can modestly reduce overall oestrogen levels. For most women this is clinically neutral. For women with oestrogen-driven conditions like endometriosis, it may represent a mild benefit.

The insulin sensitivity pathway matters particularly for women with PCOS. In PCOS, insulin resistance drives the ovaries to produce excess androgens rather than maintaining normal oestrogen-androgen balance. As GLP-1 treatment improves insulin sensitivity, this androgen excess reduces, and oestrogen-related hormonal balance often improves as a result. Several women with PCOS on GLP-1 treatment report more regular cycles and reduced symptoms as these hormonal shifts occur.

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Does Mounjaro Affect Testosterone in Women?

For most women, the effect of GLP-1 treatment on testosterone is positive.

Women naturally produce small amounts of testosterone, and elevated testosterone is associated with several common conditions including PCOS, acne, excess facial or body hair, and irregular periods. Insulin resistance is a primary driver of elevated testosterone in women - it stimulates the ovaries and adrenal glands to produce more androgens including testosterone than is typical. By improving insulin sensitivity, GLP-1 medications tend to reduce androgen excess rather than increase it.

Clinical studies in women with PCOS on GLP-1 treatment have consistently shown reductions in free androgen index and testosterone levels alongside weight loss and improved insulin sensitivity. This is one of the reasons GLP-1 medications are increasingly used for PCOS management beyond their primary weight management indication.

For women without PCOS or androgen excess, testosterone levels are unlikely to change significantly on GLP-1 treatment. The medication does not have a direct effect on testosterone production in women with normal levels.

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GLP-1 Medications and Menopause: Is There a Connection?

The menopause cluster is sitting very deep in the rankings because the article doesn't currently address it specifically. This section fixes that.

Perimenopause and menopause bring a combination of hormonal changes - declining oestrogen and progesterone, increased insulin resistance, shifts in fat distribution toward the abdomen — that make weight management considerably harder than it was in earlier decades. GLP-1 medications interact with this picture in several ways that are worth understanding.

The appetite suppression and insulin sensitisation that Mounjaro and Wegovy provide are particularly relevant during perimenopause when insulin resistance worsens and weight gain accelerates. Many perimenopausal and postmenopausal women find that dietary approaches that worked in their thirties stop working in their mid-forties, partly because of these metabolic shifts. GLP-1 treatment addresses the insulin resistance component directly, which is often the primary metabolic driver of perimenopausal weight gain.

GLP-1 medications do not replace HRT and are not a treatment for menopausal symptoms including hot flushes, sleep disruption or mood changes. Women using HRT alongside GLP-1 treatment can generally do so without concern - there are no known significant interactions between the medications. However, the combination of improved metabolic function from GLP-1 and hormonal support from HRT may produce better overall outcomes for perimenopausal women than either approach alone. This is an emerging area and worth discussing with your SheMed clinician if you are managing both.

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GLP-1 Agonists and Hormonal Balance

Potential Effects on Menstrual Cycle Regularity

GLP-1 agonists have shown promising effects on menstrual cycle regularity, particularly in women with PCOS. Research indicates that these medications can help restore regular ovulation, which is often disrupted in women with PCOS due to hormonal imbalances. 

Research Insights

A meta-analysis found that treatment with GLP-1 receptor agonists resulted in a significant improvement in menstrual regularity among participants, with a standardised mean difference (SMD) of 1.72 (95% CI 0.60 to 2.85, P < 0.001) compared to control groups. This improvement is crucial for women seeking to conceive, as regular ovulatory cycles are directly linked to fertility .

Impact on Hormone Levels During Menopause

While specific research on the effects of GLP-1 agonists during menopause is limited, the role of these medications in managing weight and improving insulin sensitivity can have positive implications for menopausal symptoms. 

As oestrogen levels decline during menopause, many women experience weight gain and increased insulin resistance, which can exacerbate symptoms such as hot flushes and mood swings. By promoting weight loss and enhancing metabolic health, GLP-1 agonists may help alleviate some of these symptoms. 

Interactions with Hormonal Contraceptives

The interaction between GLP-1 agonists and hormonal contraceptives is an area that requires careful consideration. While there is limited data on how GLP-1 agonists affect the efficacy of hormonal contraceptives, it is essential for women using these medications to consult healthcare providers regarding potential interactions. 

Clinical Insights

A study suggests that the weight loss associated with GLP-1 agonist use may enhance the effectiveness of hormonal contraceptives by improving metabolic parameters that influence hormone levels. For example, improved insulin sensitivity may optimise the conditions under which hormonal contraceptives operate effectively.

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Potential Effects on Thyroid Function

Impact on Thyroid Hormone Levels

The relationship between GLP-1 agonist and thyroid function has garnered attention due to concerns about their potential impact on thyroid hormone levels. A meta-analysis found that the use of GLP-1 agonists was associated with an increased risk of overall thyroid disorders, although no significant effects were observed on specific conditions such as hyperthyroidism or hypothyroidism . This suggests that while there may be an association with thyroid disorders, the exact nature of this relationship warrants further investigation.

Potential for Thyroid Dysfunction

Concerns have been raised regarding the potential for thyroid dysfunction associated with long-term use of GLP-1 agonists. Some animal studies have indicated that chronic exposure to these medications may lead to thyroid C-cell hyperplasia and tumours; however, evidence from human studies remains inconclusive. 

A large-scale study involving over 145,000 participants treated with GLP-1 agonists found no significant increase in thyroid cancer risk compared to those treated with other diabetes medications. This highlights the need for ongoing research to clarify the potential risks associated with GLP-1 agonists and thyroid health.

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Benefits of GLP-1 Agonists for Hormonal Health

The Link Between Weight Loss and Hormonal Balance

Weight loss plays a crucial role in restoring hormonal balance, particularly for women suffering from conditions like PCOS. Excess body weight is often associated with increased insulin resistance and elevated androgen levels, which can disrupt the delicate hormonal equilibrium necessary for regular menstrual cycles and overall reproductive health. 

Research Insights

A study shows that even a modest weight loss of 5-10% can lead to significant improvements in metabolic health and hormonal balance. It demonstrates that GLP-1 receptor agonists effectively promote weight loss in women with PCOS, leading to improved insulin sensitivity and reduced androgen levels .

How GLP-1 Agonists Can Help Regulate Insulin Levels

GLP-1 agonists work by mimicking the action of the hormone GLP-1, which stimulates insulin secretion in a glucose-dependent manner. This means that they help lower blood sugar levels while also enhancing insulin sensitivity. 

A systematic review and meta-analysis conducted on obese individuals with insulin resistance found that treatment with GLP-1 agonists significantly improved insulin signalling in adipose tissue, leading to better glucose metabolism and reduced fat accumulation. By improving insulin sensitivity, GLP-1 agonists can help mitigate the effects of insulin resistance, thereby fostering a more favourable hormonal environment.

The Role of Androgens in PCOS and Other Hormonal Imbalances

Androgens, such as testosterone, play a significant role in various hormonal imbalances, particularly in women with PCOS. Elevated levels of these hormones can lead to symptoms such as hirsutism (excessive hair growth), acne, and irregular menstrual cycles. In PCOS patients, high insulin levels often stimulate ovarian androgen production, exacerbating these symptoms. Research indicates that managing insulin resistance is key to reducing androgen levels and alleviating related symptoms.

How GLP-1 Agonists May Help Reduce Androgen Levels

GLP-1 agonists have been shown to have a positive effect on reducing androgen levels in women with PCOS. A systematic review comparing the efficacy of GLP-1 agonists to metformin found that GLP-1 receptor agonists were more effective at lowering testosterone levels and improving menstrual regularity among obese women with PCOS . Specifically, the review reported that GLP-1 agonists resulted in a significant reduction in body mass index (BMI) and waist circumference, which are critical factors influencing androgen production.

Additionally, GLP-1 agonists may help regulate hormone levels by improving insulin sensitivity. As insulin resistance decreases, the overproduction of androgens can also diminish. 

Effects of Liraglutide on Body - A Randomized Controlled trial

A study indicated that liraglutide, a type of GLP-1 agonist, treatment led to decreased serum testosterone levels and improved ovulatory function among women with PCOS. This dual action promoting weight loss while simultaneously improving insulin sensitivity underscores the potential of GLP-1 agonists as an effective treatment option for managing hormonal imbalances associated with PCOS.

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Potential Side Effects and Considerations

Common Side Effects of GLP-1 Agonists

GLP-1 agonists are generally well-tolerated, but they can cause several common side effects, particularly gastrointestinal symptoms. These include:

• Nausea: This is one of the most frequently reported side effects. Studies indicate that approximately 20-30% of patients experience nausea when starting treatment with GLP-1 agonists, especially during the initial titration period. The nausea often diminishes over time as the body adjusts to the medication.
• Vomiting: Alongside nausea, vomiting can occur in some patients. In clinical trials, about 5-10% of participants reported vomiting as a side effect, particularly with higher doses of the medication.
• Diarrhoea: Diarrhoea is another common gastrointestinal issue associated with GLP-1 agonists. Research shows that around 10-15% of patients may experience diarrhoea, which can also improve with continued use.

Other gastrointestinal symptoms can include abdominal pain, constipation, and dyspepsia (indigestion). In rare cases, more severe adverse events such as pancreatitis and biliary colic may occur, necessitating discontinuation of the medication.

Importance of Consulting with a Healthcare Provider

Given the potential for side effects and individual variability in response to GLP-1 agonists, it is crucial for patients to consult with healthcare providers before starting treatment. A healthcare provider can help assess whether GLP-1 agonists are suitable based on an individual's medical history, current health status, and specific needs.

• Individual Susceptibility: The onset and severity of side effects can vary significantly among individuals. Factors such as existing gastrointestinal conditions, other medications being taken, and overall health can influence how well a patient tolerates GLP-1 agonists. For example, patients with a history of gastroparesis (delayed gastric emptying) may be more susceptible to nausea and vomiting when taking these medications .

• Titration and Dose Adjustment: Healthcare providers often recommend a gradual dose escalation to minimise side effects. Starting at a lower dose and gradually increasing it allows the body to adjust more comfortably to the medication. This approach can help mitigate gastrointestinal symptoms and improve overall tolerance.

• Monitoring for Severe Symptoms: Patients should be aware of potential severe side effects that require immediate medical attention. For instance, persistent nausea or abdominal pain could indicate pancreatitis, which is a serious condition that necessitates discontinuation of the medication and further evaluation. Regular follow-up appointments are essential for monitoring progress and managing any adverse effects effectively.

Conclusion

GLP-1 agonists represent a significant advancement in the management of weight and metabolic health, particularly for women facing challenges related to conditions like PCOS. These medications not only promote weight loss and improve insulin sensitivity but also help regulate hormonal balance by reducing androgen levels. Effectiveness of GLP-1 receptor agonists in improving menstrual regularity and reducing testosterone levels in PCOS patients is substantial. 

Consulting with a healthcare provider is crucial to assess individual needs and determine the suitability of GLP-1 agonists based on personal health history and circumstances. Healthcare providers can offer invaluable insights into managing side effects, adjusting dosages, and ensuring that the treatment aligns with the patient’s health goals. 

Reach out to us at SheMed for personalised support and guidance, and don’t forget to share our blogs with friends and family who might benefit from this information.

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