Can you take Mounjaro if you’ve had prostate cancer?

Jump to: Understanding prostate cancer remission | How Mounjaro works | Current guidelines | Practical tips | Take home message

You can take Mounjaro (tirzepatide) if you’re in complete remission from prostate cancer and are no longer receiving active treatment.

Still, we’d recommend letting your doctor know if you start taking Mounjaro after having prostate cancer.

It’s generally recommended to wait 6-12 months after cancer treatment ends before considering taking Mounjaro.

Prostate cancer affects approximately 52,000 men in the UK annually, making it the most common cancer among men nationwide, representing 14% of all cancer diagnoses.

UK survival rates are remarkably good, with over 85% of patients surviving beyond five years across all stages combined, and nearly 100% survival for early-stage disease.

One study found that men who gained at least five pounds from five years before to one year after prostate surgery had nearly double the risk of cancer recurrence, while obesity after surgery was linked to a 1.7-fold increased risk of recurrence compared to those who maintained a healthy weight.

Additionally, healthy habits essential for supporting weight loss, such as maintaining a balanced diet based on whole foods and regular physical activity, naturally enhance overall health and may reduce the risk of cancer recurrence.

Insulin is a hormone that can increase the risk of cancer if levels are high in the body. A condition known as insulin resistance.

By losing weight through healthy habits and Mounjaro, you can reduce insulin levels in the body.

Plus, losing weight and eating a healthy, balanced diet will lower chronic low-grade inflammation in the body, another risk factor for cancer recurrence.

Most prostate cancer survivors will likely respond similarly to Mounjaro as the general population, achieving 20-26% total body weight loss within 12 months.

You should not take Mounjaro if you have:

• Current active cancer or ongoing cancer treatment
• Family history of thyroid cancer or multiple endocrine neoplasia syndrome type 2 (MEN 2)
• Current diagnosis of thyroid cancer
• An eating disorder, such as anorexia or bulimia

Before starting Mounjaro after prostate cancer:

1. While not essential, it’s recommended to wait 6-12 months after completing treatment
2. Schedule a medication review covering all current medicines and supplements
3. Continue all recommended cancer follow-up appointments, including PSA testing

Let’s examine the relationship between prostate cancer remission and Mounjaro in greater detail.

Understanding prostate cancer remission

Prostate cancer remission refers to the reduction or disappearance of cancer following treatment.

NHS urologists and oncologists recognise several distinct remission categories:

Complete remission means no detectable cancer remains after treatment, often confirmed through PSA levels that remain undetectable or very low.

Biochemical remission occurs when PSA levels have fallen to a target level (typically <0.2 ng/mL after surgery or <2 ng/mL after radiation) and remain stable.

Partial remission happens when tumours shrink by at least 30% but remain detectable via imaging or biopsy.

Stable disease refers to cancer that has not grown or shrunk significantly (less than 20% change in either direction).

For Mounjaro eligibility, complete or stable biochemical remission is required.

In the UK, prostate cancer outcomes are particularly encouraging, with more than 9 in 10 men surviving for five years or more after diagnosis.

Many clinicians may recommend a waiting period of 6-12 months after completing prostate cancer treatment before starting weight management medications like Mounjaro.

This recovery period allows treatment-related effects to resolve and confirms stable remission through repeated PSA testing.

For prostate cancer specifically, monitoring remission primarily involves:

• Regular PSA blood tests every 3-6 months for the first two years
• Digital rectal examinations at scheduled intervals
• Occasional imaging studies (MRI, bone scans) if PSA levels change significantly
• Sometimes, repeat biopsies for clarification if concerns arise

It’s important to note that some prostate cancer treatments, particularly hormone therapy (androgen deprivation therapy or ADT), can lead to weight gain and muscle loss.

Up to 70% of men on long-term ADT experience weight gain, particularly around the abdomen, and many develop insulin resistance.

Research shows that 50-60% of men on ADT develop metabolic syndrome within one year of starting treatment.

These changes make effective weight management especially important for many prostate cancer survivors.

How Mounjaro works

Mounjaro (tirzepatide) is a dual-action weight-loss injection that works by lowering hunger and reducing the rewarding effects of food.

The medication mimics two hormones – GLP-1 and GIP – that your body naturally produces in response to eating.

These hormones regulate appetite through multiple mechanisms:

1. They slow gastric emptying by 30-40%, keeping food in your stomach longer so you feel fuller for longer
2. They directly signal your brain’s hypothalamus (our appetite control centre), reducing hunger sensations and food cravings
3. They improve insulin sensitivity by 20-30%, helping your body process blood sugar more efficiently and reducing blood glucose spikes that can trigger hunger

Research published in JAMA in 2024 shows that Mounjaro leads to an average weight loss of approximately 26% after 72 weeks of treatment.

For a man weighing 100 kg, this could represent approximately 26 kg of weight loss, although individual results vary based on starting BMI, diet, physical activity, and medical history.

Mounjaro offers additional benefits that may be particularly relevant for prostate cancer survivors:

Improved insulin sensitivity: This helps your body process blood sugar more effectively, which is important because metabolic syndrome can be a side effect of some prostate cancer treatments, especially androgen deprivation therapy (ADT).

Clinical trials show that Mounjaro can improve insulin sensitivity by 20-30% within 3-6 months of starting treatment.

Reduced inflammation: The medication lowers inflammatory markers, such as C-reactive protein and interleukin-6, addressing the chronic inflammation associated with both cancer risk and progression.

Preserved muscle mass: When combined with adequate protein intake (a hand-sized portion of protein at each meal, plus additional protein snacks if needed) and resistance exercise, Mounjaro may help preserve muscle while losing fat, especially important for men who have undergone hormone therapy.

The way Mounjaro works doesn’t interact with the biological mechanisms involved in prostate cancer development or progression.

The hormones it mimics affect hunger regulation and metabolic processes rather than androgen pathways or other mechanisms associated with prostate cancer.

Current guidelines

UK medical authorities have established clear guidelines regarding Mounjaro eligibility for cancer patients and survivors:

You can’t take Mounjaro if you have:

• A current cancer diagnosis requiring treatment
• A personal or family history of medullary thyroid carcinoma (MTC)
• Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
• A current thyroid cancer diagnosis

You can take Mounjaro if:

• You’ve completed all prostate cancer treatments (surgery, radiation, hormone therapy)
• Your urologist or oncologist has documented complete remission in your medical records
• A minimum of 6 months has passed since your active treatment ended (12 months recommended)
• You meet standard eligibility criteria (BMI ≥30 or ≥27 with weight-related conditions)
• Your PSA levels remain at target levels on consecutive tests

The Medicines and Healthcare products Regulatory Agency (MHRA) has not identified any specific contraindications for GLP-1 medications in cancer survivors who meet these criteria.

The National Institute for Health and Care Excellence (NICE) acknowledges that clinical trials for Mounjaro excluded patients with a recent history of cancer.

However, their current guidance permits use in cancer survivors in complete remission based on:

1. The medication’s known mechanisms of action
2. The absence of biological pathways that would increase cancer risk
3. The potential benefits of weight management for cancer survivors

For prostate cancer survivors specifically, maintaining a healthy weight is often recommended as part of a strategy to reduce recurrence risk and manage treatment side effects.

This potential benefit makes effective weight management tools particularly valuable for prostate cancer survivors, especially those who have undergone hormone therapy and experienced metabolic changes as a result.

Practical tips

1. Keep in touch with your healthcare team

Maintaining open communication with your medical providers is crucial.

We recommend informing your GP, urologist, and oncologist that you’re starting Mounjaro.

Second Nature’s monthly check-in forms, reviewed by our clinical team, provide an additional layer of safety monitoring throughout your treatment.

These regular assessments help identify any concerns early, ensuring your medication experience remains safe and effective.

Continue regular PSA monitoring as recommended by your specialist—typically every 3-6 months initially, then annually once the levels are stable.

Report any significant PSA changes or new symptoms promptly.

2. Eat a diet based on whole foods

Nourishing your body with nutrient-dense foods becomes especially important when taking Mounjaro after prostate cancer treatment, particularly if you’ve undergone hormone therapy.

Second Nature’s balanced plate model offers a foundation to build a healthy diet on:

• Fill half your plate with a variety of non-starchy vegetables to provide essential vitamins, minerals, fibre, and plant compounds that support overall health.
• Dedicate a quarter of your plate to quality protein sources – like poultry, fish, eggs, lean red meat, tofu, or legumes – which become especially crucial during weight loss to preserve precious muscle mass.
• The remaining quarter accommodates complex carbohydrates such as brown rice, sweet potatoes, or whole grains, providing sustained energy without blood sugar spikes.
• Include a tablespoon of healthy fats – olive oil, avocado, or nuts – which help your body absorb essential nutrients.

Prostate cancer survivors should pay special attention to protein intake, aiming for at least one open-hand-sized portion in each meal, and protein-rich snacks if needed.

Adequate protein intake helps counteract the muscle loss that often occurs with hormone therapy and ageing.

3. Exercise regularly

Regular physical activity is particularly important for prostate cancer survivors, especially those who have undergone or are undergoing hormone therapy.

Research shows that resistance training 2-3 times weekly can help counteract the muscle loss and bone density reduction associated with hormone therapy.

If you’re new to exercise, consider starting gently with walking or swimming, and gradually build up your strength training routine.

Include exercises that target major muscle groups, such as the legs, chest, back, shoulders, and arms, using either body weight, resistance bands, or weights.

Even short bursts of activity throughout the day, like 10 squats while waiting for the kettle to boil or taking the stairs instead of the lift, can add up to meaningful improvements in health and function.

Take home message

Prostate cancer survivors in complete remission can safely take Mounjaro, with research suggesting weight management may reduce the risk of cancer recurrence and improve quality of life.

The healthy habits that support long-term weight loss will also improve overall health and may reduce the risk of cancer progression by:

• Lowering chronic inflammation
• Improving insulin sensitivity
• Promoting muscle preservation
• Enhancing cardiovascular health

For men who have undergone hormone therapy, weight management becomes particularly important due to the metabolic effects of treatment.

Remember these key points when considering Mounjaro after prostate cancer:

1. Ensure you’ve been declared in complete remission with stable PSA levels
2. Continue all recommended cancer follow-up care and PSA monitoring
3. Focus on preserving muscle mass through adequate protein and resistance training
4. Keep your healthcare team informed about your weight management plans
5. Take advantage of Second Nature’s clinical monitoring for ongoing safety

Second Nature’s medication programme

Second Nature provides Mounjaro as part of our Mounjaro weight-loss programme.

Why should you choose Second Nature over other providers, assuming you’re eligible?

For peace of mind.

Second Nature has worked with the NHS for over 6 years, providing weight-loss programmes across the UK.

While our Mounjaro weight-loss programme is private and not currently used by the NHS, we’ve built the programme focusing on scientific evidence, patient safety, and data security.

We hope that our 6+ years of working with the NHS and building a track record of effective weight-loss results will give you peace of mind to give us a try.