Erectile dysfunction (ED) is a common concern for men with type 2 diabetes and obesity, and many patients wonder: does Mounjaro cause erectile dysfunction? Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist licensed in the UK for managing type 2 diabetes and weight loss. Whilst ED is not listed as a recognised adverse effect of tirzepatide in UK regulatory guidance, understanding the relationship between metabolic health, weight loss, and sexual function is essential. This article examines the evidence, explores how Mounjaro may influence erectile function, and provides practical guidance on managing sexual health concerns whilst taking this medication.

What Is Mounjaro and How Does It Work?

Mounjaro (tirzepatide) is a prescription medication licensed in the UK for the treatment of type 2 diabetes mellitus in adults. It is also licensed for weight management in adults with obesity (BMI ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) with at least one weight-related comorbidity, as an adjunct to diet and exercise.

Mounjaro belongs to a novel class of medicines known as dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists. By activating both GIP and GLP-1 receptors, Mounjaro enhances insulin secretion in response to meals, suppresses glucagon release, slows gastric emptying, and reduces appetite—leading to improved glycaemic control and significant weight loss.

The medication is administered once weekly via subcutaneous injection, typically in the abdomen, thigh, or upper arm. Clinical trials have demonstrated that tirzepatide can lead to substantial reductions in HbA1c levels and body weight compared with placebo and other diabetes medications. The Medicines and Healthcare products Regulatory Agency (MHRA) has approved Mounjaro for use in the UK, and the National Institute for Health and Care Excellence (NICE) has issued guidance on its use within the NHS for eligible patients.

Common adverse effects include gastrointestinal symptoms such as nausea, vomiting, diarrhoea, constipation, and abdominal discomfort, particularly during dose escalation. These side effects are generally mild to moderate and tend to diminish over time. Serious but rare adverse events may include pancreatitis, gallbladder disease, and hypoglycaemia (especially when used with insulin or sulfonylureas).

Importantly, tirzepatide delays gastric emptying and may reduce the absorption of oral medications, including oral contraceptives. Women using oral contraceptives should consider using non-oral or additional barrier contraception for 4 weeks after starting tirzepatide and for 4 weeks after each dose increase.

Patients are advised to report any suspected side effects to their healthcare provider or directly to the MHRA through the Yellow Card Scheme (yellowcard.mhra.gov.uk).

How Weight Loss and Diabetes Medications Affect Sexual Function

Sexual function, including erectile function, is influenced by a complex interplay of vascular, neurological, hormonal, and psychological factors. Type 2 diabetes itself is a well-established risk factor for erectile dysfunction (ED), with studies indicating that men with diabetes are approximately three times more likely to experience ED compared with those without diabetes. The underlying mechanisms include endothelial dysfunction, reduced nitric oxide availability, autonomic neuropathy, and microvascular damage—all of which impair penile blood flow and nerve signalling essential for achieving and maintaining an erection.

Obesity is another independent risk factor for ED. Excess adipose tissue contributes to systemic inflammation, insulin resistance, reduced testosterone levels, and impaired vascular function. Weight loss, conversely, has been shown to improve erectile function in many men. Evidence suggests that even modest reductions in body weight (5–10% of baseline) can lead to improvements in sexual health, partly through enhanced cardiovascular function, improved hormonal balance, and increased self-esteem.

Regarding Mounjaro specifically, tirzepatide is not listed as causing erectile dysfunction in the Summary of Product Characteristics (SmPC) or European Public Assessment Report (EPAR). No pharmacovigilance signal has established a causal relationship between tirzepatide and ED. However, the evidence remains limited as the medication is relatively new, and individual responses to medications vary. Any new or worsening symptoms should be discussed with a healthcare professional rather than discontinuing the medication without medical advice.

It is important to consider that improvements in metabolic health and weight reduction associated with Mounjaro may, in fact, have a positive impact on sexual function over time for many patients, particularly through improved vascular health and hormonal balance.

Managing Erectile Dysfunction While Taking Mounjaro

If you are experiencing erectile dysfunction while taking Mounjaro, a comprehensive assessment is essential to identify contributing factors. ED is multifactorial, and addressing underlying causes—such as poorly controlled diabetes, cardiovascular disease, hypertension, dyslipidaemia, or psychological stress—is key to effective management.

Lifestyle modifications form the cornerstone of ED management and align well with the therapeutic goals of Mounjaro. These include:

• Optimising glycaemic control: Maintaining HbA1c within target range reduces microvascular and macrovascular complications.

• Regular physical activity: Aerobic and resistance exercise improve cardiovascular health, enhance blood flow, and support weight loss.

• Healthy diet: A balanced diet rich in fruits, vegetables, whole grains, and lean proteins supports metabolic and vascular health.

• Smoking cessation and moderation of alcohol intake: Both smoking and excessive alcohol consumption are independent risk factors for ED.

• Stress management and mental health support: Anxiety, depression, and relationship issues can significantly impact sexual function. Psychological therapies, including cognitive behavioural therapy (CBT) or couples counselling, may be beneficial.

Pharmacological treatments for ED, such as phosphodiesterase type 5 (PDE5) inhibitors (e.g., sildenafil, tadalafil), are generally safe and effective in men with diabetes. These medications enhance nitric oxide-mediated vasodilation in the penis, facilitating erections in response to sexual stimulation.

Important safety considerations for PDE5 inhibitors include:

• They are strictly contraindicated with nitrate medications and riociguat due to risk of severe hypotension

• Caution is needed with alpha-blockers; follow NHS dosing guidance to minimise hypotension risk

• Seek urgent medical attention for an erection lasting more than 4 hours (priapism)

Your GP should review all your current medications, as some (including certain antidepressants, thiazide diuretics, and beta-blockers) may contribute to ED.

In some cases, alternative treatments such as vacuum erection devices, intracavernosal injections, or referral to a specialist sexual health or urology service may be appropriate if first-line therapies are ineffective or unsuitable.

When to Speak to Your GP About Sexual Health Concerns

Sexual health is an important aspect of overall wellbeing, and open communication with your GP is essential if you are experiencing erectile dysfunction or other sexual health concerns. Many men feel embarrassed or reluctant to discuss these issues, but GPs are trained to address such matters sensitively and confidentially.

You should contact your GP if:

• Erectile dysfunction is new, persistent, or worsening, particularly if it coincides with starting a new medication or changes in your diabetes management.

• You experience other symptoms such as reduced libido, difficulty with ejaculation, or pain during intercourse.

• You have concerns about the impact of Mounjaro or other medications on your sexual function.

• You notice signs of cardiovascular disease, such as chest pain, shortness of breath, or leg pain on exertion, as ED can be an early marker of systemic vascular disease.

• You are experiencing psychological distress, anxiety, or depression related to sexual function or body image.

Seek emergency medical attention if:

• You experience chest pain, severe shortness of breath, or symptoms suggestive of a heart attack (call 999)

• You have an erection lasting more than 4 hours (priapism), which requires urgent treatment

During your consultation, your GP will take a detailed medical and sexual history, review your current medications, and assess for underlying conditions. Investigations may include blood tests to evaluate HbA1c, lipid profile, and morning total testosterone levels (before 11am, with repeat testing if low). Additional hormonal tests such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin may be considered if indicated. A cardiovascular risk assessment (QRISK) is also an important component of the evaluation.

Your GP can provide evidence-based management options, including lifestyle advice, medication review, prescription of PDE5 inhibitors if appropriate, and referral to specialist services if needed. NICE guidance supports a holistic approach to managing ED in men with diabetes, emphasising the importance of addressing modifiable risk factors and providing psychological support where necessary. Remember, seeking help early can lead to more effective treatment and improved quality of life.

Frequently Asked Questions