Mounjaro (tirzepatide) is a prescription medication licensed in the UK for treating type 2 diabetes. As a dual GIP and GLP-1 receptor agonist, it improves blood glucose control and promotes significant weight loss. Some patients wonder whether Mounjaro affects sexual desire or arousal. Whilst there is no established direct link between tirzepatide and increased libido, the substantial weight loss and metabolic improvements associated with treatment may indirectly influence sexual health through hormonal, cardiovascular, and psychological pathways. This article examines the evidence, explores potential mechanisms, and provides guidance on when to seek medical advice.

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. It belongs to a novel class of medicines known as dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists. This dual mechanism distinguishes Mounjaro from other GLP-1 receptor agonists such as semaglutide (Ozempic, Wegovy).

The medication works by mimicking the action of two naturally occurring incretin hormones. GLP-1 stimulates insulin secretion when blood glucose levels are elevated, suppresses glucagon release, slows gastric emptying, and reduces appetite. GIP also enhances insulin secretion and may influence fat metabolism and energy balance. Together, these actions help to improve glycaemic control in people with type 2 diabetes and promote significant weight loss by reducing hunger and caloric intake.

Mounjaro is administered as a once-weekly subcutaneous injection, starting at 2.5 mg for 4 weeks (for tolerability, not glycaemic control). The dose is then increased by 2.5 mg every 4 weeks (5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg) as tolerated, with a maximum dose of 15 mg weekly. Clinical trials have demonstrated substantial reductions in HbA1c and body weight.

It is important to note that Mounjaro is a prescription-only medicine regulated by the MHRA. It should only be used under the supervision of a qualified healthcare professional as part of a comprehensive treatment plan that includes dietary modification, physical activity, and behavioural support. Mounjaro is not indicated for patients with type 1 diabetes or diabetic ketoacidosis.

Why Weight Loss Medications May Influence Sexual Health

Weight loss medications like Mounjaro can indirectly influence sexual health and libido through several interconnected pathways, though there is no official link established between tirzepatide and increased sexual desire or arousal. Understanding these potential mechanisms requires consideration of the broader physiological and psychological effects of significant weight reduction.

Metabolic and hormonal changes associated with weight loss may play a role. Obesity is often linked to hormonal imbalances, including reduced testosterone levels in men and altered oestrogen metabolism in women. As individuals lose weight, hormonal profiles may normalise, potentially improving sexual function and desire. Additionally, improved insulin sensitivity and glycaemic control—key benefits of Mounjaro—can enhance vascular health, which is crucial for sexual arousal and erectile function in men.

Psychological factors are equally important. Many people experience improved self-esteem, body image, and mood following significant weight loss. Reduced anxiety and depression, which are common comorbidities of obesity, may contribute to enhanced libido and sexual satisfaction. The sense of achievement and increased energy levels that often accompany weight loss can also positively influence intimate relationships and sexual confidence.

Cardiovascular improvements resulting from weight loss—such as better blood pressure control, reduced inflammation, and improved endothelial function—support healthy blood flow throughout the body, including to the genital region. This vascular benefit may enhance sexual response in both men and women.

It is essential to recognise that any changes in sexual health during Mounjaro treatment are likely multifactorial and related to overall health improvements rather than a direct pharmacological effect of the medication itself. Individual experiences vary considerably, and not everyone will notice changes in libido or sexual function.

Women using combined oral contraceptives should be aware that Mounjaro may reduce contraceptive effectiveness. Additional contraception (non-oral or barrier methods) is recommended for 4 weeks after starting treatment and for 4 weeks after each dose increase. Mounjaro is not recommended during pregnancy, and women planning pregnancy should discuss this with their healthcare provider.

Common Side Effects of Mounjaro to Be Aware Of

Like all medications, Mounjaro can cause side effects, though not everyone experiences them. The most frequently reported adverse effects are gastrointestinal in nature and typically occur during the initial weeks of treatment or following dose increases. According to the UK product information, these include:

• Nausea (very common, affecting more than 1 in 10 people)

• Diarrhoea and constipation (very common)

• Vomiting and abdominal pain (common)

• Reduced appetite and indigestion (common)

• Flatulence and bloating (common)

These symptoms are generally mild to moderate and tend to improve as the body adjusts to the medication. Staying well-hydrated and eating smaller, more frequent meals may help minimise gastrointestinal discomfort.

Hypoglycaemia (low blood sugar) can occur, particularly when Mounjaro is used in combination with other diabetes medications such as sulphonylureas or insulin. Symptoms include trembling, sweating, confusion, palpitations, and hunger. Patients should be educated on recognising and managing hypoglycaemia, and dose adjustments of concomitant medications may be necessary.

Other notable side effects include:

• Injection site reactions (redness, itching, swelling)

• Fatigue and dizziness

• Headache

• Increased heart rate (tachycardia)

Serious side effects require immediate medical attention. These include signs of pancreatitis (severe, persistent abdominal pain radiating to the back), gallbladder problems (pain in the upper right abdomen, fever, jaundice), severe allergic reactions (difficulty breathing, swelling of face or throat), and changes in vision (which may indicate diabetic retinopathy complications).

Severe gastrointestinal symptoms may lead to dehydration and acute kidney injury in some patients. Those with pre-existing diabetic retinopathy should be monitored closely for worsening of their condition.

Animal studies have shown thyroid C-cell tumours with tirzepatide, although the relevance to humans is unknown. Patients should report any symptoms such as a lump in the neck, persistent hoarseness, or difficulty swallowing.

Patients and healthcare professionals are encouraged to report suspected adverse reactions via the MHRA Yellow Card Scheme. Regular monitoring by your healthcare team helps ensure safe and effective use of Mounjaro.

When to Speak to Your GP About Mounjaro and Sexual Health

If you are taking Mounjaro and notice changes in your sexual health—whether positive or negative—it is important to have an open and honest conversation with your GP or healthcare provider. Sexual health is an integral component of overall wellbeing, and your doctor can help determine whether any changes are related to the medication, weight loss, underlying health conditions, or other factors.

You should contact your GP if you experience:

• New or worsening sexual dysfunction, such as reduced libido, erectile difficulties, or problems with arousal or orgasm

• Unexpected changes in sexual desire that concern you or affect your relationships

• Symptoms that may indicate hormonal imbalances, such as irregular menstrual periods, breast tenderness, or mood changes

• Psychological concerns including depression, anxiety, or body image issues that impact your intimate life

Seek urgent medical attention if you experience:

• Severe, persistent abdominal pain (with or without vomiting)

• Signs of gallbladder disease (pain in upper right abdomen, fever, yellowing of skin/eyes)

• Sustained vomiting or diarrhoea leading to dehydration

• Severe or recurrent hypoglycaemia

Your doctor can conduct a thorough assessment, which may include reviewing your medication regimen, checking hormone levels, assessing cardiovascular health, and evaluating psychological factors. In some cases, adjustments to your treatment plan or referral to a specialist (such as an endocrinologist, urologist, or NHS sexual health clinic) may be appropriate. Erectile dysfunction may indicate underlying cardiovascular risk and merits assessment in primary care.

Women using oral contraceptives should discuss additional contraceptive methods with their GP, as Mounjaro may reduce the effectiveness of these medications. If you are planning pregnancy, inform your doctor as Mounjaro is not recommended during pregnancy and requires preconception planning.

Do not stop taking Mounjaro without consulting your healthcare provider, even if you experience side effects. Abrupt discontinuation can affect your diabetes control. Your doctor can work with you to find solutions that balance therapeutic benefits with quality of life.

Remember that sexual health concerns are common and nothing to be embarrassed about. Healthcare professionals are trained to discuss these matters sensitively and confidentially. Seeking timely advice ensures that any issues are addressed promptly and that you receive the support you need.

Frequently Asked Questions