Many patients prescribed Saxenda (liraglutide 3.0 mg) for weight management wonder whether the medication might affect their libido or sexual function. Whilst Saxenda is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for obesity treatment, changes in libido are not listed as recognised side effects in the UK Summary of Product Characteristics. However, the weight loss journey itself—including common side effects such as nausea and fatigue, alongside hormonal and psychological changes—may indirectly influence sexual desire. This article examines the evidence, explores potential indirect factors, and provides guidance on when to seek medical advice.

Understanding Saxenda and Its Primary Effects

Saxenda (liraglutide 3.0 mg) is a prescription medicine licensed in the UK for weight management in adults with obesity (BMI ≥30 kg/m²) or those who are overweight (BMI ≥27-<30 kg/m²) with weight-related health conditions. It is also licensed for adolescents aged 12 to <18 years weighing >60 kg with obesity. It belongs to a class of medications called glucagon-like peptide-1 (GLP-1) receptor agonists, which work by mimicking a naturally occurring hormone in the body.

The primary mechanism of action involves:

• Appetite regulation: Saxenda acts on areas of the brain that control appetite, helping patients feel fuller for longer and reducing hunger between meals

• Slowing gastric emptying: The medication delays how quickly food leaves the stomach, contributing to prolonged satiety

• Blood glucose regulation: Although primarily used for weight management, liraglutide also influences insulin secretion and glucagon suppression

Saxenda is administered as a once-daily subcutaneous injection, with the dose gradually increased over several weeks to minimise gastrointestinal side effects. The most commonly reported adverse effects include nausea, diarrhoea, constipation, vomiting, fatigue, and injection site reactions. These effects are typically most pronounced during the initial titration period and often improve as the body adjusts to the medication.

According to the UK SmPC and NICE guidance, Saxenda should be used alongside a reduced-calorie diet and increased physical activity. Treatment should be discontinued after 12 weeks on the maintenance dose if patients have not lost at least 5% of their initial body weight. Treatment duration should be based on ongoing benefit and tolerability, with limited data available beyond 2 years of use.

Seek immediate medical attention if you experience severe, persistent abdominal pain (especially if radiating to the back) with or without vomiting, as this could indicate pancreatitis, or symptoms of gallbladder disease such as right upper abdominal pain, jaundice or fever.

Understanding these primary effects provides important context when considering whether Saxenda might influence other aspects of health, including sexual function.

Does Saxenda Directly Affect Libido?

There is no established clinical evidence of a direct effect of liraglutide on libido, and libido changes are not listed in the UK SmPC. Liraglutide's mechanism of action primarily targets GLP-1 receptors involved in appetite regulation, glucose metabolism, and gastric motility.

The Summary of Product Characteristics (SmPC) approved by the MHRA and EMA does not list decreased or increased libido as a recognised side effect of Saxenda. In the extensive clinical trial programme that led to the medication's approval, changes in sexual function were not identified as a significant adverse event. This suggests that if Saxenda does influence libido, it is not through a direct pharmacological mechanism.

It is important to distinguish between direct drug effects and indirect consequences of treatment. A direct effect would involve the medication's active ingredient specifically interacting with biological systems that regulate sexual desire. In contrast, indirect effects might occur through changes in body weight, energy levels, mood, or other factors that can secondarily influence sexual function.

However, the absence of documented direct effects does not mean that patients never experience changes in libido whilst taking Saxenda. Individual responses to medications can vary considerably, and multiple factors may interact to influence sexual function during weight management treatment. Healthcare professionals should remain open to discussing these concerns with patients, even when a direct causal relationship has not been established in clinical trials. Any persistent or concerning changes in sexual function warrant proper medical evaluation to identify underlying causes.

Indirect Factors That May Influence Sexual Function

Whilst Saxenda does not directly affect libido, several indirect factors associated with the medication and weight loss journey may influence sexual function:

Gastrointestinal side effects: The most common adverse effects of Saxenda—nausea, vomiting, diarrhoea, and abdominal discomfort—can significantly impact overall wellbeing. When patients feel physically unwell, it is entirely natural for sexual desire to diminish temporarily. These symptoms are typically most pronounced during the first few weeks of treatment and often improve with time.

Fatigue and energy levels: Fatigue is a common adverse effect listed in the UK SmPC for Saxenda. Some patients report feeling more tired when starting Saxenda, particularly if they are also following a reduced-calorie diet. Fatigue is a well-recognised factor that can reduce libido. Conversely, as weight loss progresses, many individuals experience increased energy levels, which may positively influence sexual function.

Psychological and emotional factors: The weight loss journey can be emotionally complex. Some patients may experience:

• Anxiety about treatment effectiveness or side effects

• Mood changes related to dietary restrictions

• Stress associated with lifestyle modifications

• Improved self-esteem and body confidence as weight decreases

These psychological factors can have profound effects on sexual desire, either positive or negative, depending on individual circumstances.

Hormonal changes with weight loss: Significant weight loss itself may influence hormone levels, including sex hormones such as testosterone and oestrogen. Adipose tissue plays a role in hormone metabolism, and substantial changes in body composition may temporarily affect hormonal balance. This is a consequence of weight loss rather than a direct effect of Saxenda.

Relationship dynamics: Weight loss and lifestyle changes can alter relationship dynamics, which may indirectly affect intimacy and sexual function. Partners may need time to adjust to physical and behavioural changes.

What the Evidence and Patient Reports Show

The clinical evidence base regarding Saxenda and libido remains limited. The SCALE (Satiety and Clinical Adiposity – Liraglutide Evidence) clinical trials evaluating liraglutide 3.0 mg for weight management did not systematically assess sexual function as a primary or secondary outcome, and libido changes were not reported as adverse events of interest. This means there is insufficient high-quality evidence to draw definitive conclusions about the medication's impact on libido.

Anecdotal patient reports present a mixed picture. Some individuals using online forums and patient communities have reported changes in sexual desire whilst taking Saxenda, though these accounts vary considerably:

• Some patients report decreased libido, which they attribute to side effects such as nausea, fatigue, or general malaise

• Others describe improved sexual function as they lose weight, gain confidence, and experience better overall health

• Many patients report no noticeable change in sexual desire or function

It is important to interpret anecdotal reports cautiously. Patient forums often over-represent negative experiences, as individuals experiencing problems are more likely to seek support online. Additionally, correlation does not establish causation—changes in libido may coincide with Saxenda use without being directly caused by the medication.

Research on obesity and sexual function provides relevant context. Studies consistently show that obesity is associated with higher rates of sexual dysfunction in both men and women. Mechanisms include hormonal imbalances, reduced cardiovascular fitness, psychological factors, and certain obesity-related conditions such as type 2 diabetes. Therefore, successful weight loss—regardless of the method—often leads to improvements in sexual function over time.

Healthcare professionals should acknowledge that whilst there is no official link between Saxenda and libido changes, individual experiences may vary. A thorough assessment of contributing factors is essential when patients raise concerns about sexual function during treatment.

When to Seek Medical Advice

Patients experiencing changes in libido whilst taking Saxenda should feel comfortable discussing these concerns with their GP or prescribing clinician. Open communication is essential for identifying underlying causes and ensuring appropriate management.

Consider contacting your GP if you experience:

• Persistent or significant decrease in libido that affects your quality of life or relationships

• Changes in sexual function accompanied by other concerning symptoms (mood changes, fatigue, pain)

• Erectile dysfunction or other physical difficulties with sexual activity

• Relationship difficulties related to changes in intimacy

• Symptoms suggesting hormonal imbalance (irregular periods, hot flushes, changes in body hair)

Seek immediate medical attention if you experience:

• Severe, persistent abdominal pain, especially if radiating to the back, with or without vomiting (possible pancreatitis)

• Right upper abdominal pain, jaundice (yellowing of skin/eyes), or fever (possible gallbladder disease)

Your healthcare provider can conduct a comprehensive assessment to identify potential contributing factors:

• Medication review: Evaluating all current medications, as some drugs (antidepressants, blood pressure medications, hormonal contraceptives) are known to affect libido

• Physical examination: Checking for signs of hormonal imbalance or other medical conditions

• Blood tests: Assessing hormone levels (testosterone, thyroid function), vitamin deficiencies, or metabolic markers if clinically indicated

• Mental health evaluation: Screening for depression, anxiety, or stress that may impact sexual function

For erectile dysfunction, your GP may assess cardiovascular risk factors and consider referral if symptoms persist or if low testosterone is suspected.

Do not stop taking Saxenda without medical advice. If side effects are significantly affecting your quality of life, your doctor may suggest:

• Adjusting the dose or titration schedule

• Implementing strategies to manage gastrointestinal symptoms

• Addressing contributing factors such as fatigue or mood changes

• Considering alternative weight management approaches if appropriate

Remember that sexual function is influenced by multiple physical, psychological, and relational factors. A holistic approach to assessment and management offers the best opportunity to identify and address the underlying causes of any changes you experience during your weight management journey.

If you suspect Saxenda may be causing side effects, you can report this through the MHRA Yellow Card Scheme at www.mhra.gov.uk/yellowcard.

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