Saxenda (liraglutide 3.0 mg) is a GLP-1 receptor agonist licensed in the UK for weight management in adults with obesity or overweight with comorbidities, and in adolescents aged 12–17 years with obesity. Administered as a daily subcutaneous injection, Saxenda works by mimicking a natural hormone that regulates appetite. Patients starting new medications often wonder about potential interactions with sun exposure, particularly whether the drug might increase photosensitivity—an abnormal skin reaction to ultraviolet radiation. Understanding the relationship between Saxenda and sun exposure is important for safe medication use, especially during summer or travel to sunny destinations. This article examines current evidence on Saxenda and sun sensitivity, provides practical sun protection guidance aligned with NHS recommendations, and clarifies when to seek medical advice.

Understanding Saxenda and Potential Sun Sensitivity

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 overweight (BMI ≥27 kg/m² with weight-related comorbidities) alongside diet and exercise. It is also licensed for adolescents aged 12 to <18 years with obesity and body weight >60 kg. Saxenda belongs to a class of medications called glucagon-like peptide-1 (GLP-1) receptor agonists, which work by mimicking a naturally occurring hormone that regulates appetite and food intake. Saxenda is administered as a once-daily subcutaneous injection, typically in the abdomen, thigh, or upper arm.

When starting any new medication, patients naturally have questions about potential side effects and lifestyle considerations. One query that occasionally arises concerns whether Saxenda might increase sensitivity to sunlight or ultraviolet (UV) radiation. Photosensitivity refers to an abnormal skin reaction that occurs when certain medications make the skin more susceptible to damage from sun exposure, potentially leading to rashes, burns, or other dermatological reactions at lower UV doses than would normally cause problems.

Understanding the relationship between medications and sun sensitivity is important for patient safety, particularly during summer months or when travelling to sunny destinations. Certain drug classes—including some antibiotics (tetracyclines, fluoroquinolones), diuretics, and non-steroidal anti-inflammatory drugs—are well-established causes of photosensitivity reactions. However, the evidence base varies considerably between different medications.

This article examines the current evidence regarding Saxenda and sun exposure, provides practical sun protection guidance for patients using this medication, and clarifies when medical advice should be sought. All recommendations align with current UK clinical guidance and established dermatological practice.

Does Saxenda Increase Sun Sensitivity?

Based on current clinical evidence and the Summary of Product Characteristics (SmPC) approved by the MHRA, there is no official link between Saxenda (liraglutide) and increased photosensitivity or sun sensitivity. Photosensitivity reactions are not listed among the known adverse effects of liraglutide in either the prescribing information or post-marketing surveillance data.

The most commonly reported side effects of Saxenda relate to its gastrointestinal effects and include nausea, vomiting, diarrhoea, and constipation, which typically improve over time as the body adjusts to the medication. Other recognised adverse reactions include injection site reactions (redness, itching, or bruising at the injection site), headache, and hypoglycaemia (particularly when used alongside other glucose-lowering medications). Dermatological reactions such as rash or urticaria have been reported rarely, but these are not specifically linked to sun exposure.

Patients should rotate injection sites as recommended to minimise localised skin irritation. As with any area of skin that becomes inflamed or irritated, it is generally good practice to protect injection sites from sun exposure until any irritation has resolved.

Clinical trials and post-marketing surveillance have not identified photosensitivity as a concern with Saxenda. However, as with any medication, individual responses can vary, and patients should remain vigilant for any unusual skin reactions. If you notice any unexpected skin changes after starting Saxenda, particularly if they coincide with sun exposure, it is advisable to discuss these with your GP or prescribing clinician and report them through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk or via the Yellow Card app).

General Sun Protection Advice for Saxenda Users

Regardless of medication use, sun protection is essential for everyone to reduce the risk of sunburn, premature skin ageing, and skin cancer. The UK has seen rising rates of melanoma and other skin cancers, making sun safety a public health priority. The NHS and Cancer Research UK recommend comprehensive sun protection measures, which are equally applicable to individuals taking Saxenda.

Key sun protection strategies include:

• Use broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30 and a UVA rating of at least 4 stars. Apply generously to all exposed skin before going outdoors, and reapply regularly, especially after swimming, sweating, or towel drying.

• Seek shade during peak UV hours, typically between 11:00 and 15:00 in the UK, when the sun's rays are strongest.

• Wear protective clothing, including wide-brimmed hats, sunglasses with UV protection, and long-sleeved shirts or cover-ups when practical.

• Be particularly cautious at higher altitudes, near water, or in snowy environments where UV radiation is reflected and intensified.

• Check the UV index through weather forecasts or smartphone apps, and adjust your sun protection accordingly.

For patients using Saxenda who inject in areas that may be exposed to the sun (such as the upper arms or thighs), it is sensible to avoid injecting into skin that is sunburnt or irritated. Rotate injection sites as recommended in the patient information leaflet, and if you notice any persistent redness or irritation at an injection site, protect that area from direct sun exposure until it has fully healed.

Patients should also maintain adequate hydration, particularly during hot weather, as Saxenda's gastrointestinal side effects can occasionally lead to fluid loss through vomiting or diarrhoea.

When to Seek Medical Advice

Whilst there is no established link between Saxenda and photosensitivity, patients should be aware of situations that warrant medical attention. Contact your GP or prescribing clinician if you experience:

• Unusual skin reactions that develop after sun exposure whilst taking Saxenda, particularly if they are severe, widespread, or accompanied by blistering, swelling, or systemic symptoms such as fever.

• Persistent injection site reactions that do not resolve within a few days, or that worsen with sun exposure.

• Signs of an allergic reaction, including widespread rash, itching, difficulty breathing, or swelling of the face, lips, tongue, or throat. These symptoms require immediate medical attention and you should call 999 or attend A&E.

• Severe or persistent gastrointestinal symptoms (nausea, vomiting, diarrhoea) that may lead to dehydration, particularly during hot weather when fluid requirements are increased.

• Symptoms of pancreatitis, including severe, persistent abdominal pain that may radiate to the back, as this is a rare but serious potential side effect of Saxenda that requires urgent medical assessment.

It is also important to inform your healthcare provider about all medications and supplements you are taking, as some combinations may increase the risk of photosensitivity even if Saxenda itself does not. Certain herbal supplements, such as St John's wort, and some over-the-counter medications can cause sun sensitivity.

If you are planning travel to a sunny destination or anticipate increased sun exposure, discuss this with your prescribing clinician during your regular review appointments. They can provide personalised advice based on your individual circumstances and medical history. Never discontinue Saxenda without medical guidance, as abrupt cessation may affect your weight management programme.

If you suspect you've experienced a side effect from Saxenda, report it to the MHRA through the Yellow Card scheme at yellowcard.mhra.gov.uk or via the Yellow Card app.

Frequently Asked Questions About Saxenda and Sun Exposure

Can I use sunbeds whilst taking Saxenda?

Sunbeds emit concentrated UV radiation and are not recommended for anyone, regardless of medication use. The NHS advises against sunbed use due to the increased risk of skin cancer and premature skin ageing. There is no specific contraindication between Saxenda and sunbeds, but the general health risks of sunbed use remain.

Should I avoid injecting Saxenda before going in the sun?

There is no evidence that the timing of your Saxenda injection relative to sun exposure affects safety or efficacy. However, it is sensible to avoid injecting into skin that is already sunburnt or irritated. Continue with your regular injection schedule as prescribed, rotating sites as recommended.

Will Saxenda affect my vitamin D levels?

Saxenda does not directly affect vitamin D metabolism. However, if you are limiting sun exposure for skin protection, you may wish to discuss vitamin D supplementation with your GP. The NHS recommends that adults consider taking a daily supplement containing 10 micrograms (400 IU) of vitamin D, especially during autumn and winter. Some people at higher risk of vitamin D deficiency are advised to take a supplement throughout the year.

Can I swim or exercise outdoors whilst taking Saxenda?

Yes, physical activity is an important component of weight management and is encouraged alongside Saxenda treatment. Apply water-resistant sunscreen with at least SPF 30 and 4-star UVA protection before outdoor activities, reapply after swimming, and stay well-hydrated. Be aware that exercise in hot conditions may increase the risk of dehydration, particularly if you are experiencing gastrointestinal side effects from Saxenda.

What should I do if I get sunburnt whilst taking Saxenda?

Treat sunburn as you normally would: move to shade, cool the skin with damp cloths or a cool bath, apply moisturiser or after-sun lotion, stay hydrated, and take paracetamol or ibuprofen for discomfort if appropriate and not contraindicated for you. Avoid injecting Saxenda into sunburnt skin until it has healed. Seek medical advice if the sunburn is severe, blistering, or accompanied by fever or feeling unwell.

Frequently Asked Questions