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Harley Weight Loss Clinic Library

Wegovy

Wegovy is a self-injectable weight loss treatment that contains semaglutide. Semaglutide mimics certain naturally-occurring hormones to help regulate blood sugar levels, which can decrease your appetite and help promote weight loss.
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  • Consult with UK GMC registered clinicians
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What is Wegovy?

Wegovy is a licensed treatment designed to help patients lose weight. It contains semaglutide, which helps to regulate your blood sugar levels. When used alongside a healthy diet and exercise programme, Wegovy can promote weight loss.

Wegovy is prescribed at specific doses to enable your body to acclimatise to the medication before taking high doses. It’s administered via injection in the stomach, thigh, or upper arm.

Wegovy is designed to help people lose weight. While it’s also used to treat diabetes under the alternative name of Ozempic, Wegovy is only prescribed as a weight loss treatment.

Wegovy is a synthetic version of the glucagon-like peptide 1 (GLP-1) gut hormone. This hormone occurs naturally, and is released after you eat to regulate your blood sugar levels. This helps to reduce feelings of hunger and cravings. By mimicking this hormone, Wegovy can also reduce your appetite.

Wegovy can also slow down your digestive processes, making your stomach empty less quickly and keeping you fuller for longer.

When used alongside healthy changes to diet, activity levels, and lifestyle, clinical trials indicate that Wegovy can help patients lose up to 15% of their body weight over the course of a year. Wegovy may also improve your heart health.

While Wegovy starts working immediately, it can take a few weeks to feel the effects. You may need to gradually increase your dose.

It’s important to make sustainable lifestyle changes to your diet and exercise routine to maintain long-term results.

You may be eligible to use Wegovy if you have a high BMI and are therefore classed as overweight (BMI >27) or obese (BMI >30).

All patients must undergo a clinical assessment to ensure their suitability before being prescribed Wegovy.

Wegovy and Ozempic are the same medication and contain the same active ingredient (semaglutide), but are prescribed for different conditions. While Wegovy is normally used for weight loss, Ozempic is prescribed as a treatment for type 2 diabetes.

Wegovy is injected under the skin in the stomach, thigh, or upper arm. You’ll administer a single injection once a week at the dose prescribed by your clinician.

Your Wegovy dosage will change over time so your body can adjust to the medication. Always make sure you’re using the right dosage at the right time, and check the needle isn’t bent or damaged in any way. It’s also important to check the medication isn’t frozen and doesn’t contain visible debris or particles before use.

Injecting Wegovy may seem daunting at first, but your clinical team will support you to ensure you feel confident in the process.

Some Wegovy users report feeling nauseous or unwell when they start using the treatment. By starting at a low dose and gradually increasing it over time, your body can adjust to the medication while minimising the risk and severity of side effects.

This also means you can stay on the lowest effective dose if preferred.

Wegovy should be stored in the fridge (at 2°C to 8°C) before your first dose. You can then keep it at room temperature for up to 6 weeks, or continue to store it in the fridge.

Do not freeze Wegovy. If it freezes, do not use it.

You should not use Wegovy if:

  • You’re pregnant or breastfeeding;
  • You have certain gastrointestinal conditions;
  • You have a history of pancreatitis or thyroid cancer;
  • You’re allergic to semaglutide or any other ingredients in this treatment.


Women should also stop taking Wegovy at least two months before trying to get pregnant or starting IVF.

All patients seeking weight loss treatment must disclose a full accurate medical history. Certain conditions or medications can make Wegovy unsuitable for you, which is why it’s important to tell your prescribing clinician so they can ensure any prescribed treatments are safe for you to use.

Like all medicines, Wegovy is known to cause some side effects. The most common side effects of Wegovy include:

  • Nausea and vomiting
  • Diarrhoea
  • Constipation
  • Fatigue and headaches
  • Lightheadedness

Other side effects include:

  • Gastroesophageal reflux (GER) and heartburn
  • Low blood sugar
  • Hair loss
  • Gallstones
  • Redness and swelling at the injection site

Rare side effects can also occur. These include pancreatitis (inflammation of the pancreas) and anaphylaxis (extreme allergic reaction). If you have severe stomach pain, difficulty breathing, or swelling of the lips, face, or tongue, seek immediate medical attention.

Find out more about the potential side effects of Wegovy in the Patient Information Leaflet

Most Wegovy side effects are mild and manageable, and will disappear as your body adjusts to the treatment. Slowly increasing your Wegovy dose (rather than starting with a higher dose) helps your body to acclimatise, reducing the risk and severity of side effects.

If using Wegovy makes you feel unwell, there are ways to manage these side effects:

  • Inject yourself at the same time every week to ensure a regular interval between doses.
  • If you feel nauseous, sip water regularly and eat smaller meals more often.
  • Increase fibre in your diet to ensure regular bowel movements if you have constipation.
  • Exercise can help with constipation and fatigue, as well as contributing to a healthy lifestyle that supports your weight loss goals.

Yes. Wegovy is only available on prescription in the UK.

Changing your diet and increasing physical activity to ensure you use more calories than you eat can help with weight loss. Lifestyle changes are important even if you do use medical treatments, as these will help you maintain a healthy weight in the long-term.

Certain treatments may also help support your weight loss journey. These medicines work in a similar way, though they contain different active ingredients. Some weight loss treatments are available as tablets rather than injectable medications.

Any patient considering medical weight loss treatment should only do so under clinical supervision, and after a complete eligibility assessment.

Medically reviewed

Last reviewed on 31/12/2025

This content has been medically reviewed to ensure clinical accuracy, evidence-based guidance, and alignment with current best practice in metabolic, liver, and lifestyle medicine.

Approved by:

Dr. Saima Ajaz
BSc, MBBS, MPhil, PhD, Dip IBLM/BSLM, DABRM

Approved by:

Dr. Saima Ajaz
BSc, MBBS, MPhil, PhD, Dip IBLM/BSLM, DABRM

Dr Saima Ajaz is a specialist hepatologist and Lifestyle Medicine Physician at the Institute of Liver Studies, King’s College Hospital, and an Honorary Senior Clinical Lecturer at King’s College London. She brings over 20 years of clinical and research experience in metabolic health, fatty liver disease, and chronic metabolic disorders, integrating lifestyle, nutrition, and personalised medicine into patient-centred care.