Semaglutide for Weight Loss

Semaglutide is a prescription-only medicine licensed for weight loss and type 2 diabetes in the UK. Wegovy is the branded name for semaglutide for weight loss. It’s an injection that is used once weekly alongside diet and exercise changes in overweight or obese individuals. Semaglutide works by suppressing your appetite, making you feel fuller for longer.

Brenda Ikeji

Medically reviewed by

Dr Brenda Ikeji

Last reviewed: 18 Sep 2024

Light grey semaglutide injection pen for weight loss, branded for Wegovy®

What is semaglutide used for?

Semaglutide is a medication used to treat type 2 diabetes and help with weight loss. It can help those with diabetes to control their blood sugar levels, and lowers the risk of heart attack and stroke in those that are overweight. It can help with weight loss by making you feel less hungry, and when used alongside other lifestyle changes can help you to lose weight.

Semaglutide is available as tablets or injections, which are used to treat diabetes or help with weight loss.

Semaglutide injections

Semaglutide injections are used to control blood sugar levels in adults with type 2 diabetes under the brand name Ozempic, and is also available as a weight loss treatment under the brand name Wegovy.

Wegovy and Ozempic work in the same way, except that Wegovy is available in a higher dose of semaglutide than Ozempic because it is more appropriate to treat weight loss with a higher dosage. You can read our doctor’s advice for more information on the differences between Ozempic and Wegovy.

Semaglutide tablets

Semaglutide is available as a tablet for diabetes under the brand name Rybelsus. It works by helping diabetic patients to control their blood sugar levels by increasing the amount of insulin the body produces. Studies have shown that Rybelsus can help people with weight loss too, but it is only currently approved for diabetes.

There is currently no semaglutide tablet approved for weight loss in the UK.

Is semaglutide available in the UK?

Yes, semaglutide is available in the UK for weight loss under the brand name Wegovy, so your doctor may refer to the semaglutide injections as ‘Wegovy’ injections.

Semaglutide is also available in the UK for type 2 diabetes as an injection called Ozempic and as tablets under the brand name Rybelsus. Rybelsus and Ozempic are not licensed for weight loss treatment.

Is semaglutide insulin?

“Semaglutide is not insulin. It is used for the treatment of type 2 diabetes and more recently weight loss. It works by mimicking the hormone glucagon-like peptide-1 (GLP-1) that’s released in response to eating. It works by prompting your body to produce more insulin to lower blood sugar levels and sends signals to your brain that reduces your appetite.”

Brenda Ikeji
Dr Brenda Ikeji Medical Editor

What does semaglutide do to your body?

Semaglutide works by imitating the GLP-1 hormone released by your gut in response to eating. So, semaglutide does the following things to your body:

  • reduces your appetite, telling your brain that you feel full, similar to what the GLP-1 hormone naturally does after you eat a meal
  • delays the emptying of your stomach, keeping you feeling full for longer, even with fewer calories
  • helps your body manage your blood sugar levels better by increasing the amount of insulin produced

It’s important to note that the semaglutide effects are the same, whether you’re taking it for diabetes 2 or weight loss. The biggest difference is that the dosage schedule is set up differently for the intended purpose:

  • Wegovy has a higher maintenance dose as this is better for weight management.
  • Ozempic is at a lower dose because this is adequate for blood sugar management. It can still cause weight loss but at a lower rate
  • Rybelsus doses are higher than both forms of injectable semaglutide because a higher dose is needed when absorbing the medicine through the stomach.

How does semaglutide work for weight loss?

Semaglutide injections for weight loss work by suppressing your appetite and keeping your stomach fuller for longer, making it easier to eat fewer calories and reduce snacking without feeling hungry all the time. They must be used alongside exercise and a low-calorie diet program for effective long-term weight management.

How long does semaglutide take to work?

Semaglutide starts to work after your first dose but it can take several weeks or months before you notice any effects. If you have not noticed any significant weight loss, at least 5% of your starting weight, after 6 months of using semaglutide, you should consider changing your treatment.

How effective is semaglutide for weight loss?

Studies into the effectiveness of semaglutide (Wegovy) as a weight loss medication show promising results. This study, carried out over 68 weeks at the maintenance dose of 2.4mg found that:

  • People lose up to 15% of their starting weight. To compare, people in the placebo group only lost an average of 2.4% of their starting weight.
  • People can lose on average 15.3kg from their baseline weight. In comparison, the placebo group lost an average of 2.6kg.
  • It’s an effective weight loss treatment for most people, with 83.5% of participants losing at least 5% or more of their starting weight. In the placebo group, only 31.1% of patients lost 5% or more of their starting weight.

In the study, participants followed a diet and exercise program, which is a requirement when taking semaglutide for weight loss. Although Wegovy and other semaglutide medications can help you lose weight, they do so by reducing your appetite so you can better manage a reduced-calorie diet and stick to it without feelings of hunger making it difficult.

How much weight can you lose in a month with semaglutide?

It is difficult to quantify how much weight you can lose in a month while using semaglutide because every individual is different and our bodies will react in different ways. It depends on how drastically you’ve changed your diet and exercise habits from before taking it, and how quickly the medicine works for you.

You could lose no weight within a month, or some, but this doesn’t mean that semaglutide isn’t working. You need to reach the maintenance dose (2.4mg) for the most effective results and it takes 17 weeks (or longer) to reach this dose.

Are semaglutide injections safe for weight loss?

Semaglutide injections are safe for weight loss for people who meet specific criteria such as a BMI over 30 or over 27 with weight-related health issues. As it’s a prescription-only medicine, your doctor will make sure it’s safe for you to take semaglutide. Like all medicines, it can cause side effects, but these should subside once your body has gotten used to the new medication.

“As semaglutide can cause side effects, the manufacturer has made it a requirement to follow the Wegovy dosage schedule, which involves increasing your dose every 4 weeks. This can minimise side effects and give your body more time to get used to the medication. You can also stay on a lower dose for longer if you need to.”

Brenda Ikeji
Dr Brenda Ikeji Medical Editor

What do you feel after taking semaglutide?

You may notice a reduced appetite or that you aren’t feeling as hungry between meals or craving food as much as before. This effect should increase the longer you take semaglutide and as you increase the dose.

Some people also report feeling sick (nausea), being sick (vomiting) or having diarrhoea when they first start using semaglutide injections for weight loss. The semaglutide dosing schedule is intended to lower the risk of experiencing these side effects, but people who do experience them often report that they go away after a few weeks of using the medication.

If you take semaglutide and are unable to tolerate the side effects, then you may need to discuss an alternative treatment with your doctor.

Can anyone take semaglutide?

Semaglutide injections are not intended for everyone – they are specifically for people who are diabetic or meet specific weight loss criteria. Even if you would like support in losing weight, if you don’t meet the criteria for treatment then semaglutide is not right for you. If this is the case, your doctor may recommend you some alternative treatments

Can I take semaglutide if I’m not obese?

If you’re not classed as obese on the BMI scale but are classed as overweight, you may still be able to take semaglutide. Doctors can only prescribe semaglutide weight loss injections to people who have a:

  • BMI of 30 or more (obese)
  • BMI between 27 and 30 (overweight) if they have a weight-related health issue, which includes prediabetes, high blood pressure and obstructive sleep apnoea

What happens when you stop taking semaglutide?

When you stop taking semaglutide for weight loss, you may regain some of the weight you have lost. For example, one study found that 52 weeks after stopping once-weekly semaglutide injections, participants had regained 66% of their prior weight loss. That’s because when you stop the medication, you will regain your appetite which can increase your calorie intake and lead to you putting the weight back on.

You can minimise the risk of weight gain after Wegovy by staying on the medication for long-term weight management, or by following a diet and exercise regime that keeps your calorie intake at a level that will prevent further weight gain. This can be difficult when your appetite comes back, which is why Wegovy is classed as a long-term treatment. You don’t need to stop taking it just because you’ve reached your weight loss goals.

If you also have type 2 diabetes, it can also mean your blood sugar levels may rise, increasing your risk of diabetes-associated adverse health effects.

How much does semaglutide cost?

Semaglutide cost will depend on where you get your prescription from. If you are eligible for semaglutide on the NHS, you may be subject to prescription charges.

Semaglutide injections are also available on a private prescription from ZAVA. The current cost of semaglutide (Wegovy) starts at £139.00 for 1 pen, which is 4 doses or 4 weeks worth of treatment. Semaglutide is available under its brand name Wegovy online and there is currently no cheaper, generic version available.

Is semaglutide safe for non-diabetics?

Yes, it is safe for doctors to prescribe semaglutide for weight loss in non-diabetics. People who are overweight or obese are at a higher risk of developing type 2 diabetes. But not everyone who is overweight or obese does become diabetic so this isn’t a requirement to be prescribed Wegovy for weight loss.

Originally, semaglutide was prescribed to lower blood sugar levels in diabetic patients (Ozempic). However, while using semaglutide, it was found that some patients were also losing weight, leading to it being licensed for weight loss in the UK for non-diabetics (Wegovy).

What are the semaglutide side effects?

Semaglutide side effects when taken in the form of Wegovy include:

Very common

  • Feeling sick (nausea)
  • Being sick (vomiting)
  • Diarrhoea
  • Constipation
  • Headache
  • Stomach pain
  • Feeling tired or weak

These side effects should go away over time.

Common

  • Dizziness
  • Upset stomach
  • Indigestion
  • Bloating
  • Gas or burping
  • Stomach inflammation (gastritis)
  • Acid reflux
  • Heartburn
  • Gallstones
  • Hair loss
  • Low blood sugar (hypoglycaemia) in people with diabetes, which is more likely if you’re taking other diabetes medications at the same time
  • Injection site reactions
  • A change in the way things taste
  • A change in skin sensations
  • Complications of diabetic eye disease in people with diabetes – this is serious and should be discussed with a doctor straight away

Uncommon

  • Increase in pancreatic enzymes
  • Delayed emptying of the stomach (gastroparesis)
  • Fast heartbeat
  • Low blood sugar in patients without diabetes
  • An increased level of bilirubin in the blood which can cause jaundice
  • An inflamed pancreas (acute pancreatitis) – see a doctor straight away if you get severe and long-lasting pain in your stomach or back
  • Kidney or bladder stones – speak to a doctor if you notice you’re finding it difficult to urinate, your urine is a different colour, or you have back or lower abdomen pain

For further information about semaglutide side effects, please refer to the Wegovy patient information leaflet.

What are the semaglutide contraindications?

Semaglutide is not suitable for everyone and you should only take it if your doctor agrees it is safe for you to do so. A doctor cannot prescribe semaglutide injections for weight loss if you are not clinically overweight, even if you are looking to lose weight.

As well as meeting the BMI criteria, semaglutide may not be suitable for you if you are:

  • Pregnant, planning to get pregnant or breastfeeding
  • Allergic to any of the ingredients in semaglutide injections or tablets for weight loss

Before prescribing semaglutide, your doctor may also ask if you have:

  • Kidney problems
  • An inflamed pancreas
  • Diabetes
  • Low blood sugar levels
  • Diabetic eye disease (retinopathy)

Why is semaglutide contraindicated in pregnancy?

Semaglutide is not recommended for pregnant women or women who are trying to get pregnant because animal studies have shown that it may cause birth defects, miscarriage, or stillbirth. There are currently no human studies available about the effects semaglutide may have on human pregnancy.

This isn’t unusual as it is not ethical to test medicines on pregnant people, but semaglutide is not recommended to be used by pregnant women. If you are worried, you should speak to your doctor for advice.

What are the risks of semaglutide?

Semaglutide may cause serious side effects, such as:

  • Thyroid tumours. You should let your doctor know immediately if you notice any lumps or swelling in your neck, have trouble swallowing or breathing, or experience a hoarse voice. The symptoms could indicate thyroid cancer.
  • Inflamed pancreas. If you experience severe pain in your stomach that doesn’t go away with or without vomiting you should seek medical advice straight away.
  • Gallbladder problems. Gallbladder problems include gallstones and you may experience pain in your upper tummy area, fever, yellowing of the skin or the whites of your eyes (jaundice), or clay-coloured stools.
  • Kidney problems. Some of the side effects associated with semaglutide like feeling or being sick and diarrhoea can increase loss of fluids which can make existing kidney issues worse.
  • Depression. You should inform your doctor if you experience any mental health changes while taking semaglutide, especially in your mood, behaviour, thoughts, or feelings.
  • Increased heart rate. Tell your doctor if you feel your heart racing or pounding, especially when at rest while using semaglutide.

Semaglutide and cancer

Semaglutide is not appropriate for people with certain types of cancers, such as thyroid cancer. Because of this, some patients feel concerned that semaglutide can give them cancer. However, studies have shown that semaglutide does not increase your risk of any type of cancer. While it may not be safe for patients with certain types of cancer to take semaglutide, it will not increase your risk of it.

Where can I buy semaglutide in the UK?

You can safely and legally buy semaglutide online from trusted healthcare services such as ZAVA. All you need to do is complete a short online assessment and answer a few questions about your health. Our team of UK-registered doctors will go over your answers and prescribe semaglutide if it is safe and appropriate to do so. Your medication will then be sent to an address of your choice in discreet packaging.

Can you get semaglutide without a doctor?

To get semaglutide you will need a semaglutide prescription from a doctor. It cannot be bought over the counter at a pharmacy or supermarket and can only be prescribed to suitable patients who meet strict criteria.

You do not necessarily need to see a doctor face to face to get semaglutide, though. Services like ZAVA can prescribe semaglutide to suitable people using their online service.

Is semaglutide available on the NHS for weight loss?

Yes, semaglutide injections for weight loss are available on the NHS as a weight loss treatment option. You’ll need to be referred to a tier 3 weight management service to get Wegovy on the NHS. Some GPs can prescribe Wegovy but this isn’t yet a national standard.

An NHS doctor may recommend using semaglutide for weight loss if diet or exercise changes alone have not worked.

What are the alternatives to semaglutide?

Semaglutide is a safe and effective treatment for weight loss, but it isn’t right for everybody. It may not be medically appropriate for some people to take semaglutide, and for others, they may not find the medication to be effective. Fortunately, other medications that work in similar ways can help you lose weight.

Tirzepatide vs semaglutide

Mounjaro is currently the only other approved weight loss injection in the UK that’s available for prescription now. It contains tirzepatide, which also mimics GLP-1, as well as a second hormone called GIP. The hormones work together to enhance appetite suppression and feelings of fullness for longer after a meal. Like semaglutide, it’s taken once weekly as an injectable pen.

While semaglutide (Wegovy) can help you lose up to 15% of your starting weight at the maintenance dose after 68 weeks, tirzepatide (Mounjaro) has been shown to help people lose up to 22.5% of their starting weight after 72 weeks. Although Mounjaro has higher results, it was tested for 4 weeks longer, so we can’t say which is the most effective although they both have promising results.

Dulaglutide vs semaglutide

Dulaglutide is a similar medication to semaglutide and is in the same group of medications - a GLP-1 agonist. It is used as a treatment for type 2 diabetes under the name Trulicity and it is currently not available in the UK as a weight loss treatment.

Studies comparing the effectiveness of dulaglutide and semaglutide on weight loss show that semaglutide is a more effective option for most people.

Liraglutide vs semaglutide

Liraglutide is also a GLP-1 agonist and is available for weight loss as an injection under the name Saxenda. It works in the same way as semaglutide but is taken as a daily injection instead of a weekly one.

Patients taking semaglutide can expect to lose around 15% of their body weight, while those taking liraglutide can expect to lose around 8%. Saxenda is also long-term out of stock and we aren’t sure if or when it’ll become available again.

Conclusion: Is semaglutide a good drug for weight loss?

Clinical trials show that semaglutide delivers promising results for weight loss. After 68 weeks of using 2.4mg semaglutide injections, 86% of patients achieved at least 5% weight loss and almost 50% lost 15% or more of their weight in the same period.

Whether semaglutide is the right medicine for you will depend on a variety of factors, including whether you meet the criteria for treatment and are happy to commit to a diet and exercise plan alongside the medication.

Start a Request for Weight Loss Treatment With Free Medical Check-ins & Weight Loss Support

Frequently asked questions

Can you lose weight on semaglutide without changing your diet?

Semaglutide does not result in weight loss by itself. It is recommended that you follow a restricted-calorie diet and increase your exercise output while taking semaglutide to achieve the full benefits of the medication.

What happens if I miss a week of semaglutide?

If it has been more than 5 days since you should have used semaglutide, you will need to skip your missed dose. Then inject your next dose as usual on your next scheduled day. Never make up for a missed dose by taking a double dose.

If you miss your dose of semaglutide and it is within 5 days from your last dose, you should take it as soon as you remember. Then inject your next dose as usual.

Can semaglutide cause hair loss?

Hair loss is listed as a potential side effect of semaglutide, including Wegovy and Ozempic. Some people can experience temporary hair loss when they lose weight, but it usually only lasts for about 6 months. If you are concerned about hair loss and semaglutide, speak to your doctor.

How do you know if semaglutide is working?

It can take several weeks or months for you to notice any benefits for weight loss while using semaglutide. If you do not notice any effects or haven’t lost at least 5% of your starting weight after 6 months, you should consider discussing alternative weight loss interventions with your doctor. If you have diabetes, you may notice your blood sugar levels lowering after 2 weeks.

Can I take semaglutide if I am not diabetic?

Yes, semaglutide is effective for weight loss in diabetics and non-diabetics. Your doctor will confirm if you meet the criteria required for semaglutide treatment.

Medically reviewed by

brenda-ikeji.png Dr Brenda Ikeji

Brenda studied medicine at St Georges University of London and has most recently worked in John Radcliffe Oxford University Hospitals, covering acute and general medicine.

Last reviewed: 18 Sep 2024

Sources

Trusted by Thousands

Your Health Guided by Experts

Every consultation and treatment is overseen by our dedicated UK doctors, providing trusted care from start to finish. Meet the team behind your journey to better health.

Meet the Team
dr zenon andreou medical director
Dr Zenon Andreou

Medical Director

Dr Babak Ashrafi Clinical Lead for Service Development
Dr Babak Ashrafi

Clinical Lead for Service Expansion

dr kathryn basford online doctor
Dr Kathryn Basford

Online Doctor

Meet the Team