Weight-loss injections, such as Wegovy, are available to some people on the NHS, and can be bought via private prescription too - if you meet certain criteria.
Despite the hype, it's important to remember there is no such thing as a magic bullet for weight loss - jabs won't be suitable for everyone and all treatments have their pros and cons.
In this guide we outline what you need to know about weight-loss drugs, how they work, where you can access them and what to be aware of.
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How do weight-loss jabs work?
Weight-loss jabs such as Wegovy and Mounjaro work by mimicking hormones in your body that send signals to the part of your brain responsible for appetite and hunger.
Known collectively as GLP-1 receptor agonists, they slow digestion and increase the time it takes for food to leave your stomach, alter brain signals to help you feel fuller for longer, reduce appetite and increase insulin to regulate blood glucose levels.
The drugs come in a pre-measured dose in a single-use auto-injector pen, which is administered as a weekly injection in your upper arm, stomach or thigh.
People taking Wegovy or Mounjaro typically start to lose weight within two to four weeks of starting the drug.
In trials, weight-loss drugs have helped people lose up to 22% of their body weight and, as a result, reduce their risk of weight-related co-morbidities, including diabetes, high blood pressure, several cancers and cardiovascular disease.
There's also evidence that these drugs, independent of weight loss, reduce the risk of heart attacks and strokes, and reduce cravings for high-fat, high-sugar foods and alcohol.
Patients usually start on a low dose and stay on this for four weeks to allow their bodies to adapt and get used to any side effects.
After this the dose generally increases every four weeks up to the maximum dose - although you can stay on a lower dose for longer if you're happy with your weight loss or are experiencing side effects.
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Ozempic vs Wegovy vs Mounjaro: what's the difference?
Although Ozempic is the most widely recognised name, it's not authorised as a weight-loss drug. Ozempic is the brand name for the drug semaglutide and is used to treat type 2 diabetes.
Ozempic isn't registered for and shouldn't be used for weight loss as the doses can be different.
The weight-loss drugs currently approved for use in the UK are Wegovy and Mounjaro.
Wegovy (which, like Ozempic, contains semaglutide) targets one receptor in the body whereas Mounjaro (tirzepatide) targets two receptors and has been shown in trials to lead to greater weight loss.
You might also have heard of Saxenda, which works in a similar way - using the active ingredient liraglutide - but requires daily rather than weekly injections.
This drug has been around for longer and is also available via private prescription or the NHS weight management service.
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Can I get weight-loss jabs on the NHS?
Some people are eligible for weight-loss jabs via the NHS. At the moment, the drug available is Wegovy.
To qualify, patients must meet certain guidelines set by the National Institute for Health and Care Excellence (NICE).
However not everyone in the UK who is eligible has been able to access the jabs. There have been issues with the supply chain and Wegovy can currently only be prescribed on the NHS via specialist weight management services (SWMS).
NHS eligibility criteria
Adults must have at least one pre-existing, weight-related health condition such as high blood pressure, cardiovascular disease or osteoarthritis and:
- a Body Mass Index (BMI) of 35kg/m2 or more, OR
- a BMI of 30kg/m2 or more and qualify for referral to a SWMS and have unsuccessfully tried to lose weight through other methods.
People from certain ethnic minority backgrounds, including Black, Asian, Chinese and Middle Eastern, are eligible at a lower BMI threshold of 27.5kg/m2 because their risk of disease increases at a lower BMI.
In July 2024, Wegovy was also approved for use in patients with cardiovascular disease with a BMI of 27kg/m2 or more to reduce the risk of heart attacks and strokes.
Under current guidelines, Wegovy should be prescribed at the same time as a reduced-calorie diet and physical exercise and can only be prescribed for a maximum of two years.
GPs can't currently prescribe it so you'll need to be referred by your GP to a specialist weight management service (SWMS).
Mounjaro, another weight-loss jab approved for use in the UK, isn't currently available on the NHS but many expect it will be soon.
If you get a NHS prescription for Wegovy you'll pay the cost of a standard prescription, currently £9.65 per item, unless you qualify for free prescriptions.
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Can I buy weight-loss jabs privately and how much do they cost?
Yes, both Wegovy and Mounjaro are available to buy through private prescription in the UK, but they don't come cheap. All the major high street pharmacy chains sell them, as well as specialist online pharmacies.
The starting dose of Wegovy (0.25mg) starts from around £130 a month. The cost rises when the dose increases (roughly every four weeks up to a maximum level). The maximum dose (2.4mg) costs upwards of £269 a month.
The costs for Mounjaro are similar, starting from £130 a month for the lowest dose (2.5mg), up to £180+ a month for the highest dose (15mg).
Eligibility criteria for private prescriptions
To get a private prescription, patients need to complete an online form with questions about their weight, medical history and any current medications. Some pharmacies also require you to send in photo evidence.
There are still eligibility criteria to meet but these are less limited than NHS ones.
Patients must have a BMI of 30kg/m2 or more, or 27kg/m2 or more and a weight-related medical condition.
A doctor should review your medical form, and if you're approved for treatment, you can either collect the drugs or they're sent to you in the post.
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What to know about weight-loss injections
While these drugs can lead to dramatic weight loss, there are some important things to consider.
The weight-loss effects will only last as long as you're taking the drugs. Once you stop, your appetite will return to normal and you'll regain at least some of the weight lost.
Under current NICE guidelines, Wegovy can only be prescribed on the NHS for a maximum of two years. There's no limit for patients accessing these drugs with private prescriptions, but it is a significant ongoing cost, and the long-term effects are still being studied.
It's also important to have diet and exercise support while taking them for maximum benefit - and to ensure you are still getting the essential nutrition you need.
People accessing Wegovy via the NHS weight management service are supported with advice on diet and exercise, but this doesn't always happen for those on private prescriptions (although it is meant to be provided).
Giles Yeo, Professor of Molecular Neuroendocrinology at the MRC Metabolic Diseases Unit, University of Cambridge, thinks this is concerning. He says: 'These drugs shouldn’t be used in isolation. When people drastically reduce their dietary intake, as they do on these drugs, there is a risk of fibre, protein and micronutrient deficiencies.’
He thinks it’s essential people are supported with nutrition and physical exercise advice: ‘When you lose weight quickly you lose 50% fat and 50% muscle mass. No one signs up to lose muscle and people need to offset this with exercise and resistance training, especially those over 40’.
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Possible side effects of weight-loss injections
Wegovy and Mounjaro can have unpleasant side effects, the most common being nausea and vomiting, heartburn, constipation, diarrhoea, stomach pains and headaches, which affect around 10% of people taking them.
More severe, but rarer side effects reported have included pancreatitis, kidney problems and thyroid tumours. If you have retinopathy - a diabetic eye disease - and use insulin, using Wegovy can make your vision worse.
Other medications can interact with weight-loss drugs, and they aren't suitable for everyone, so check with your health provider first.
It's important to remember that these drugs need to be used with caution and according to the guidelines. See our full weight-loss jabs investigation for more on the issues with people taking them who don't need them.
Where to buy weight-loss jabs
There are numerous online pharmacies offering private prescriptions for Wegovy and Mounjaro and prices vary. It's important to be careful about where you buy from and only use legitimate providers.
It's not worth risking your health by buying from unauthorised sources. You may end up with fake products that could be harmful or not have the appropriate checks to make sure they're safe for you.
Big-brand pharmacies who sell weight-loss jabs include:
- Asda Online Doctor
- Boots
- Lloyds
- Superdrug
- Well
There are a range of smaller and online-only pharmacies too, but make sure you double check any pharmacy you wish to use is licensed and legitimate.
Use the General Pharmaceutical Council (GPhC) guide to checking a pharmacy is registered and safe. Always check for a registered pharmacy logo and check the registration number shown on the GPhC website. You can also check Trustpilot to sense-check other customers' experiences.
Check if the service offers free ongoing support, such as access to a GP, and useful extras like free injector pen bins/collection (more on this below).
For more advice, check the Medicines and Healthcare Regulatory Authority (MHRA) guidance for accessing Wegovy and other weight-loss drugs.
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What to do with used Wegovy or Ozempic pens
Because Wegovy, Mounjaro and Ozempic pens all contain needles they are considered clinical waste and should be disposed of in a safe way, ideally in a Sharps bins or container.
You can get these from your pharmacy or online. Some services provide these as standard.
Once the bin is full you can return it via the service you are using, or ask your community pharmacy if they will accept the bin. Some councils also offer a collection service for clinical waste.
The amount of pens being used as these products become more widespread creates a massive amount of plastic waste.
Novo Nordisk, the brand that makes the pens, has now started a recycling scheme called Pencycle.
You can pick up a box from your local participating pharmacy, or order it online, fill it with pens (it holds 12) and drop it off or post it free of charge when full. Find out more on the Pencycle minisite.
Other weight-loss medications
Another weight-loss medication available on prescription is Orlistat, also known by the brand names Xenical or Alli.
Orlistat is a pill that is taken at the same time as a meal and reduces the amount of fat your body absorbs from your meal by around 30%. Instead it excretes it as waste.
There are criteria to meet before patients can be prescribed Orlistat, either on the NHS or privately, and these include a BMI of 28kg/m2 or more and a weight-related medical comorbidity, or a BMI of 30kg/m2 or more.
If you get Orlistat via a private prescription from an online pharmacy, a monthly dose will cost around £58.
Orlistat isn't suitable for everyone. It interacts with certain medications such as certain blood thinners and treatment for rheumatoid arthritis so it's important to check with a doctor before using it.
There are also some unpleasant side effects associated with it including bloating, headaches and an oily discharge from your bottom.
Be wary of weight-loss ads on social media
Weight loss is big business, and where there is high demand, there are scammers lurking.
Exercise extreme caution with weight-loss products you see advertised online and on social media. If it looks too good to be true, it probably is, and in the past, we've founddodgy and fake products onlineandfake celebrity diet pill endorsements.
It's not worth risking your health or your money.
