For many people, losing weight feels like an uphill battle. Research suggests that around 40% of Britons actively engage in weight management through diet and exercise, but for some even the most consistent efforts don’t produce results.
A range of factors influence your ability to lose weight, including genetics, hormonal imbalances, health conditions and certain medications. In some cases this means that adhering to a healthy diet and regularly exercising isn’t enough to create change. Instead, extra support may be required with the use of weight loss treatments.
Here, we discuss weight loss injectables - in particular Wegovy and Mounjaro - and how they work. We also explore their benefits and side effects to help you gain a deeper understanding of whether they might be the right treatment for you.
What are weight loss injectables?
Weight loss injectables are prescription medications that are designed to facilitate weight loss. They are administered as an injection, usually by the patient themselves, from a pen with pre-filled doses. Wegovy and Mounjaro are two brands of injectable medication that are available in the UK, and both contain a distinct active ingredient that makes it easier to lose weight with the help of a calorie-restricted diet and regular exercise.
How do Wegovy injectables work?
The Wegovy injection contains an active ingredient called semaglutide. This mimics the action of a hormone in your gut called GLP-1. This is released after eating and slows down the rate of digestion. It increases feelings of fullness and reduces the preference for high-fat foods. It also helps users to feel satisfied after smaller meals and consume fewer calories, resulting in steady and safe weight loss.
Wegovy also promotes the release of insulin when blood sugar levels are high, assisting with the regulation of blood glucose and the management of type 2 diabetes. Another brand name for semaglutide is Ozempic.
How do Mounjaro injectables work?
The Mounjaro weight loss injection contains the active ingredient tirzepatide. Like semaglutide, it stimulates feelings of fullness by activating receptors in the stomach and brain. In addition to mimicking GLP-1, tirzepatide influences a hormone called GIP, increasing the insulin sensitivity of cells in the fat tissue, muscle tissue and liver. This helps to regulate blood sugar and reduce carb cravings.
Who can use weight loss injectables?
Wegovy and Mounjaro can be prescribed privately for weight loss if patients meet certain criteria;
● Is aged 18 or over.
● Have a BMI of over 30 or have a BMI of over 27 and at least one weight-related health issue such as high blood pressure, or high cholesterol .
● It is also important to exclude pre existing medical conditions and ensure current medication does not interact with these medicines.
Those from some backgrounds such as Asian, Chinese, Middle Eastern, Black African or African-Caribbean may qualify for Wegovy and Mounjaro with a slightly lower BMI.
How to take weight loss injectables
Wegovy and Mounjaro are both administered as a once-weekly injection. They can be injected into the upper arm, thigh or abdomen.
The Wegovy injection comes in doses of 0.25mg, 0.5mg, 1mg, 1.7mg and 2.4mg. Mounjaro, meanwhile, comes in doses of 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.
With both injections, all patients start on the minimum dose and take it once a week for four weeks. The dose is then gradually increased over four-week periods until you reach your maintenance dose providing the clinician feels it is safe and appropriate to do so.
How much weight could you lose?
People taking weight reduction injections typically start to lose weight within a few weeks. However, they are designed to facilitate steady and consistent weight loss over many weeks and months - often treatment lasts one to two years. It’s also important to note that weight loss injectables should be used alongside a programme of healthy eating and exercise. How much weight you lose with the help of an injectable will depend on your dosage, your lifestyle choices and other factors such as any other medications you may be taking.
In one major study, people taking the maximum dose of Wegovy lost 12% of their body weight compared to those taking a placebo.[1] Both groups received advice and support from healthcare professionals during the trial. Another study found that participants taking semaglutide (the active ingredient in Wegovy) once a week for 68 weeks lost an average of 14.9% of their body weight.[2]
Research into the efficacy of the Mounjaro weight loss injection showed that when used over periods of 40 to 52 weeks, weight loss ranged from 5.5kg to 11.4kg in adults using 5-15mg doses.[3] Another study, conducted in 2022, showed that participants lost up to 20.9% of their starting body weight over a period of 72 weeks.[4]
Are weight reduction injections available on the NHS and privately?
Both Wegovy and Mounjaro are available to patients on the NHS, but they must be prescribed by a weight management specialist and access to these is restricted. It’s estimated that around 4.1 million Britons are eligible for Wegovy, while some 3.4 million people in the UK could eventually qualify for Mounjaro, which has only recently become available.[5] However, roll-out of Mounjaro is relatively slow, with NICE estimating that full access could take 10 years.
As such, some people may choose to access Wegovy or Mounjaro privately. These injectables should always be purchased from a reputable pharmacy following a consultation. At The Happy Pharmacy, our licensed UK clinicians can help you to access weight loss injectables with a simple, secure online consultation. Our prices for both medications start from £124.99.
Benefits of weight loss injectables
In addition to easier weight loss and weight management, using weight loss injectables can have other benefits. Both Wegovy and Mounjaro help to control blood sugar levels, and in 2024 the US Food and Drug Administration (FDA) announced that Wegovy could help to reduce the risk of heart attacks and strokes in adults with cardiovascular diseases.[6]
Mounjaro, meanwhile, can have an indirect impact on users’ blood pressure and LDL ‘bad’ cholesterol, helping people to lower both by losing weight.
Side effects of weight reduction injections
The most common side effects of weight loss injectables include nausea, diarrhoea, vomiting and constipation. The severity of these symptoms are usually mild and gradually subside over a few weeks.
In rare cases, more serious issues can develop. These include liver dysfunction, pancreatitis, and gallbladder or kidney problems. It’s therefore essential to only take the recommended dose and to use these medications under the supervision of a GP or clinician.
What happens when you stop taking weight loss medication?
While weight loss injections are considered an effective way to facilitate weight loss, becoming dependent on them carries health risks. They are designed to be used alongside a calorie-restricted diet and exercise, enabling you to make lifestyle adjustments that will help you to maintain a lower weight.
Research suggests that most people do regain at least some of the weight they have lost once they stop taking Wegovy or Mounjaro. The best way to maintain a healthy weight is therefore to create good habits - such as exercising regularly and eating a balanced diet that is low in fat and sugar. These habits should then be maintained after stopping the medication.
Weight loss injectables from The Happy Pharmacy
Here at The Happy Pharmacy, our aim is to make healthcare accessible, personalised and discreet. Our licensed clinicians provide high-quality medications as well as support to help you achieve and maintain a healthy weight.
If you would like to try Wegovy or Mounjaro, you can get started with our secure online consultation. This will be reviewed by our team and, if we think the medication is a safe and suitable option for you, we will deliver it in unbranded, secure packaging - straight to your doorstep. We also offer ongoing advice such as optional check-ins, dosage adjustments and lifestyle guidance to help you get the most from your weight loss journey.
FAQs about weight loss injectables
Can I use weight loss injections if I’m not diabetic?
While some injectables, such as Ozempic, are intended to treat type 2 diabetes, Wegovy and Mounjaro are designed to help those struggling to manage their weight. You can therefore use them if you do not have type 2 diabetes. However, you must fit the health and BMI criteria.
How long can I stay on weight loss injectables?
The National Institute for Health and Care Excellence (NICE) recommends that injectables such as Wegovy and Mounjaro are not used for more than two years.
How should I store my pens?
New, unused Wegovy and Mounjaro pens should be stored in the fridge at 2-8°C. Once opened they can be stored at room temperature, out of direct sunlight. All doses in the pen must be used within 30 days.
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