Discover how weight loss injections such as Wegovy® and Mounjaro® work, how they help reduce appetite, who they’re suitable for and what to expect from treatment.
How Do Weight Loss Injections Work?
Weight loss injections have become an increasingly popular treatment option for people looking to achieve and maintain a healthier weight. Prescription medications such as Wegovy® and Mounjaro® are designed to support weight loss by helping to reduce appetite, increase feelings of fullness and make it easier to eat smaller portions as part of a healthy lifestyle.
Unlike fad diets or quick-fix solutions, prescription weight loss injections are clinically approved medicines that are prescribed following a comprehensive health assessment. When used alongside a balanced diet, regular physical activity and ongoing clinical support, they can help suitable patients achieve sustainable, long-term weight loss.
In this guide, we’ll explain how weight loss injections work, the differences between Wegovy® and Mounjaro®, who may be suitable for treatment and what you can expect from our Weight Management Programme at PillBox Chemists.
What Are Weight Loss Injections?
Weight loss injections are prescription-only medicines designed to help suitable adults lose weight as part of a clinically supervised Weight Management Programme. They are not available over the counter and should only be used following a comprehensive health assessment by a qualified healthcare professional.
Medications such as Wegovy® (semaglutide) and Mounjaro® (tirzepatide) work by helping to regulate appetite and increase feelings of fullness, making it easier to reduce calorie intake and develop healthier eating habits.
It’s important to understand that weight loss injections are not a quick fix. They are most effective when used alongside a balanced diet, regular physical activity and long-term lifestyle changes. Combining medication with healthy habits and ongoing clinical support can help suitable patients achieve sustainable, long-term weight loss.
At PillBox Chemists, our Weight Management Programme includes a comprehensive health assessment, mandatory blood tests before treatment begins and regular clinical reviews to help ensure your treatment is safe, effective and tailored to your individual needs.
How Do Weight Loss Injections Work?
Weight loss injections work by mimicking the action of naturally occurring hormones in your body that help regulate appetite and food intake. These medicines act on areas of the brain that control hunger, helping you feel satisfied with smaller meals and reducing the urge to snack between meals.
One of the main hormones involved is called GLP-1 (Glucagon-Like Peptide-1). This hormone is naturally released after eating and sends signals to your brain to let you know when you’ve had enough to eat. Weight loss medications such as Wegovy® and Mounjaro® are designed to mimic this natural process, helping you manage your appetite more effectively.
Weight loss injections can help by:
- Reducing your appetite, so you feel less hungry throughout the day.
- Helping you feel fuller for longer, making it easier to eat smaller portions.
- Slowing the rate at which your stomach empties, helping you stay satisfied after meals.
- Reducing food cravings, particularly for high-calorie foods and snacks.
- Supporting better portion control, making it easier to maintain a calorie-controlled diet.
These medicines do not “burn fat” directly or increase your metabolism. Instead, they help you eat less by working with your body’s natural appetite-regulating hormones. When combined with a healthy diet, regular physical activity and ongoing clinical support, they can help suitable patients achieve sustainable, long-term weight loss.
How Does Wegovy® Work?
Wegovy® is a prescription-only weight loss medication that contains the active ingredient semaglutide. It belongs to a group of medicines known as GLP-1 receptor agonists, which mimic the action of the naturally occurring GLP-1 hormone involved in regulating appetite and food intake.
Wegovy® is administered as a once-weekly injection. By acting on areas of the brain that control hunger, it helps reduce appetite, increase feelings of fullness and make it easier to eat smaller portions. It also slows the rate at which the stomach empties, helping you feel satisfied for longer after meals.
Many patients find that Wegovy® helps them reduce snacking, manage food cravings and maintain healthier eating habits. However, it is most effective when used alongside a balanced diet, regular physical activity and ongoing clinical support as part of a comprehensive Weight Management Programme.
At PillBox Chemists, Wegovy® is prescribed only after a thorough health assessment and mandatory blood tests to ensure the treatment is appropriate and safe for your individual needs. Throughout your treatment, our clinical team will provide regular reviews and ongoing support to help you achieve sustainable, long-term weight loss.
How Does Mounjaro® Work?
Mounjaro® is a prescription-only weight loss medication that contains the active ingredient tirzepatide. Unlike Wegovy®, which targets a single hormone, Mounjaro® works by activating both the GIP (Glucose-Dependent Insulinotropic Polypeptide) and GLP-1 (Glucagon-Like Peptide-1) receptors. This is why it is known as a dual GIP and GLP-1 receptor agonist.
Mounjaro® is administered as a once-weekly injection and works by helping to regulate appetite, increase feelings of fullness and reduce hunger, making it easier to eat smaller portions and maintain healthier eating habits. It also slows the rate at which the stomach empties, helping you stay fuller for longer after meals.
As well as supporting weight loss, Mounjaro® may also help improve blood sugar regulation, although its suitability depends on your individual health needs and medical history.
At PillBox Chemists, Mounjaro® is prescribed only after a comprehensive health assessment and mandatory blood tests to ensure the treatment is safe and appropriate for you. Throughout your Weight Management Programme, you’ll receive regular clinical reviews and ongoing support to help you achieve sustainable, long-term weight loss.
Wegovy® vs Mounjaro®: What’s the Difference?
Both Wegovy® and Mounjaro® are once-weekly prescription weight loss injections that can help suitable patients lose weight by reducing appetite and increasing feelings of fullness. While they work in similar ways, there are some important differences.
| Feature | Wegovy® | Mounjaro® |
| Active ingredient | Semaglutide | Tirzepatide |
| Medicine type | GLP-1 receptor agonist | Dual GIP and GLP-1 receptor agonist |
| How it works | Mimics the GLP-1 hormone | Mimics both GIP and GLP-1 hormones |
| Administration | Once-weekly injection | Once-weekly injection |
| Appetite control | Helps reduce appetite and increase feelings of fullness | Helps reduce appetite, increase feelings of fullness and support appetite regulation |
| Blood sugar regulation | Supports blood sugar regulation through GLP-1 activity | May provide additional blood sugar regulation through both GIP and GLP-1 activity* |
| Prescribed after | Clinical assessment and mandatory blood tests | Clinical assessment and mandatory blood tests |
Both medications are prescribed as part of a clinically supervised Weight Management Programme and should be used alongside a balanced diet, regular physical activity and long-term lifestyle changes.
The most suitable treatment will depend on your medical history, Body Mass Index (BMI), health assessment, blood test results and individual treatment goals. During your consultation, our healthcare professionals will discuss your options and recommend the medication that is most appropriate for your needs.
*Blood sugar regulation varies between individuals and should not be the sole reason for choosing a treatment. Your healthcare professional will recommend the most appropriate option based on your clinical assessment.
What Results Can You Expect?
Everyone’s weight loss journey is different, and the results you achieve will depend on a range of factors, including your starting weight, lifestyle, medical history, adherence to treatment and how your body responds to the medication.
Weight loss injections are designed to support gradual, sustainable weight loss rather than provide an overnight solution. The best results are typically seen when treatment is combined with a balanced diet, regular physical activity and long-term healthy lifestyle changes.
To help minimise side effects and allow your body to adjust, your medication will usually be started at a lower dose and gradually increased over time, following your healthcare professional’s guidance.
At PillBox Chemists, your progress doesn’t stop once treatment begins. Our Weight Management Programme includes regular clinical reviews to monitor your progress, assess how you’re responding to treatment and make any necessary adjustments to help you achieve the best possible outcome safely.
It’s important to remember that successful weight management is about building healthier habits for the long term. Your healthcare team will work with you throughout your journey, providing ongoing support, advice and encouragement every step of the way.
Are Weight Loss Injections Safe?
When prescribed appropriately and used under the supervision of qualified healthcare professionals, weight loss injections such as Wegovy® and Mounjaro® are considered safe and effective for many suitable patients.
These medications are prescription-only medicines and should never be started without a comprehensive clinical assessment. Before treatment begins, our healthcare professionals will review your medical history, current medications and lifestyle to determine whether weight loss treatment is appropriate for you.
At PillBox Chemists, every patient is required to undergo mandatory blood tests before starting treatment. These blood tests help assess your overall health and identify any underlying conditions that may affect your suitability for treatment or require further medical investigation.
Once treatment has started, you’ll receive regular clinical reviews and ongoing monitoring to assess your progress, manage any side effects and adjust your treatment plan where appropriate. This ensures your Weight Management Programme remains safe, effective and tailored to your individual needs.
Like all prescription medicines, Wegovy® and Mounjaro® can cause side effects. The most common include nausea, vomiting, diarrhoea, constipation and abdominal discomfort. These side effects are usually mild and often improve as your body adjusts to the medication, particularly when the dose is increased gradually.
If you experience severe or persistent side effects, it’s important to seek medical advice promptly. Our healthcare team is available to provide ongoing support throughout your treatment and answer any questions you may have.
Who Might Be Suitable for Weight Loss Injections?
Weight loss injections may be suitable for adults who are living with overweight or obesity and have been unable to achieve their weight loss goals through diet and exercise alone. However, treatment is not suitable for everyone and should only be prescribed following a comprehensive clinical assessment.
When considering whether weight loss treatment is appropriate, our healthcare professionals will take into account a number of factors, including:
- Your Body Mass Index (BMI) and whether you meet the eligibility criteria.
- Your medical history, including any existing health conditions or previous treatments.
- Your current medications, to ensure treatment is safe and appropriate.
- Your health assessment, including your weight loss goals and overall wellbeing.
- Mandatory blood tests, which help assess your general health and identify any underlying conditions before treatment begins.
The decision to prescribe Wegovy® or Mounjaro® is based on your individual circumstances rather than a single measurement. Our healthcare professionals will recommend the most appropriate treatment after reviewing your assessment results and discussing your health goals. Not sure if you’re eligible? Use our BMI Calculator to calculate your Body Mass Index (BMI) and get a better understanding of whether you may be suitable for our Weight Management Programme. Your BMI is an important starting point, but your overall health will always be considered before any treatment is prescribed.
What Are the Common Side Effects of Weight Loss Injections?
Like all prescription medicines, Wegovy® and Mounjaro® can cause side effects. However, not everyone experiences them, and for many people, they are mild and temporary.
The most commonly reported side effects include:
- Nausea
- Constipation
- Diarrhoea
- Vomiting
- Reduced appetite
- Abdominal discomfort or stomach pain
- Indigestion or bloating
These side effects are often most noticeable when treatment first begins or after your dose has been increased. In many cases, they improve as your body gradually adjusts to the medication.
To help reduce the risk of side effects, treatment is usually started at a lower dose and gradually increased over time. Eating smaller meals, staying well hydrated and following the advice provided by your healthcare professional may also help improve your comfort during treatment.
If you experience severe, persistent or concerning side effects, it’s important to contact your healthcare professional promptly. At PillBox Chemists, our clinical team provides ongoing support throughout your Weight Management Programme and is available to answer your questions or discuss any concerns you may have during treatment.
How PillBox Chemists Can Help
At PillBox Chemists, we believe that successful weight management is about more than simply prescribing medication. Our clinically supervised Weight Management Programme is designed to provide personalised care, ongoing support and regular monitoring throughout your treatment journey.
When you choose PillBox Chemists, you can expect:
- A comprehensive consultation with one of our qualified healthcare professionals to assess your suitability for treatment.
- Mandatory blood tests before treatment begins to help assess your overall health and ensure treatment is safe and appropriate.
- Access to Wegovy® or Mounjaro®, where clinically appropriate following a full assessment.
- Regular clinical reviews to monitor your progress and support your weight loss journey.
- Ongoing monitoring and personalised support, with treatment adjusted where necessary to help you achieve the best possible outcome safely.
- Advice on healthy eating, physical activity and long-term lifestyle changes to help you maintain your results beyond medication.
Our team is committed to providing safe, evidence-based care tailored to your individual needs. From your initial consultation through to your regular follow-up appointments, we’ll work with you every step of the way to help you achieve sustainable, long-term weight loss.
Ready to take the next step? Book a consultation with PillBox Chemists today to find out whether our Weight Management Programme is right for you.
Frequently Asked Questions
How do weight loss injections work?
Weight loss injections such as Wegovy® and Mounjaro® work by mimicking naturally occurring hormones that help regulate appetite. They help you feel fuller for longer, reduce hunger and make it easier to eat smaller portions as part of a healthy lifestyle.
How long do weight loss injections take to work?
Everyone responds differently. Some people notice changes in their appetite within the first few weeks, while weight loss generally occurs gradually over time. The best results are achieved when treatment is combined with healthy eating, regular physical activity and ongoing clinical support.
Do weight loss injections burn fat?
No. Weight loss injections do not directly burn fat or speed up your metabolism. Instead, they help reduce appetite and support healthier eating habits, making it easier to consume fewer calories and lose weight over time.
Do weight loss injections reduce appetite?
Yes. Both Wegovy® and Mounjaro® help regulate appetite by acting on hormones involved in hunger and fullness, helping many people feel satisfied with smaller meals and reducing food cravings.
Can I stop taking weight loss injections?
You should always speak to your healthcare professional before stopping treatment. They can advise you on the most appropriate next steps and help you develop a long-term plan to support maintaining your weight loss.
Are weight loss injections safe?
When prescribed following a comprehensive clinical assessment and used under the supervision of qualified healthcare professionals, Wegovy® and Mounjaro® are considered safe and effective for many suitable patients. Like all medicines, they can cause side effects, so regular monitoring is important.
What’s the difference between Wegovy® and Mounjaro®?
Both are once-weekly prescription weight loss injections, but they contain different active ingredients. Wegovy® contains semaglutide and targets the GLP-1 receptor, while Mounjaro® contains tirzepatide and targets both the GIP and GLP-1 receptors. Your healthcare professional will recommend the most appropriate treatment based on your individual needs.
Do I need blood tests before starting treatment?
Yes. At PillBox Chemists, mandatory blood tests are required before treatment begins. These help assess your overall health and ensure that treatment is safe and appropriate for you.
Do I need to inject every day?
No. Both Wegovy® and Mounjaro® are administered as once-weekly injections, making them convenient to incorporate into your routine.
Are weight loss injections available on the NHS?
Some weight loss medications may be available through the NHS for patients who meet specific eligibility criteria. However, availability varies depending on local NHS services. At PillBox Chemists, we offer a private Weight Management Programme for suitable patients following a comprehensive clinical assessment.
Can I exercise while taking weight loss injections?
Yes. Regular physical activity is encouraged alongside treatment. Combining weight loss medication with a balanced diet and exercise can help improve your overall health and support sustainable weight loss.
What happens if I miss a dose?
If you miss a dose, follow the instructions provided with your medication or speak to your healthcare professional or pharmacist for advice. Do not take an extra dose to make up for a missed injection unless you have been advised to do so.
Will I regain weight if I stop taking weight loss injections?
Weight management is a long-term journey. Some people may regain weight after stopping treatment, particularly if healthy eating habits and regular physical activity are not maintained. Your healthcare professional will work with you to develop a personalised plan to help support your long-term weight management goals.
Ready to Take the Next Step?
If you’re considering prescription weight loss treatment, the first step is a comprehensive clinical assessment to determine whether it’s the right option for you.
At PillBox Chemists, our Weight Management Programme is designed to provide safe, personalised and clinically supervised care from start to finish. Every patient receives a thorough consultation, mandatory blood tests before treatment begins and ongoing clinical reviews throughout their weight loss journey.
Whether Wegovy® or Mounjaro® may be suitable for you will depend on your individual health needs, medical history and assessment results. Our experienced healthcare professionals will guide you through every stage of the process and recommend the most appropriate treatment for your circumstances.
Book your consultation today to find out whether our Weight Management Programme could help you achieve your long-term weight management goals safely and confidently.
Start Your Weight Management Assessment
Ready to find out whether Wegovy® or Mounjaro® may be suitable for you?
Complete our online Weight Management Assessment and our clinical team will review your information before contacting you with the next steps.
✔ Comprehensive health questionnaire
✔ Reviewed by our healthcare professionals
✔ Helps determine your suitability for treatment
✔ Mandatory blood tests required before treatment begins
👉🏼 Start Your Weight Management Assessment
*Completing the assessment does not commit you to treatment. It simply allows our clinical team to review your information and determine whether our Weight Management Programme may be suitable for you.
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