What are Weight-Loss Injections?

Weight loss injections are injectable medications used to tackle obesity. These are usually prescribed alongside a specific diet and exercise regime to help patients along their weight loss journey.

When used correctly, and in line with your prescriber's instructions, the injections prove a valuable asset when it comes to weight loss. When compared to oral medicines, injectables bypass the digestive system therefore a higher amount of the drug is available to exert its effect.

Tablets generally need to be taken more frequently, as is the case with semaglutide. Rybelsus is the only brand available as an oral tablet, and Ozempic, Wegovy and Mounjaro are all injectable brands. Rybelsus must be taken once daily as opposed to the injectables which only need to be used once weekly.

As they pass through your digestive system, tablets carry a higher risk of side effects compared to injections. Whilst there is limited research comparing the two forms, they are both effective treatments and patient preference is generally the deciding factor.

When compared to supplements, traditional medicines undergo extensive clinical trials and research into their effectiveness and safety. Manufacturers of supplements rarely carry out any clinical trials and therefore there is not much evidence to support whether or not they work.

Ozempic and Rybelsus are not licensed for weight loss treatment in the UK and have stopped being prescribed off-label for weight loss. These medicines can only be accessed through a prescriber for the treatment of diabetes.

How Do Weight-Loss Injections Work?

Semaglutide is known as a GLP-1 agonist. GLP-1 is a natural hormone released after you have eaten and sends signals to the brain which slows down the emptying of the stomach. As food therefore remains in the stomach for longer, you will feel fuller for longer.

Liraglutide is also a GLP-1 agonist but works to a varying degree compared to semaglutide. It degrades in the body much quicker and therefore Saxenda must be injected once daily, as opposed to Wegovy which is injected once weekly. Clinical trials have shown liraglutide as being less effective at promoting weight loss, compared to semaglutide.

Tirzepatide is a newer drug which does everything that both semaglutide and liraglutide do, in that it makes you feel fuller, and quicker for longer. Additionally, it will help to regulate your blood sugar levels by increasing insulin sensitivity. It does this by activating the GLP-1 pathway but also the GIP pathway.

With all these treatments, the role of diet and exercise cannot be understated. The manufacturers of these drugs all recommend a reduced-calorie diet alongside an increase in physical activity.

Top Weight-Loss Injections in the UK

Mounjaro (Tirzepatide)

Tirzepatide or Mounjaro is the most recent weight loss medication available on the UK market. It works by activating two pathways which simultaneously make you feel fuller and quicker for longer but also increases insulin sensitivity, improving blood sugar levels.

Mounjaro can help patients lose weight where other treatments have failed but it is important to incorporate lifestyle changes. A reduced-calorie diet, avoiding carbohydrates and high-fat foods, and an exercise plan are crucial to successful treatment.

Mounjaro has been compared against Wegovy 1mg in the SURPASS-2 clinical trial at doses of 5mg, 10mg and 15mg. Results show that over a 40 week period, up to 5.5kg more was lost in patients taking Mounjaro.

Mounjaro is injected subcutaneously once weekly, starting at 2.5mg for 4 weeks. After this, the dose can be increased and then maintained at 5mg. The dose can be increased further but only if additional control is needed.

Wegovy (Semaglutide)

Wegovy, containing the active ingredient semaglutide, works by making you feel fuller for longer. When used alongside a low-carb diet and an exercise plan, it has proven its role as an effective treatment for weight loss.

A clinical trial has assessed the effectiveness of Wegovy. Over a period of 68 weeks, 1961 patients were administered either 2.4mg semaglutide or placebo. A 15% reduction in body weight was observed in patients taking the drug compared to only 2% in those patients taking the placebo.

Wegovy, as with Mounjaro, is injected subcutaneously once a week. The starting dose is 0.25mg once weekly for 4 weeks. Every four weeks the dose is increased through 0.5mg, 1mg and 1.7mg. Patients can then maintain at 1.7mg or increase further if needed up to 2.4mg.

Saxenda (Liraglutide)

Saxenda contains the active ingredient liraglutide and is similar to semaglutide in that it is a GLP-1 agonist and works in the same way. The main difference is that it has a much shorter half-life. This means it does not last in your body for as long as semaglutide does. Due to this, Saxenda is administered once daily as opposed to weekly.

Two studies%20greater%20weight%20loss) evaluating the effectiveness of liraglutide in 3,000 obese participants found people lost 4-6kg more compared to participants who only made lifestyle changes.

The dosing schedule for liraglutide starts off at 0.6mg once daily for 1 week. After this, the dose increases every week through 1.2mg, 1.8mg, and 2.4mg until a maintenance dose of 3mg is reached.

Making the Right Choice: Factors to Consider

With so many options available, it can be challenging to decide which is the right treatment for you. All current weight loss medicines are effective at helping patients achieve a healthy weight so which one should you go for?

When considering treatment, it is important to take into account your individual circumstances. Consider the following:

  • Are you taking any other medication?

  • Do you suffer from other medical conditions?

  • Do you suffer from allergies?

  • How do you react to medicine?

  • Regarding injections - are you confident at injecting?

  • What is your current schedule? - can you fit the dosage regime around your schedule? Most patients prefer a weekly dose to a daily one.

The answer to all these can help you decide which of the weight loss treatments are best based on your individual preferences and circumstances. There is no one-size-fits-all approach to weight loss injections. For some individuals, you may need to trial the injection and settle on the one that is most effective with little to no side effects.

Other factors that you should consider are your weight loss goals and whether you have any weight-related medical problems. Do you need to lose weight as quickly and safely as possible? Or are you nearing your ideal body weight and just need something to lose the last few stubborn pounds?

Who Can Benefit from Weight-Loss Injections?

As weight loss medicines can lead to adverse events if not used correctly, they would only be prescribed for patients for whom the medication would be safe and appropriate.

Individuals with a BMI of 30 and above are considered obese and qualify for treatment. Individuals with a lower BMI may also benefit from treatment if they also have a weight-related health condition such as high blood pressure or type 2 diabetes.

It is important to note that BMI on its own is not accurate for everyone. Individuals with low body fat but high muscle mass may also present with an obese BMI. In all cases, it is important to consult with a healthcare professional who is optimally placed to provide treatment-specific recommendations. A prescriber can also offer opportunistic advice to ensure successful treatment.

How to Get Weight-Loss Injections in the UK?

All weight loss injections are prescription-only medications. This means a prescriber must be involved in the consultation process who will then determine suitability and prescribe the treatment for you.

When requesting treatment from an online doctor or pharmacy like Quick Meds, this usually begins with an online consultation form. This encompasses personal information such as date of birth and gender but also information about your past and current health.

Following the form and checkout, you will be invited for a telephone consultation to confirm all information provided. This is when the prescriber will provide invaluable advice both about the treatment and the condition they intend to treat.

The prescriber will also provide lifestyle advice specific to the treatment being prescribed to help you maximize treatment potential.

Here at Quick Meds, we work closely with manufacturers and wholesalers to ensure a regular supply of all medicine for all our patients' needs. Currently, all preparations, Wegovy and Mounjaro, exist as a single pre-filled pen containing multiple doses. Saxenda also exists as a pre-filled pen but as a multi-pack, due to the dose titration required at onset of treatment.

Potential Side Effects and Precautions

All current weight loss injections are GLP-1 agonists, including Mounjaro which is additionally a GIP agonist. As they all work through the same mechanism, though to varying degrees, they all have a similar side effect profile.

The most common side effects seen with these medicines are nausea, vomiting and diarrhoea. Loss of appetite is also common, but this is one of the ways how the medicine works to keep you feeling fuller for longer.

Nausea, vomiting and diarrhoea can cause dehydration which may lead to kidney disease, so it is important to ensure you maintain an adequate fluid intake whilst on treatment.

Rare but serious side effects associated with all weight loss injections are:

  • Pancreatitis - inflammation of the pancreas, which if suspected, warrants discontinuation of treatment which cannot be restarted. Signs include severe stomach pain that spreads to the back or chest, accompanied by fever, nausea or vomiting.

  • Gallstones - characterised by severe stomach discomfort and pain which increases rapidly, and yellowing of the skin or eyes.

  • The patient information leaflet contains a comprehensive list of side effects. Your healthcare provider can also offer treatment advice if you currently suffer from another medical condition.

Women of childbearing potential are advised to use contraception whilst on treatment with a weight loss injection as all these medicines have the potential to harm an unborn baby.

Additionally, patients considering Mounjaro who are currently using an oral contraceptive pill must also use an additional method, such as a barrier method, as tirzepatide may reduce the effectiveness of the oral contraceptive pill for the first 4 weeks after initiation and after each dose increase.

If you suffer from other medical conditions, including other weight-related conditions or long-term health problems such as diabetes or severe heart failure, ensure you speak to your prescriber for advice to help you lose weight safely with the most appropriate medication.

Tips for Successful Weight Loss with Injections

It is important to ensure you make lifestyle changes whilst on weight loss treatment. The body adjusts to weight loss when you omit fast food, eat less food high in carbohydrates and incorporate healthy eating habits. This can help you lose weight and prevent weight regain after treatment has been stopped.

Exercising for 30 minutes at least 5 days a week assists the medication in helping you achieve your goal weight. Even without medication, making lifestyle changes to create a calorie deficit is the basic formula to help you lose weight.

Alongside treatment, it is important to regularly weigh yourself to monitor your progress. Steady progress may not be immediately visible so regular weighing can help keep you motivated by monitoring your success.

Setting realistic goals and staying motivated are effective ways to help along your journey to losing weight. Setting a goal weight loss of 5% of your starting weight or aiming to lose 1-2 lbs per week is considered safe and sustainable in the long term.

Summary

In conclusion, weight loss injections offer patients an effective way to tackle their weight gain. When used in line with a prescriber's guidance, patients can achieve healthy weight loss by shedding excess weight steadily and safely.

Whilst there are currently a few different options on the market, they all work predominantly the same way. Which weight loss injection is right for you depends on your individual circumstances, including your past or current medical history. Importantly, healthy changes to a patient's lifestyle must be implemented to see added benefit.

It is important to consult with a healthcare professional when considering obesity medication as these are classed as prescription-only medicine. A prescriber is optimally placed to advise on how best to use the medication as well as advise on some very common side effects.

FAQs

How much weight can I expect to lose with these injections?

How much weight you lose on treatment is patient-specific. This depends on your initial body weight at the start of treatment and how strictly you have implemented lifestyle changes.

Are weight-loss injections safe for long-term use?

There is limited data to indicate whether weight loss injections are safe for long-term use. Obesity is a chronic disease that requires long-term management. Long-term risks have not currently been evaluated, and as with all other medications, the benefits of treatment must outweigh any associated risks.

Can I stop taking the injections once I reach my desired wei

You can stop taking the injections after you have reached your goal weight but many patients do regain the lost weight. It is important to use weight loss pens as an aid in incorporating healthy eating habits and regular exercise. Existing patients find using a lower dose as a maintenance dose can help maintain the lower weight.

Will the weight come back after stopping the injections?

After stopping treatment, weight that people lose does tend to be regained, particularly in instances where weight loss was too quick, or where the correct lifestyle changes were not incorporated effectively.

How do these injections compare to weight-loss surgery?

Weight loss surgery has shown greater weight loss compared to injections but with a notably higher risk of complications. Which is right for you, depends on your individual circumstances.


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Aliysha Parveen

Pharmacist Independent Prescriber

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