If you’re looking to lose weight, you may be wondering “What is the best injection for weight loss?”. Well, the right choice for you depends on factors such as your BMI, your side effect tolerance, and your medical history. The three main weight loss pens in the UK include Mounjaro, Saxenda and Wegovy. 

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We’re here to help you understand the best option for you. Read on to find out the pros and cons of Mounjaro, Saxenda, and Wegovy, and to determine which is the best choice for you and your goals.

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Tirzepatide (Mounjaro)

Mounjaro (active ingredient tirzepatide) is an antidiabetic and weight loss medication. This prescription medication can be used to treat type 2 diabetes, helping to manage blood sugar levels. 

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Like other weight loss medications such as Wegovy, you take Mounjaro as a once-weekly injection. It works by stimulating GLP-1 and GIP receptors, which in turn, affects your appetite and blood sugar. 

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It can help to lower your appetite and leave you feeling fuller for longer. This makes it much easier to achieve a reduced-calorie diet and lose weight. 

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That being said, Mounjaro is not suitable for everybody. For example, if you have a personal (or family) history of: 

• Multiple endocrine neoplasia syndrome type 2
• Severe active gastrointestinal problems
• History of Medullary thyroid carcinoma

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A multi-dose version of Mounjaro - the Mounjaro KwikPen - was approved by the MHRA back in January 2024 to treat people with diabetes. It contains a 4x dose prefilled injection pen. 

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Always speak with a medical professional before taking Mounjaro, and be sure to disclose your medical history. Your doctor will determine whether Mounjaro is a good fit for you or not. 

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Mounjaro Pros

• Reduced blood sugar levels - proven to reduce blood sugar levels in those with type 2 diabetes
• Convenient - you take it just once a week via injection
• Effective in promoting weight loss - this medication can lead to significant weight loss in those with obesity and diabetes 
• Can lose up to 20% of your body weight in the first year 

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Mounjaro Cons

• Must have a BMI of 27 + with weight-related health problems such as diabetes, or a BMI of 30+ to be eligible
• Can cause unpleasant side effects - common side effects such as nausea, vomiting, constipation and diarrhoea 

Can cost as much as £250 per month (but as little as £149 per month with Dr Frank’s!)

Liraglutide (Saxenda)

Saxenda contains the active ingredient ‘liraglutide’. It is a weight loss medication that has been approved for use in the UK since 2017. It became available on the NHS in October 2020 - and was the first weight loss drug to be endorsed for weight management in close to 10 years. 

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Like other weight loss pens, Saxenda replicates the GLP-1 hormone. In turn, this helps to regulate your blood sugar levels and suppresses your appetite. It can help you feel full for longer and reduce food cravings, ultimately helping you to lose weight. For best results, we recommend using Saxenda alongside a healthy diet and other healthy lifestyle choices. 

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To take Saxenda, you simply inject it under your skin with the injection pen. 

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Saxenda Pros 

• Effective for weight loss - you can lose around 7.5% of your body weight 
• Helps to control blood sugar levels in those with diabetes (or prediabetes) 
• Available through the NHS if you have a BMI of 35+, non-diabetic hyperglycaemia, and are at risk of heart problems 
• It can help you maintain a healthy lifestyle 
• It’s convenient and easy to take 

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Saxenda Cons

• There is a risk of side effects such as stomach ache, constipation, nausea, vomiting and diarrhoea (although these are usually mild and temporary)
• You could experience injection site reactions (e.g swelling or itching) 
• If you opt for Saxenda through the NHS, you can only use it for 3x months unless you lose 5% of your body weight 
• It’s not suitable for everyone - especially if you have health conditions such as pancreatitis, thyroid disorders, or a history of medullary thyroid cancer
• Each pen can cost over £50 

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Semaglutide (Wegovy, Ozempic and Rybelsus)

Semaglutide is the active ingredient in three weight loss or diabetes management medications - Wegovy, Ozempic and Rybelsus. However, Ozempic and Rybelsus are not approved for weight loss treatment in the UK - they are only prescribed for diabetes management. 

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Wegovy, however, is approved as a weight loss medication. However, it is only available through the NHS if you have a BMI of 35 or higher, and you have at least one weight-related health problem. 

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This weight loss drug works by mimicking the human glucagon-like peptide-1 hormone (GLP-1). This is the hormone that targets the areas of your brain responsible for regulating appetite and food intake. Wegovy is 94% similar to this naturally occurring hormone. 

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Wegovy Pros

• Almost 9 out of 10 people lose more than 10% of their body weight when taking Wegovy (alongside, of course, healthy lifestyle changes such as diet and physical activity) 
• Wegovy can lead to significant weight loss after just one year 
• It can reduce feelings of hunger and increase feelings of fullness 
• It can improve your blood sugar levels, cholesterol and blood pressure
• It’s easy to take as a once-weekly injection

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Wegovy Cons

• Like all weight loss pens, this is not a substitute for a healthy lifestyle - you need to commit to positive changes to see long-term results
• There is a small risk of side effects such as nausea, bloating, heartburn, constipation, headaches and more 
• There is no generic version available, so you have to pay for branded semaglutide pens
• This can cost over £200 per month depending on the dose (but just £149 with Dr Frank’s!) 

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So Which is the Best Weight Loss Injection?

Now you’ve read the pros and cons of each, you may be wondering which is the best fit for you. However, one size does not fit all when it comes to weight loss, and what works for you may not work for somebody else, and vice versa. 

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Always discuss your goals, preferences and requirements with your doctor or healthcare professional to determine the best option. 

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So, we can’t tell you the best choice for you without seeing your medical history and goals. However, we can determine which appears to be most effective… and that is Mounjaro! 

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Researchers estimate that people can lose up to 26.6 of their body weight when taking Mounjaro, which is an average weight loss of 60 pounds in under two years. The results appear to be more impressive than other weight loss medications such as Ozempic and Wegovy. 

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Another study reviewed the effectiveness of tirzepatide (Mounjaro) vs semaglutide, across a range of clinical trials and found that in people living with Type 2 Diabetes and overweight or obesity:

• Those taking a higher dose (15mg)  of tirzepatide (Mounjaro) lost around 21lbs
• Those taking a lower dose (5mg) lost 11.6lbs 
• Those taking a higher dose (2.0mg) of semaglutide lost around 10.9lbs
• Those taking a lower dose (0.5mg) lost around 5.5lbs

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This study suggests that Mounjaro is more effective at helping people lose weight than other options such as Wegovy. 

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Begin your weight loss journey today with Dr Frank’s Weight Loss Clinic. 

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