The world of weight-loss medication is changing fast. From 1st September 2025, patients paying privately for Mounjaro (tirzepatide) in the UK will face steep price rises of up to 170%. For many, this raises an important question: is switching to another medication, such as Wegovy, an option, or should I continue with my current treatment – or potentially consider surgery?
At Streamline Weight Loss, we believe your health decisions should never be driven solely by cost. If Mounjaro is working well for you, it may still be best to remain on it despite the price increase. However, if the new cost is unsustainable, there are alternatives worth considering.
In this blog, we’ll explain:
- Why Mounjaro prices have risen
- How Wegovy compares to Mounjaro in clinical trials
- The cost differences between the two treatments
- What to consider if you’re thinking of switching medication
- Why price shouldn’t be the only factor in your decision
Why Are Mounjaro Prices Increasing in the UK?
From September 2025, Eli Lilly, the manufacturer of Mounjaro, will increase the UK private prescription list price by up to 170%. The monthly cost for higher doses will rise from around £122 to approximately £330, while lower and mid-range doses will increase from £92 to £180. Consumer prices are also likely to rise significantly.
The company has explained this move as part of a strategy to align UK prices more closely with international markets. However, under a new commercial agreement with Eli Lilly, Streamline can obtain Mounjaro at a discounted price, which we pass on to our patients, allowing us to maintain a competitive pricing structure.
Understandably, this news has prompted many patients to reassess their options and consider other weight-loss medications, most notably Wegovy.
Mounjaro Vs Wegovy: Which Weight Loss Medication is More Effective?
Both Mounjaro and Wegovy are weekly injectable medications designed to support weight loss. They mimic gut hormones that help regulate appetite and improve feelings of fullness.
Active Ingredients
- Wegovy contains semaglutide, a GLP-1 receptor agonist.
- Mounjaro contains tirzepatide, which targets both GIP and GLP-1 receptors.
Both treatments can support effective weight loss when combined with a balanced diet and healthy lifestyle, including exercise.
How Do Mounjaro and Wegovy Work in the Body?
GLP-1 is a natural hormone released after eating that signals fullness to the brain. It also slows stomach emptying and helps regulate blood sugar by improving insulin release. Semaglutide and tirzepatide mimic this hormone, helping you feel satisfied with smaller portions, making it easier to reduce calorie intake without constant hunger.
Mounjaro has the added effect of activating the GIP pathway (glucose-dependent insulinotropic polypeptide), which helps stimulate insulin release after meals and may improve how your body processes fat, reducing long-term storage. By acting on both GIP and GLP-1 pathways, tirzepatide may offer enhanced weight-loss benefits for many people.
Clinical Trial Results: Wegovy vs Mounjaro Weight Loss Outcomes
According to a major head-to-head clinical trial reported by the BBC:
- After 72 weeks, patients on Mounjaro lost around 20% of their body weight.
- Patients on Wegovy lost approximately 14% of their body weight.
This study suggests Mounjaro is highly effective overall, but Wegovy still delivers clinically significant results for many patients. Both Eli Lilly and Novo Nordisk have conducted extensive research showing excellent weight loss outcomes.
Side Effects of Mounjaro and Wegovy: What Patients Should Expect
Both medications can cause nausea, vomiting, gastrointestinal upset, or diarrhoea during the first weeks of treatment. Some patients find Mounjaro’s side effects more intense due to its dual mechanism.
You can read more about the side effects of these medications in the blog below:
What are the side effects of weight loss injections?
Cost Comparison: Mounjaro vs Wegovy in the UK
From 1st September 2025, private prescription costs for Mounjaro could rise by up to 170%, with some doses now costing pharmacies as much as £330 per pen per month.
By comparison, Wegovy (semaglutide) remains more affordable, with typical monthly costs between £100 and £200 depending on dosage.
At Streamline Weight Loss, we understand how disruptive this shift feels for patients. That’s why we’ve introduced our Price Protection Promise, which guarantees existing Mounjaro patients are shielded from the steepest increases, allowing them to continue treatment at a stable, predictable price for the remainder of 2025.
If you are an existing Streamline Weight Loss patient, or are considering switching to us from another provider, please contact our Patient Advisor Team to find out more.
Should You Switch from Mounjaro to Wegovy? Key Factors to Consider
Here are the key factors to consider before making the switch:
Effectiveness vs Affordability
Mounjaro is a popular choice in the UK, with many patients reporting good weight loss results. If cost becomes a limiting factor, Wegovy can still deliver excellent outcomes at a lower price point—for now.
However, Wegovy’s manufacturer, Novo Nordisk, may respond to rising demand by increasing its own pricing, which could affect consumers similarly to Mounjaro.
At Streamline Weight Loss, our position is clear: If Mounjaro is working for you and you can continue treatment without financial strain, it’s worth staying on it. Health outcomes should not be dictated solely by price.
Transition Requires Medical Guidance
Switching isn’t always as easy as swapping pens and we recommend speaking to a healthcare professional, who will advise on:
- The correct Wegovy starting dose for your current Mounjaro programme
- Managing potential side effects
- Ensuring continuity of weight-loss results
Our specialist endocrinologist advises it may be possible for selected patients to switch directly from Mounjaro to Wegovy. Please contact us for more information on this.
Lifestyle Support Remains Critical
Medication is a powerful tool, but long-term results depend on pairing treatment with nutritional support, physical activity and behavioural & lifestyle changes.
Could Surgery Be a Better Option for You?
For some individuals, weight loss surgery may be worth considering, especially when looking at the long-term costs of GLP-1 medications like Mounjaro. Over three years, the cumulative cost of these medications can approach the price of procedures such as a gastric sleeve. In such cases, surgery may offer a more cost-effective and long-term solution.
Final Thoughts: Choosing Between Mounjaro, Wegovy, or Surgery with Streamline Weight Loss
The Mounjaro price increase has understandably caused concern among private patients. While Wegovy is now the cheaper option, we believe the decision to switch should be guided by health first, and price second:
- If Mounjaro works for you and is sustainable, stick with it.
- If affordability is an issue, Wegovy offers a proven, cost-effective alternative.
At Streamline Weight Loss, we are experts in obesity treatment. Our team of clinicians can help you weigh up your options, both surgical and non-surgical, guide you through medication switches, and provide the lifestyle support you need for long-term success.
