Mounjaro or Wegovy: Which weight loss treatment is right for you?

What are the different weight loss drugs?

Wegovy

Manufacturer: Novo Nordisk
Active Ingredient: Semaglutide (same as Ozempic, the US equivalent)
What it does: Semaglutide but is specifically approved at a higher dose for weight loss.
Dosing: A once-weekly injection at up to 2.4 mg weekly.
Key Difference from Ozempic: Wegovy is formulated and dosed specifically for weight loss, whereas Ozempic is focused on diabetes management.

Mounjaro

Manufacturer: Eli Lilly
Active Ingredient: Tirzepatide
Dosing: Once-weekly injection.
What it does: Contains tirzepatide, a dual GIP and GLP-1 receptor agonist (designed to improve both blood sugar control and appetite regulation).
Claims: Studies suggest it may lead to greater weight loss compared to semaglutide-based treatments in some individuals.

Who are the weight loss drugs most suitable for?

There are strict criteria for getting a weight loss drugs (like Mounjaro or Wegovy) prescription in the UK

Each of these treatments has broad eligibility criteria, and there are some reasons why a particular treatment may or may not be appropriate for you.

General Eligibility Criteria

BMI (Body Mass Index): Often required to be 30+ or at a lower 27+ with a weight-related condition like type 2 diabetes.
Age: Typically approved for adults over 18 years old.
Commitment to lifestyle changes: Most prescribers recommend combining these treatments with dietary adjustments and physical activity.

When a treatment might not be suitable

Pregnancy or breastfeeding: None of these medications are recommended during pregnancy or breastfeeding.
History of thyroid cancer or MTC (medullary thyroid carcinoma): GLP-1 receptor agonists are not recommended if you or a family member have had MTC.
Endocrine condition (MEN2): Multiple endocrine neoplasia type 2 is a contraindication for these treatments.
Allergic to ingredients: For example, if you’re allergic to semaglutide or tirzepatide, your prescriber will avoid treatments containing them.
Gastrointestinal (GI) diseases: Conditions like gastroparesis may make these medications unsuitable.
Other medications: Taking other GLP-1 receptor agonists or similar treatments could rule out additional prescriptions.

Key differences between Ozempic, Wegovy, and Mounjaro

Ozempic

Active Ingredient: Semaglutide
Purpose: Diabetes + Weight Loss
Dosage: Lower (diabetes focus)
Unique Aspect: Proven diabetes control
Side Effects: Nausea, GI issues

Wegovy

Active Ingredient: Semaglutide
Purpose: Weight Loss
Dosage: Higher (weight loss)
Unique Aspect: Higher weight-loss dose
Side Effects: Similar to Ozempic

Mounjaro

Active Ingredient: Tirzepatide
Purpose: Diabetes + Weight Loss
Dosage: Dual-action
Unique Aspect: Dual mechanism (GIP + GLP-1)
Side Effects: Potentially more nausea

What about pricing?

Obviously, the costs depend on how long you may be on the treatment. Many of the drug efficacy studies are based on a 76 week treatment plan, around 18 months.

Wegovy: Cheaper than Mounjaro but not deemed quite as effective: SlimrChat’s analysis suggests that a 76 week treatment of Wegovy on average costs around £3,700 .
Mounjaro: Pricing may be higher, but its dual-action mechanism is a unique benefit for some users: SlimrChat’s analysis suggests that a 76 week treatment of Mounjaro costs on average around £5,500.

The world of pricing is confusing and many pharmacies offer very good ‘first purchase’ discounts – but beware these discounts can hide higher prices for the higher doses you will need later. You can move pharmacies to find better pricing and we, at SlimrChat, monitor and compare pricing so that you can ensure you are always finding the best prices:

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It is worth noting that given the strict NHS eligibility rules for getting weight loss drugs on the NHS, it is likely only extreme cases will get NHS prescriptions for these drugs. Check with your GP, but it is most likely you will have to buy Wegovy or Mounjaro privately from a registered pharmacy.

Final thoughts

Each treatment has unique benefits and considerations. The right choice for you depends on your medical history, goals, and lifestyle. Your prescriber will help you navigate these options and determine the safest, most effective path forward. Once you have decided which weight loss drug is best for you, you need to get a prescription – see our article, ‘How Do I get A Prescription?’.