In the UK, weight loss injections have gained significant popularity over the past few years, particularly since around 2021. Around 30% of the UK population is dealing with obesity, leading to a high demand for weight loss medications. Two of the most talked about weight loss medications are Mounjaro (Tirzepatide) and Wegovy (Semaglutide).  Both drugs work in different ways and have distinct characteristics, but are designed to aid in weight loss.

Mounjaro vs. Wegovy: Key Differences 

If you are considering a weight loss injection, understanding the differences between Mounjaro and Wegovy helps you determine which one is the best option for you. 

Mounjaro (Tirzepatide) 

Mounjaro is an injectable weight-loss medication. It was originally designed and approved for type 2 diabetes by Eli Lilly. Over time, it has shown significant results in weight loss leading to its consideration for the treatment of obesity. Mounjaro works by mimicking two hormones—GLP-1 (Glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). 

Wegovy (Semaglutide)

Wegovy is also a weight loss injection, developed by Novo Nordisk. Its active ingredient is semaglutide and belongs to the class of GLP-1 receptor agonists. Wegovy was specifically designed for obesity management—helps regulate hunger and calorie intake by slowing digestion and reducing appetite. 

Criteria for Body Mass Index (BMI)

To qualify for a prescription for Mounjaro and Wegovy, the healthcare provider will assess you based on your medical history, current medications and body mass index (BMI). These weight loss medications will be prescribed if you meet the following BMI requirements; 

• BMI of 27 kg/m2 or higher (overweight) with a weight-related health condition such as pre-diabetes or hypertension

• BMI of 30 kg/m2 or higher (obesity) 

You can calculate your BMI here to check if you qualify for the treatment and determine the best weight management options for you.

Mounjaro vs. Wegovy: Active Ingredients

When comparing Mounjaro and Wegovy, it is important to understand their active ingredients and mechanism of action as both weight loss injections help with weight loss by targeting hormones that control hunger, but work differently in the body;

Active Ingredients

Mounjaro (Tirzepatide)

Mounjaro contains Tirzepatide as an active ingredient—a dual GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist

Wegovy (Semaglutide)

Wegovy contains Semaglutide as an active ingredient—a GLP-1 receptor agonist 

Mechanism of Action of GLP-1 and GIP

GLP-1 (glucagon-like peptide-1) 

GLP-1 is secreted by the L-cells of the small intestine and works by binding the GLP-1 receptors leading to;

• Enhanced insulin secretion and suppressed glucagon release work together to help lower blood sugar levels
• Slower gastric emptying leads to longer satiety and low food intake
• Activates receptors in the brain to reduce hunger leading to appetite suppression  

GIP (glucose-dependent insulinotropic polypeptide) 

GIP is secreted by K-cells of the small intestine and acts by;

• Stimulating insulin release which improves blood sugar control 
• Promoting fat metabolism 
• Controlling appetite 

Mounjaro activates both GLP-1 and GIP receptor agonists—this dual action is highly effective for weight loss and enhances insulin secretion, slows digestion and reduces hunger

Wegovy primarily targets GLP-1 receptors—this increases insulin production, reduces appetite and slows gastric emptying.  

Mounjaro vs. Wegovy: Dosage and Administration 

Both Mounjaro and Wegovy follow a structured 4-weekly dosage schedule. However, if you experience severe side effects, your healthcare provider may advise you to delay or maintain the current dose. 

Effectiveness: Which One Delivers Better Results, Mounjaro or Wegovy?

In terms of weight loss outcomes, several studies have shown a comparison between Mounjaro and Wegovy to show their effectiveness—studies have shown that Mounjaro works better than Wegovy. 

• Mounjaro has demonstrated an average weight loss of 15% of total body weight depending on the dosage given. A clinical trial of 72 weeks among non-diabetic patients showed significant weight loss of up to 22.5% with the highest maintenance dose of 15 mg.  
• A 68-week study showed that participants taking Wegovy lost an average of 15% of their body weight.

Studies provide evidence that tirzepatide is both non inferior and superior to semaglutide for type 2 diabetes management. Mounjaro’s dual action on GLP-1 and GIP receptors result in a slightly greater weight loss than Wegovy, though individual results can vary.  

Mounjaro vs. Wegovy: Side Effects 

Some common side effects of Mounjaro and Wegovy include;

Choose The Weight Loss Option Suitable For You

Yes, Mounjaro (tirzepatide) is available in the UK. It was approved by the National Institute for Health and Care Excellence (NICE) for treating obesity and also by the Medicines and Healthcare products Regulatory Agency (MHRA) for weight management in individuals with a BMI of 30 kg/m2 or more as well as those with a BMI between 27-30 kg/m2 who have weight-related health conditions. 

Batley Pharmacy can offer Mounjaro and Wegovy as a part of the weight loss service if suitable after booking an appointment, visiting our pharmacy and having an in-person consultation with our healthcare professional.

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