Mounjaro Vs Saxenda: Side Effects, Differences & Similarities

In the UK, it is estimated that 1 in 4 adults are living with obesity. Obesity and excess weight are complex health issues that can elevate the risk of developing severe complications like coronary heart disease, stroke, certain cancers and type-2 diabetes. Being overweight can also negatively impact mental health and quality of life.

Managing complex conditions such as obesity and excess weight can be challenging, as it takes time and commitment. Weight loss medications such as Mounjaro and Saxenda can be used successfully in conjunction with a calorie-reduced diet and increased physical activity to achieve weight loss goals.

In the article below, we’ll compare both Mounjaro and Saxenda, taking a look at the ingredients used, side effects, differences, similarities, user reviews and costs of both weight loss pens. Read on to find out more.

Mounjaro Overview: How Does Mounjaro work?

Mounjaro is a prescription medication appropriate for:

  • Adults with type-2 diabetes
  • Adults who are overweight (BMI greater than 27) and have weight-associated health conditions
  • Adults who have obesity (BMI greater than 30)

Mounjaro is an alternative to Saxenda for weight loss. It’s injectable, contains the active ingredient tirzepatide and is available in multiple dosages. Tirzepatide attaches to the receptors GIP and GLP-1, which are naturally occurring hormones released from the gut after eating.

When used in adults with type-2 diabetes, Mounjaro reduces sugar levels in the body. It primarily works by controlling appetite, making you feel less hungry and helping you lose body weight by eating less food.

Saxenda Overview: How Does Saxenda Work?

Saxenda is a prescription medication appropriate for:

  • Adults with excess weight (BMI greater than 27) who have weight-associated medical problems
  • Adults or who have obesity (BMI greater than 30)
  • Children aged 12-17 with a body weight over 60 kg (132 pounds) and obesity

Saxenda has the active ingredient liraglutide and comes as a 3mg injection. This medication is intended to be used with physical activity and a reduced-calorie diet. It is not known if Saxenda is safe for use in children under the age of 12 years old or in 12-17-year-old children with type-2 diabetes.

The body naturally makes an appetite hormone called glucagon-like peptide-1 (GLP-1) that helps to control hunger. Saxenda works similarly to GLP-1 by controlling appetite, which can lead to losing weight by eating fewer categories.

Is Mounjaro The Same as Saxenda? Similarities and Differences

Active Ingredients

The active ingredient in Mounjaro is tirzepatide, which is a glucagon-like peptide-1 (GLP-1) receptor and a glucose-dependant insulinotropic polypeptide (GIP) receptor.

The active ingredient in Saxenda is liraglutide, which is a glucagon-like peptide-1 (GLP-1) receptor.

How Long Do They Take to Work?


Research shows that when starting Mounjaro, weight loss can be noticed from as early as four weeks. During a 40-week study, consistent and further weight loss was observed in patients. Patients who were on the optimal dose of Mounjaro (15mg) saw an average of 11.3kg total weight loss at the end of the 40-week study.


In a 56-week study, 3 out of 5 patients taking 3mg of Saxenda experienced weight loss of 5% or more, an average of 5.4kg (12 lbs). 1 out of 3 patients taking Saxenda experienced weight loss of 10% or more.

Mounjaro vs Saxenda Dosing and Usage Recommendations


Mounjaro has multiple dosage amounts that are administered once a week. Mounjaro 2.5mg is always the starting dose for every patient, with a typical treatment dosage plan looking like:

If you use more Mounjaro than prescribed, contact your doctor immediately, as too much can cause low blood pressure, which is dangerous.

Mounjaro comes as a prefilled injection pen that helps you administer your prescribed dose subcutaneously (under the skin). You will need to inject the medicine yourself into your thigh, stomach, or upper arm. To understand how to use the injection pen, please refer to the details guide that comes with your medicine. If you have any questions, talk to your doctor or pharmacist.


Saxenda treatment begins at a very low dosage, which is gradually increased over the first five weeks of treatment. The dose is then maintained at 3mg unless otherwise directed by your doctor.

  • Month 1: Starting dose 0.6mg once daily
  • Month 2: 1.2mg once daily
  • Month 3: 1.8mg once daily
  • Month 4: 2.4mg once daily
  • Month 5 onwards: 3mg once daily

Once you reach the recommended dose of 3mg, keep using this dose until the end of your treatment period. Do not increase the dose past 3mg. Your doctor will monitor your treatment during your weight loss journey.

Saxenda also comes in a prefilled injection pen that is given under the skin. Before using the pen for the first time, there are detailed instructions on the patient information leaflet that we recommend reading.

How Does it Feel After a Mounjaro Injection vs Saxenda?


When taking Mounjaro for the first time, common side effects such as nausea, vomiting, reduced appetite and diarrhoea may be experienced. Most people taking Mounjaro find that these mild side effects lessen and go away after a couple of days. If these symptoms worsen and you are struggling to keep fluids down, talk to your doctor or pharmacist.


When first starting Saxenda injections, you may experience nausea, which decreases over time as you get used to the medication. However, if you continue to experience persistent nausea or other side effects, talk to your doctor or pharmacist about nutrition and alternative options to help manage symptoms.

Mounjaro vs Saxenda Side Effects

As with any medication, there are known side effects when taking Mounjaro or Saxenda, although not everyone may experience them.


Common side effects of Mounjaro include:

  • Nausea 
  • Low blood sugar 
  • Constipation 
  • Diarrhoea 
  • Vomiting 
  • Stomach pain 
  • Indigestion 
  • Stomach pain 
  • Flatulence (gas) 
  • Decreased appetite 
  • Allergic reaction 
  • Injection site reactions 
  • Fatigue 
  • Heartburn or reflux 
  • Burping 
  • Gallstones

If you experience persistent mild side effects, talk to your doctor or pharmacist.

Serious side effects of Mounjaro include:

  • Inflammation of the pancreas (acute pancreatitis)
  • Depression
  • Kidney failure and kidney problems
  • Thyroid cancer and tumours
  • Severe allergic reactions

Call 999 or seek emergency medical attention if you experience any severe side effects. If you would like a complete list of all reported side effects of Mounjaro, please refer to the Patient Information Leaflet.


The most common side effects of Saxenda include:

  • Diarrhoea
  • Nausea
  • Constipation
  • Vomiting
  • Headache
  • Upset stomach
  • Injection site reaction
  • Tiredness
  • Low blood sugar
  • Dizziness
  • Stomach pain
  • Gallstones
  • Difficulty sleeping (insomnia)

Talk to your doctor or pharmacist if you experience persistent common side effects that do not stop.

Severe side effects of Saxenda include:

  • Severe allergic reaction (anaphylaxis)
  • Inflammation of the pancreas (pancreatitis)
  • Severe and persistent pain in the stomach area (abdomen)
  • Thyroid cancer and tumours

If you experience any severe side effects when taking Saxenda, seek emergency medical attention or call 999.

Please refer to the Patient Information Leaflet (PIL) for a complete list of all reported side effects for Saxenda.

Mounjaro vs Saxenda: Key differences

The key differences between Saxenda and Mounjaro include their active ingredients, manufacturers, dosage strengths, dosage frequencies, how quickly they work and which medications they interact with.

Here are the key differences in more detail:

  • Saxenda has the active ingredient liraglutide, while Moujaro has the active ingredient tirzepatide
  • Saxenda is injected every day, while Mounjaro is only injected once a week
  • Mounjaro affects how medications, specifically the pill and paracetamol, are absorbed in the stomach, while
  • Saxenda interacts with Warfarin and other anticoagulant medications
  • Saxenda is manufactured by Novo Nordisk Limited and Eli Lily produces Mounjaro

Mounjaro vs Saxenda’s Interactions With Other Medications


Talk to your doctor or pharmacist before starting Mounjaro if you:

  • Have ever had pancreas inflammation (pancreatitis)
  • Are using insulin or sulphonylurea, as they can cause low blood sugar levels
  • Have severe problems with food digestion or problems with food remaining in your stomach for longer periods (including gastroparesis).
  • Have diabetic retinopathy or macular oedema (problems with your eyes)

The active ingredient in Mounjaro (tirzepatide) also reduces the speed at which your stomach empties. This can affect how other medications, such as the pill (oral contraceptive) and paracetamol, are absorbed by the body. If you take any prescription medications, supplements, vitamins or herbal remedies, talk to your doctor or pharmacist, who can provide advice.


Before taking Saxenda, tell your doctor or pharmacist if you:

  • Take medications for diabetes, such as insulin or medicines called sulfonylurea
  • Take Warfarin or any other medicines used to treat blood clots (anticoagulants)

If you have taken any medications recently, tell your doctor or pharmacist.

Mounjaro vs Saxenda Price

Cloud Pharmacy is a UK-registered online prescribing service that stocks both Mounjaro and Saxenda injection pens. The cost for each is:

  • Mounjaro: Starting from: £138.99
  • Saxenda: Starting from £85

Mounjaro vs Saxenda Customer Reviews

Mounjaro Customer Reviews

Although Monjaro is new to the UK market, it is a very popular option that has proven to be an effective weight loss aid. Most reviews are positive, with reviewers commenting that they only experienced mild side effects, such as nausea, tiredness and headaches, that cleared in a few days as their bodies got used to the medication.

Saxenda Customer Reviews

Saxenda also has positive reviews, with users commenting that it works well and has helped them lose a noticeable amount of weight. Some users found that it took more than three weeks to notice a loss in weight, and others found that they suffered from rough side effects.

Reported side effects include weekly nausea and vomiting that worsened every time the dose increased. However, they found that the weight loss benefits outweighed the side effects.

Mounjaro vs Saxenda: Which Is Better?

Both Mounjaro and Saxenda are proven to result in significant weight loss when combined with lifestyle changes such as exercise and nutrition. However, Mounjaro is the more effective medication compared to the short-acting effects of Saxenda.

Research suggests Moujaro results in 15% more weight loss than Saxenda. Clinical trials found that liraglutide (Saxenda) participants had an average of 6.4% weight loss from starting weight. Meanwhile, in a similar study, participants taking Mounjaro (15mg) lost up to 20% of their starting weight.

What Alternative Weight Loss Pens are Out There?


Wegovy is a prescription medication used for weight loss. It has the active ingredient semaglutide and is administered via injection once a week. Semaglutide works by suppressing the feeling of hunger and helps manage blood sugar levels when they are high. Wegovy can be purchased from Cloud Pharmacy following an online consultation.

Signing Off

While both of these medications are effective weight loss treatment aids, Mounjaro has proven to be more effective in providing significant long-term weight loss.

You can purchase both Mounjaro and Saxenda in the UK from Cloud Pharmacy, a UK-registered online prescribing service.

To determine if you are eligible for either weight loss pen, you will need to fill out a quick online assessment. Once you have completed it, a Cloud Pharmacy medical team member will advise you on which weight loss treatment will be the best option for you.

Once your medication has been dispensed, it will be quickly and discreetly sent to your UK address so that you can continue your weight loss journey. Because we understand the complexities of weight loss and the challenges you face, we provide confidential follow-ups and advice to support you on your weight loss journey.

Begin your weight loss treatment consultation today.


Can you take Mounjaro and Saxenda together?

No. Mounjaro and Saxenda cannot be taken together or with any other GLP-1 medications.

What is better than Saxenda for weight loss?

Current evidence shows that Wegovy and Mounjaro provide more significant weight loss than Saxenda. Although these medicines work in the same way, their results are different.

What Medication Is Comparable to Saxenda?

Alternative medications that are comparable to Saxenda include Wegovy and Mounjaro.

Can you swap from Saxenda to Mounjaro?

You can swap from Saxenda to Mounjaro, but you can't use them interchangeably (at the same time).