The Independent Pharmacy

Saxenda vs Mysimba - We Explain The Difference

Daniel Hurley
Daniel HurleyMPharm IPPharmacist Independent Prescriber

Reviewed on 11 Oct 2023

At The Independent Pharmacy, we understand that the struggle to lose weight is a challenging journey for many people in the UK. Despite efforts to eat well and exercise, the scales sometimes don't seem to budge. That's why some turn to prescription weight loss medications like Saxenda and Mysimba for help. But what's the difference between these two drugs, and which one is right for you?

This guide provides an unbiased comparison of Saxenda and Mysimba to help you understand the key factors: effectiveness, side effects, cost, and accessibility. With the right information, you can work with your UK doctor to determine if one of these medications may support your weight loss journey. Losing those stubborn pounds is within reach when you have the tools you need, including a healthy diet, increased physical activity like moderate exercise, and potentially effective FDA-approved weight loss drugs.

LiraglutideBupropion Hydrochloride,
Naltrexone Hydrochloride
of Action
GLP-1 receptor agonist,
decreases appetite,
increases fullness
Influences brain chemicals
to reduce appetite and
control cravings
Effectiveness5-10% average weight loss5% average weight loss
of Results
Faster, within the first monthSlower, takes longer to ramp up
Weight loss, sometimes
for type 2 diabetes
Weight loss, obesity or
overweight withat least
one weight-related
health condition
Nausea, vomiting,
diarrhea, constipation, etc.
Nausea, constipation,
headache, vomiting,
dizziness, etc.
AccessibilityPrescription required,
daily self-injection
Prescription required,
pill taken twice per day
WarningsNot recommended for those
with certain endocrine tumors
or severe kidney/liver problems
Not recommended for those
taking certain medications or
with uncontrolled high blood pressure

What is Saxenda?

Saxenda is a prescription injectable weight loss medication. It contains the active ingredient liraglutide and is approved for use in the UK. Saxenda helps promote weight loss by decreasing appetite, increasing feelings of fullness, and lowering food intake.

How Does Saxenda Work?

Saxenda's active ingredient is liraglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist. Saxenda mimics the effects of GLP-1, a hormone that helps regulate appetite and food intake.

By acting on receptors in the brain, Saxenda helps you feel fuller faster, stay satisfied longer, and resist cravings. It also slows the emptying of the stomach and decreases food absorption. Saxenda is self-administered once daily by injection using a prefilled pen device.

View Mounjaro Weight Loss Treatment

Common Uses

In addition to weight loss, Saxenda is sometimes prescribed off-label in the UK to help manage type 2 diabetes, offering a multifaceted approach to health. However, the most common use is as an effective FDA-approved weight loss aid.

How to Take Saxenda

Saxenda is taken once a day through an injection under your skin (subcutaneous injection). For most people, injecting Saxenda into your abdomen, thighs, or arms is easiest and least painful.

When first starting Saxenda, a low 0.6 mg daily dose is recommended for the first week so your body can get used to it. Then, the dose is gradually increased over the next 5 weeks until it reaches the typical 3 mg daily target maintenance dose. This slow ramp-up reduces side effects.

Saxenda comes in prefilled, easy-to-use pen injectors containing the right doses. This helps make taking the daily injections as simple and stress-free as possible. Don't worry about becoming an expert - with some practice, most people find Saxenda pens easy to fit into their routine.

Side Effects

Potential side effects of Saxenda include nausea, vomiting, diarrhoea, constipation, low blood sugar, dizziness, headache, fatigue, gallbladder issues, increased heart rate, kidney problems, pancreatitis, and allergic reactions. Saxenda also carries a black box warning for thyroid tumours. We know that considering potential side effects like nausea, vomiting, and others can be daunting, so it's crucial to consult your doctor for a comprehensive understanding of the risks. Be sure to read the patient information leaflet thoroughly and consult your doctor on risks.

What is Mysimba?

Mysimba is a prescription weight loss pill available in the UK. It contains a combination of the active ingredients bupropion and naltrexone. Mysimba works by influencing brain chemicals to reduce appetite and control cravings.

How Does Mysimba Work?

Mysimba contains a combination of two active ingredients: bupropion hydrochloride and naltrexone hydrochloride.

Bupropion is an antidepressant medication that affects chemicals in the brain to help regulate mood and suppress appetite. Naltrexone blocks the effects of opioids and also reduces hunger signals. Together, these ingredients influence the reward and feedback mechanisms that control food cravings and overeating.

Common Uses

Mysimba is often prescribed to provide a helping hand in the weight management journey for UK adults dealing with obesity or other weight-related health conditions.

How to Take Mysimba

Mysimba comes in oral tablet form that you swallow whole. For the first week, it is recommended to start with one low dose of 8mg/90mg tablet each morning so your body can adjust.

Over the following 3 weeks, the Mysimba dose is slowly increased by adding a second tablet each day until reaching the typical two 32mg/360mg tablet daily maintenance dosage (one in the morning, one in the evening).

Taking Mysimba with food may help reduce potential stomach upset. Be sure to swallow the tablets whole without crushing, cutting or chewing them. This gradual ramp-up and taking Mysimba properly at consistent times each day will help manage side effects.

Side Effects

Possible side effects of Mysimba include nausea, constipation, headache, vomiting, dizziness, dry mouth, diarrhoea, and insomnia. Be sure to discuss any preexisting health conditions with your doctor before starting Mysimba. We understand that the possibility of side effects can be concerning, so it's essential to have an open dialogue with your healthcare provider.

How Do They Compare?

Saxenda and Mysimba have key differences when it comes to effectiveness, side effects, cost, and accessibility. Saxenda produces more weight loss on average but has more gastrointestinal side effects. Mysimba is less expensive but may be less effective for substantial weight loss. Saxenda requires injection, while Mysimba is a pill. This section provides a detailed comparison of these factors so you can determine which medication may be better suited to your needs and situation.


Clinical trials have shown that both Saxenda and Mysimba can be effective for weight loss, but Saxenda appears to produce greater average weight loss.

In trials, people taking Saxenda lost around 5-10% of their initial body weight compared to 5% for those taking Mysimba. However, individual results can vary significantly.

Saxenda also tends to produce weight loss more rapidly than Mysimba. Many people on Saxenda see results within the first month, while Mysimba takes longer to ramp up weight loss.

Side Effects

The most common side effects for both Saxenda and Mysimba are gastrointestinal issues like nausea, vomiting, and diarrhoea. Saxenda has higher reported rates of these side effects, which could potentially lead to stomach pain.

Mysimba is more likely to cause headaches, insomnia, and dizziness. The side effects of both medications tend to be worse when first starting treatment and often subside over time.

Neither Saxenda nor Mysimba cause severe side effects for most people. However, Mysimba may have slightly less intense side effects overall.


Saxenda is significantly more expensive than Mysimba.

Both medications require a private prescription from a doctor, and you might be able to get Saxenda on the NHS if you qualify. But if you don't qualify and need to pay the full price, Saxenda's higher cost can make it prohibitively expensive for some patients.


A prescription is required for both Saxenda and Mysimba, so an initial consultation with a doctor is needed either way. Saxenda requires administration by daily self-injection using an injection pen, while Mysimba is a pill taken twice per day.

Mysimba may be slightly more accessible since it doesn't require dealing with needles or injection pens. Both drugs are generally widely available at UK pharmacies once you have a private prescription.

Who Should Use Saxenda?

Saxenda may be a good option for those with a lot of weight to lose or other obesity-related health conditions. The greater average weight loss compared to alternatives like Mysimba can provide added benefits.

Saxenda also suits highly motivated people committed to making lifestyle changes like improved diet and added exercise along with the medication for maximum results.

The daily self-injected dosing could be a good fit for those wanting a regular routine reminder to stay on track with their weight loss goals.

Saxenda Warnings

Saxenda is not recommended for those with a personal or family history of certain endocrine tumours or multiple endocrine neoplasia syndrome. People with severe kidney or liver problems should also avoid Saxenda.

Caution should be used in patients with preexisting conditions like kidney/liver disease, congestive heart failure, gastrointestinal disease, or a history of pancreatitis.

Who Should Use Mysimba?

Mysimba may be preferable for people who want to take a pill rather than use injectable medication. The more gradual weight loss profile can also suit those looking for a slower progression.

People who have struggled with the more intense gastrointestinal side effects of other weight loss drugs like Saxenda could potentially tolerate Mysimba better.

Mysimba is also appropriate for those with less weight to lose and more modest goals for weight management rather than dramatic loss.

Mysimba Warnings

People taking monoamine oxidase inhibitors, opioids, or cyclobenzaprine should not use Mysimba due to potential drug interactions. Individuals with uncontrolled high blood pressure, anorexia or bulimia, or bipolar disorder should also avoid Mysimba.


What is better than Saxenda for weight loss?

Some medications that may produce greater weight loss than Saxenda include Wegovy, Ozempic, and Tirzepatide. Bariatric surgery is also an option for some people. However, Saxenda is one of the more effective prescription medications for weight loss available.

What is stronger than Saxenda?

Wegovy contains a higher dose of the same active ingredient as Saxenda (liraglutide) and can generate more weight loss. Tirzepatide is a new medication still in trials but appears to be more potent than Saxenda.

How effective is Mysimba for weight loss?

Clinical trials show Mysimba produces an average weight loss of around 5% of initial body weight when taken with diet and exercise. However, some people lose much more or less on Mysimba. It is considered moderately effective compared to other prescription weight loss options.

Does Mysimba really work?

Yes, Mysimba is an FDA-approved medication shown to be effective for weight loss and maintenance for some individuals. But results vary quite a bit based on the person. Combining Mysimba with improved nutrition and physical activity maximises potential success.


Saxenda and Mysimba take different approaches to prescription weight loss, but both can be viable options depending on your circumstances and needs. Saxenda produces more weight loss on average but requires daily injections and has a greater risk of gastrointestinal side effects. Mysimba is cheaper and easier to take but may be less effective for substantial weight loss.

We encourage you to have an open conversation with your healthcare provider to explore whether Saxenda or Mysimba could be a supportive addition to your holistic weight management plan. They can help determine if prescription medication is appropriate and provide guidance on additional measures to optimise your results. With the right combination of tools paired with self-acceptance and recognising that beauty and worth are not defined by weight, you can achieve your goals related to improved wellbeing and self-care.

Start Your Weight Loss Treatment Today

At The Independent Pharmacy, we wholeheartedly believe that weight loss is a deeply personal journey, one that truly requires understanding, compassion, and personalised care. Speak with your doctor or healthcare provider to learn if Saxenda, Mysimba or other medication options may support your needs. Together, you can discuss and determine if prescription medications, along with positive lifestyle changes, could help you meet your health and wellness goals in a healthy, sustainable way.


Short-term combined treatment with liraglutide and metformin leads to significant weight loss in obese women with polycystic ovary syndrome and previous poor response to metformin - PMC (

Obesity - Treatment - NHS (

Related Guides

Need something else?

We stock 1044 treatments for 90 conditions

Or browse all treatments or conditions

A customer at the pharmacist looking for medication