The Independent Pharmacy

Ozempic vs Mounjaro - Which Is Best For Your Weight Loss

Scott McDougall
Scott McDougallMPharmDirector & Registered Manager

Reviewed on 5 Apr 2024

When looking at Mounjaro vs Ozempic for helping lose weight, there’s a lot to think through. Both injectable diabetes medications can also assist in weight loss, but research shows Mounjaro facilitates a bit more pounds dropped on average. It also just got fully approved in the UK specifically for managing weight, while Ozempic still focuses on blood sugar control. However, Ozempic has been around since 2019.

There are some key differences and similarities to understand between these options along with your own health background. Doctors suggest taking everything into account together before deciding if adding one of these drugs along with nutrition changes and more activity could be worthwhile for you.

The decision requires weighing your full history and needs to determine what makes the most sense. But used properly under medical supervision, both medications show real promise in studies helping folks lose stubborn pounds.

In this guide, we’ll cover all the differences between Mounjaro vs Ozempic.

Key Takeaways:

  • Both Mounjaro and Ozempic represent hope for many, as studies have shown these injectable medications can support weight loss efforts, complemented by nurturing one’s relationship with food and embracing physical activity.
  • While Ozempic facilitates good weight reduction, too, current clinical trial data gives Mounjaro the edge in terms of slightly greater average pounds lost in direct comparisons.
  • Mounjaro also recently secured full UK regulatory approval specifically for managing weight, while Ozempic remains primarily used for diabetes patients.

Mounjaro vs Ozempic at a Glance

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Feature Mounjaro Ozempic
Active Ingredient Tirzepatide Semaglutide
Function Helps manage blood sugar and assists
in weight loss by making you feel less
hungry and better managing blood sugar
spikes after meals.
Helps manage blood sugar and can
assist in weight loss by reducing food
cravings and helping the pancreas produce
more insulin after meals.
Usage Injectable once weekly with a prefilled pen. Injectable once weekly with a prefilled pen.
Starting Dose 2.5mg weekly, with potential increases up to
15mg weekly based on individual needs and results.
Starts at 0.25 or 0.5mg weekly, with increments
up to a maximum of 2mg as needed.
Common Side Effects Nausea, diarrhoea, decreased appetite, indigestion,
vomiting, constipation, abdominal pain.
Nausea, vomiting, diarrhoea, decreased appetite,
indigestion, constipation, abdominal discomfort,
Serious Side Effects Rare cases of pancreas inflammation, gallbladder
disease, allergic reactions. Warning about potential
thyroid tumours from animal studies.
Rare cases of gallbladder disease, severe pancreas
inflammation, vision changes, kidney injury,
allergic reactions. Warning about potential thyroid
tumours from animal studies.
Weight Loss Effectiveness Clinical trials show an average loss of around 20%
of initial weight over 72 weeks.
Studies show an average reduction of 14.9% in
excess body weight over 68 weeks.
Eligibility Adults with obesity (BMI over 30) and at least one
weight-related health issue. Not for individuals with
certain health problems like thyroid, pancreatic, or
gallbladder disorders.
Primarily for adults with type 2 diabetes.
Regulatory Approval for Weight Loss Yes, in the UK. No specific approval for weight loss in the UK.

Mounjaro vs Ozempic: What Are They and How Do They Work?

Mounjaro and Ozempic are both prescriptions given by weekly injection to help manage blood sugar and weight in certain adults. They belong to a class of drugs called GLP-1 receptor agonists, which work by affecting certain natural processes in the body.


Mounjaro is an injectable prescription medication originally approved for improving blood sugar control in patients with type 2 diabetes. However more recent clinical studies also demonstrate it can effectively aid weight loss for patients struggling with obesity when combined with lifestyle adjustments to eating and physical activity.

The main ingredient in Mounjaro is something called tirzepatide. It helps you feel less hungry by working on certain parts of the body that control appetite. It also helps the body better manage rises in blood sugar levels that happen after consuming carbohydrate-containing foods.


Similar to Mounjaro, Ozempic is also an injection used mainly for people with type 2 diabetes. Studies have shown that it can help people who are obese lose weight, especially when they also eat healthier and exercise. Its active ingredient, semaglutide, lowers food cravings and helps the pancreas produce more insulin to handle blood sugar after meals better.

In human studies, similar to Mounjaro, patients with obesity also making nutrition and activity changes who incorporated once-weekly Ozempic experienced substantial weight reduction over a nearly 1 year period.

Winner: Mounjaro

Mounjaro gets the points for being officially approved for weight loss in the UK, providing a clear regulatory endorsement for this specific use.

Mounjaro vs Ozempic: Effectiveness in Weight Loss


Analysing combined data from multiple clinical trials directly comparing Mounjaro against other injectable diabetes medications shows that Mounjaro facilitates slightly increased body weight loss on average. This is when paired concurrently with adopting advice on improving nutrition intake and increasing physical activity levels.

For instance, in studies, people who were overweight or obese and used Mounjaro lost, on average, around 20% of their initial weight over a period of about 72 weeks. This was when both groups followed supplied tips on lifestyle changes to eating and exercise habits.

So, medical research supports Mounjaro as an effective adjunct option for achieving meaningful fat reduction and supporting weight loss goals over months of use for appropriate candidates.


Examining pooled evidence from controlled studies testing Ozempic also demonstrates its abilities to assist with weight loss objectives when combined with implementing health-focused lifestyle adjustments.

Participants in the studies who embraced new eating habits and increased their physical activity while using Ozempic once a week found a significant part of their journey reflected in a 14.9% reduction in excess body weight over 68 weeks, showcasing the power of combined efforts.

So clinical trial data supports Ozempic, too, as a useful accompaniment for motivating significant slimming and weight reduction over an extended period when used together with establishing healthy daily eating and exercise habits.

Winner: Mounjaro

Clinical data suggests higher average weight loss percentages among Mounjaro users compared to Ozempic.

Mounjaro vs Ozempic: How to Use Each Medicine


Mounjaro comes in a prefilled, disposable injection pen already containing the medication. Patients inject it themselves under the skin once every 7 days.

The pen has a thin needle you press to release the medication into fatty tissue in areas like your stomach, thighs or arms. The process is designed to be simple for anyone to perform themselves at home without special skills.

Most people start at 2.5mg weekly. After the first month, your doctor may slowly increase your dose up to a maximum of 15mg per week over time, depending on your needs and results. This gradual dose escalation allows your body to adjust while enabling increasing weight benefits.

The injection pen must be refrigerated until taken out 30 minutes before use. Once injected, the capped needle should be carefully thrown away in a sealed container to avoid injury or illegal reuse.


Like Mounjaro, Ozempic also utilises prefilled injection pens already containing the once-weekly doses. You self-administer the medication under the skin following clear instructions.

The dose usually starts lower at just 0.25 or 0.5mg weekly for the first month. Later, the amount may be raised in increments, if needed, to a maximum of 2mg as prescribed by your healthcare provider based on monitoring of your health reactions and weight loss responsiveness.

As with Mounjaro’s pen injector, refrigerated storage is needed but once in use, you can store them for up to 6 weeks at temperatures below 30 °C. Safe disposal into approved containers happens immediately after to avoid contamination or misuse.

Winner: Draw

Both Ozempic and Mounjaro utilise injectable pens designed for simplicity and ease of use, aiming to minimise patient inconvenience. Without significant differences in the administration method that would clearly favour one over the other, the choice largely depends on individual preferences and specific medical advice.

Mounjaro vs Ozempic: Side Effects and Safety


Like most medications, Mounjaro can cause some adverse effects in some users. However, most are mild and temporary, especially as your body adjusts during the first month.

The most common stomach side effects include diarrhoea, indigestion, vomiting, constipation or abdominal pain. However, you could also experience nausea or decreased appetite. These usually peak early on and resolve during the treatment.

In rare cases, more severe adverse reactions like inflammation of the pancreas or gallbladder disease are possible. Allergic reactions can also happen rarely.

Overall, though, Mounjaro displayed a strong safety profile in clinical trials with no new safety issues identified compared to other similar diabetes medications.

It does carry a warning about possible thyroid tumours, but this stems from lab studies in rats using much higher doses. To date, testing has uncovered no increased thyroid cancer risk in the actual use in humans, even after many years. But longer-term real-world monitoring continues.


As with most drugs, Ozempic can also sometimes produce common side effects in users. Typically, these are temporary and mild until your body regulates.

The most frequent symptoms include nausea, vomiting, diarrhoea, decreased appetite, indigestion, constipation, abdominal discomfort and fatigue early after starting injections.

Rarely, complications like gallbladder disease, severe inflammation of the pancreas, vision changes or kidney injury are possible. Allergic reactions can also uncommonly occur.

But overall, clinical studies report Ozempic seems well tolerated without any unforeseen safety issues appearing compared to other GLP-1 receptor agonists (a type of treatment designed to mimic a natural hormone in your body that regulates blood sugar and appetite) used long term.

As with Mounjaro, there is also a warning about theoretical thyroid cancer risk due to lab rat studies. But medical consensus to date confirms no actual increased thyroid tumour rates in humans prescribed Ozempic so far, including no elevated occurrences after several years of use. Regardless, patient monitoring continues as a precaution.

Winner: Draw

Both medications have their unique side effects and safety profiles. The choice depends on individual health conditions and tolerance for specific side effects.

Mounjaro vs Ozempic: Who Can Use Each Medication

General Eligibility

In general, prescription weight loss medications like Mounjaro and Ozempic may be an option for adults struggling with obesity, which is defined by health organisations as having a body mass index or BMI over 30.

Your doctor will calculate your BMI using your weight and height to see if you fall into the obesity range. If so, they may consider a drug like Mounjaro or Ozempic as an addition to diet, exercise and behavioural changes to help you shed excess pounds for better health.

Of course, these injectables are not right for everyone working to lower weight. Your physician will conduct required health screenings to ensure you are an appropriate candidate without major risks, given your full medical history and current medical conditions.


Since approved for chronic weight management, Mounjaro can be prescribed to patients with:

  • Obesity is defined by a BMI over 30 plus at least one weight-related health problem such as high blood pressure, cholesterol issues, sleep apnea or osteoarthritis
  • No past history of certain health problems that could be made worse by the drug, such as thyroid, pancreatic or gallbladder disorders

If you’ve been facing challenges with obesity and its complications, know that it’s okay to ask for help. Your doctor can consider if Mounjaro might be a supportive option for you, ensuring your safety and well-being throughout the process.


Since Ozempic is only indicated for blood sugar control in type 2 diabetes - not specifically weight loss - you should not have access to Ozempic for the purpose of shedding some pounds.

Still, research shows it can lower weight as a side effect benefit.

As with any drug, your physician must determine if Ozempic suits your situation through needed checks into your fitness and history.

Winner: Mounjaro

Mounjaro has the official approval for weight loss, making it accessible to a wider audience for this specific purpose.

Mounjaro vs Ozempic: Which Is Better for Weight Loss?

When comparing Mounjaro and Ozempic specifically for weight loss effects, there are some similarities but also key differences to understand.

Both are injectable weight loss drugs requiring a prescription and consistent use over weeks/months for increasing impact. As with any drug for obesity, they need to be paired with positive diet changes and added physical activity for optimum results.

Research shows both options can facilitate weight reduction to varying extents. They also have low risks of mostly temporary side effects in some patients.

However, a few major distinctions exist. The clinical trial data so far demonstrates that Mounjaro generates slightly greater average pounds lost in head-to-head studies with obese and overweight adults.

Additionally, Mounjaro has already received a full UK regulatory green light for prescribing specifically for chronic weight management purposes. Ozempic remains sanctioned primarily for diabetes blood sugar control instead.

Overall, both medications may offer obesity treatment benefits to the right candidates. However, individuals facing weight issues without diabetes may wish to explore if the newly approved Mounjaro proves a better fit, pending health policy choices for unmet weight management needs.

Take the Next Step With The Independent Pharmacy

Meeting with a doctor to decide if any medication coupled with lifestyle changes makes sense specifically for you and your health is critical.

As an accessible online pharmacy and private prescription facilitator, The Independent Pharmacy delivers customised weight management assistance through licensed UK clinicians.

You can easily begin with our free online assessment outlining your background and goals. Our experts then privately evaluate your details to recommend evidence-based treatment ideas matched to you as an individual.

Suggestions may cover nutrition adjustments, increased activity, additional behavioural changes and, if suitable, prescription weight management options they provide, such as Orlos, Orlistat, Alli or Xenical. Regular progress tracking provides ongoing support.

Reach out to The Independent Pharmacy to affordably discuss in confidence personalised solutions for achieving realistic weight aims and lowering obesity disease risks.


Does Mounjaro work better than Ozempic?

Yes, in clinical trial comparisons so far, Mounjaro has produced greater average weight loss than Ozempic.

How quickly do you lose weight on Mounjaro?

Users tend to see meaningful weight loss kicking in within the first 4 months. Gradual dose increases over time lead to accumulating further improvements with maximum impact closer to 1 year.

What is stronger than Ozempic?

The medication clinical trial data shows as more potent than Ozempic for weight loss at present is Mounjaro. Discuss with your doctor if it may be a useful alternative if Ozempic alone has not provided enough weight reduction effects for your aims.


European Medicines Agency (2022). Mounjaro (tirzepatide) -

Mark M. Smits and Daniël H. Van Raalte (2021). Safety of Semaglutide -

Vivek P. Chavda, Jinal Ajabiya, Divya Teli, Joanna Bojarska, and Vasso Apostolopoulos (2022). Tirzepatide, a New Era of Dual-Targeted Treatment for Diabetes and Obesity: A Mini-Review -

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