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Mounjaro vs Ozempic

Robbie Puddick
Written by

Robbie Puddick

Medically reviewed by

Fiona Moncrieff

8 min read
Last updated June 2024

Jump to: How do Mounjaro and Ozempic work? | Do you lose more weight on Mounjaro or Ozempic? | Mounjaro vs Ozempic: Which one should you choose? | Take home message

Mounjaro and Ozempic are GLP-1 receptor agonists, a class of medications that mimic the hormone GLP-1 to support weight loss and lower blood sugar levels.

Second Nature launched a Mounjaro weight-loss programme in February 2024 designed to help you build healthy habits while the medication supports consistent weight loss.

Mounjaro, in addition to mimicking GLP-1, also mimics GIP, another hormone in the body that lowers hunger to support weight loss.

So, Mounjaro has a dual function that mimics two hormones that lower hunger, support weight loss, and lower blood sugar levels.

Ozempic is manufactured by Novo Nordisk, while Mounjaro is by Eli Lilly. The active ingredient in Mounjaro is tirzepatide, and semaglutide in Ozempic.

Based on data from a randomised controlled trial, Mounjaro is generally more effective for weight loss than Ozempic.

However, studies have shown that Ozempic generally has a better safety profile than Mounjaro, with more people stopping Mounjaro due to side effects and other adverse events.

So, if you’re looking for a medication to help you lose weight and improve your blood sugar levels, Mounjaro will lead to more weight loss and blood sugar reductions. Still, you might be more likely to tolerate Ozempic and stay on the medication.

However, individual responses to medications vary between individuals. Be mindful of side effects and contact your healthcare team to determine the appropriate medication and dosage.

Mounjaro and Ozempic are approved for individuals living with type 2 diabetes in the U.S., while Mounjaro is also approved for weight loss in the UK.

They were initially approved as prescription drugs but are now widely available online for private purchase.

Ozempic is available in the UK if you’re living with type 2 diabetes, and Mounjaro will be available from Second Nature by February 2024.

Both medications have similar dosing schedules and are administered once a week. The main difference is the amount of medication used. The volume of the doses with Mounjaro is larger than with Ozempic.

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Ozempic and Mounjaro dosing schedules

Mounjaro and Ozempic dosing schedules

Not a magic pill

These medications are designed as additional tools for weight management interventions and shouldn’t be considered lifelong medications.

Instead, they should be used to help you kickstart your weight loss and healthy journey while you commit to living a healthier lifestyle.

At Second Nature, we’ve been trusted by the NHS since 2017 to support people with type 2 diabetes and obesity to lose weight and manage their blood sugar levels and lead healthier lifestyles for the long term.

If you’re considering purchasing Mounjaro (when it’s available in the UK) or Ozempic but need support in making positive changes to your lifestyle, Second Nature could be an option for you.

In 2022, the NHS published data in the BMJ that compared the weight loss outcomes of five providers in the National Diabetes Prevention Programme.

Second Nature was more than twice as effective at supporting weight loss than the other four providers.

Second Nature Weight Loss NHS

1) How do Mounjaro and Ozempic work?

When we eat food, our gut releases hormones that help the body regulate hunger and blood sugar levels. One of these hormones is called GLP-1 (glucagon-like peptide-1).

GLP-1 improves insulin function to lower blood sugar levels and delay gastric emptying, decreasing appetite.

GLP-1 also communicate with the brain’s appetite control centre, the hypothalamus, to lower food-seeking behaviour.

How Wegovy works for weight loss

However, GLP-1 is removed rapidly from the body by an enzyme called DPP-4. It’s been shown that up to 50% of the GLP-1 released from the gut after a meal is removed by DPP-4 within 2 minutes.

Mounjaro and Ozempic work because they’ve been manufactured to be resistant to DPP-4 and can stay in the body for much longer.

How Wegovy works for weight loss

In addition to these actions, Mounjaro also mimics a hormone called GIP, which shares many similarities with GLP-1.

GIP is a hormone released in response to food that helps regulate blood sugar levels and helps our fat cells ‘absorb’ more excess energy, preventing fat from being stored in the liver or pancreas.

GIP also has receptors in the brain, similar to GLP-1, and scientists believe it’s also involved in regulating appetite.

The dual actions of Mounjaro are one of the reasons that it generally leads to more weight loss than Ozempic.

Key points:

  • GLP-1 receptor agonists (GLP-1s) are a class of medications that mimic the actions of the hormone GLP-1, which helps regulate hunger and blood sugar levels
  • GLP-1s help the pancreas release more insulin, delay stomach emptying, and reduce appetite
  • GIP mimetics mimic the action of the hormone GIP, which improves insulin secretion to lower blood glucose and helps the body store fat in the adipose tissue, protecting the internal organs from excess energy storage

2) Do you lose more weight on Mounjaro or Ozempic?

Mounjaro leads to more weight loss than Ozempic after 40 weeks. Research showed the higher dose (15 mg) of Mounjaro led to nearly twice the amount of weight loss than Ozempic 1 mg.

A randomised controlled trial in 1,897 individuals living with type 2 diabetes compared the impact of three doses of tirzepatide (5mg, 10mg, and 15mg) compared to a once-weekly injection of 1mg semaglutide (Ozempic) on blood sugar levels.

The results showed that all three doses of tirzepatide led to more significant weight loss than 1mg of semaglutide.

Mounjaro leads to more weight loss than Ozempic.

Which is better for HbA1c, Mounjaro or Ozempic?

The hormone GLP-1 binds to GLP-1 receptors in the pancreas to increase insulin release after a meal. It also prevents the body from releasing too much glucagon, a hormone that increases blood sugar levels.

These two mechanisms support individuals living with type 2 diabetes in managing their blood glucose levels on a meal-to-meal basis.

Research has shown that GLP-1s are effective at reducing blood glucose for people living with type 2 diabetes.

Liraglutide (Saxenda) was one of the earlier forms of longer-lasting GLP-1s and reduces HbA1c (average blood glucose) levels by around 1.3% on average and fasting plasma glucose by 2 mmol/L.

In comparison, semaglutide (Ozempic) reduces HbA1c by around 1.8% on average and fasting plasma glucose by 2.8mmol/L.

Semaglutide (Ozempic/Wegovy) is more effective at reducing blood sugar levels than liraglutide (Saxenda). Interestingly, a new version of GLP-1s known as tirzepatide (Mounjaro) may be more effective than semaglutide.

Tirzepatide is a dual-action type 2 diabetes medication. Alongside its effects on GLP-1, it also mimics the actions of another hormone called GIP (gastric inhibitory polypeptide) that reduces blood sugar levels.

A randomised controlled trial in 1,897 individuals living with type 2 diabetes compared the impact of three doses of tirzepatide (5mg, 10mg, and 15mg) to a once-weekly injection of 1mg semaglutide (Ozempic) on blood sugar levels.

The results showed that all three doses of tirzepatide led to more significant HbA1c reductions than 1mg of semaglutide.

So, GLP-1 receptor agonists significantly reduce blood sugar levels and are an effective treatment for type 2 diabetes—particularly the longer-lasting and recent versions of GLP-1s, semaglutide and tirzepatide.

Interestingly, the lasting effect of GLP-1s to support type 2 diabetes might be its impact on reducing appetite and supporting weight loss rather than the impact it has on the pancreas.

Key points:

  • GLP-1 hormone increases insulin release after a meal and prevents the release of too much glucagon, helping manage blood glucose levels in individuals with type 2 diabetes
  • GLP-1 receptor agonists, particularly longer-lasting semaglutide and newer tirzepatide, are effective in reducing blood sugar levels.
  • Tirzepatide is a dual-action medication that mimics the actions of GIP, reducing blood sugar levels further
  • GLP-1s also reduce appetite and support significant weight loss of more than 10%, which is associated with reduced complications of obesity
  • Lifestyle interventions with semaglutide lead to 47% more people losing more than 10% of body weight compared to lifestyle interventions alone
  • Tirzepatide appears more effective than semaglutide in reducing both blood sugar levels and weight

3) Mounjaro vs Ozempic: Which one should you choose?


Mounjaro is a more effective drug than Ozempic. As demonstrated above, tirzepatide (the active ingredient in Mounjaro) leads to more clinically significant weight loss and blood sugar reductions than semaglutide (the active ingredient in Ozempic).

So, if you were looking at trying GLP-1 medications for weight loss or blood sugar improvements, Mounjaro would be the better choice.

However, the drugs differ in their side effects and safety profiles which might influence your decision.

Side effects and safety

All medications have possible side effects, particularly if you live with other health conditions. 

Some will be mild but uncomfortable, such as cramping, and others will be more severe, such as shortness of breath. You must report any side effects you experience to your doctor and healthcare team when on medications.

In a randomised controlled trial with over 1,800 participants comparing tirzepatide to semaglutide, the tirzepatide group reported more serious adverse events (5-7% VS 3%) and higher discontinuation rates due to adverse events (6-8.5% VS 4%). 

Additionally, there were more deaths in the tirzepatide group than in semaglutide (12 vs 1). However, the researchers confirmed they didn’t believe these deaths were linked to the medication.


Mounjaro cost

Mounjaro will cost £230-£300 a month with Second Nature when it becomes available in 2024.

A Mounjaro prescription via the NHS would cost the standard base fee of £9.95.

Ozempic cost

The cost depends on where you’re purchasing it from and how long you intend to use the medication.

However, to purchase the medication and injectable pens required for four weeks would likely cost around £300.

In the U.S., the cost will depend on your insurance coverage, any discounts available, and your pharmacy. Typically, it will start at a lower cost of around $25 a month and rise after 6 months to around $1500.

Key points:

  • Mounjaro is more effective than Ozempic at supporting weight loss and blood sugar reductions
  • However, Ozempic seems to lead to fewer side effects and is better tolerated than Mounjaro
  • However, individuals will vary in their medication response, so choose the right one for you
  • Both medications are expensive if you opt to purchase them privately

Take home message

Weight-loss injections are most effective when combined with a healthier lifestyle. They can help kickstart weight loss while you commit to developing healthier habits.

Mounjaro and other weight loss injections, like Ozempic and Wegovy, can allow you to make lifestyle changes to support long-term weight loss.

These medications can help silence food-related thoughts and give you a boost of confidence with more immediate weight-loss results.

They can also buy you the time and headspace to understand why your body may have struggled to lose weight previously and to build new long-term healthy habits.

The core focus of our medication programmes is to calm down the feeling of food noise, lower your cravings, and allow you to build healthier habits to keep the weight off for good.

The ultimate goal is to make losing weight feel second nature.

Second Nature’s medication programmes

Second Nature has two medication-supported programmes: a Wegovy weight-loss programme and a Mounjaro weight-loss programme.

If you’ve made the decision to try Wegovy or Mounjaro (assuming you’re eligible), why should you choose Second Nature over other medication providers?

For peace of mind.

Second Nature has worked with the NHS for over 6 years, providing weight-loss programmes across the UK.

Whilst our Wegovy and Mounjaro weight-loss programmes are private and not currently used by the NHS, we’ve built the programmes focusing on scientific evidence, patient safety, and data security.

We hope that our 6+ years of working with the NHS and building a track record of effective weight-loss results will give you peace of mind to give us a try.

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Write a response

Evelyn M Taylor-humphrey

30 October, 2023

What is my. Starting dose for Monjaro, I’ve currently use Ozempic at 2mg.?

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