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Mounjaro vs Rybelsus

Robbie Puddick
Written by

Robbie Puddick

Medically reviewed by

Fiona Moncrieff

8 min read
Last updated May 2024

Jump to: How do Mounjaro and Rybelsus work? | Mounjaro vs Rybelsus: Which is better for weight loss? | Mounjaro vs Rybelsus: Which is better? | Take home message

Mounjaro and Rybelsus are GLP-1 receptor agonists, medications that reduce appetite to support weight loss and improve blood glucose control through various mechanisms.

Mounjaro – in addition to being a GLP-1 medication – is also a glucose-dependent insulinotropic polypeptide (GIP) mimetic.

GIP is a hormone in the body that supports blood glucose levels and helps our fat cells store more excess energy we might consume in our diets.

GIP is also believed to lower hunger because GIP receptors are in the brain’s appetite control centre, the hypothalamus, similar to GLP-1.

So, Mounjaro has a dual function that mimics two hormones in the body that support blood glucose levels and weight loss.

Rybelsus is manufactured by the pharmaceutical company Novo Nordisk, and Mounjaro by Eli Lilly. The active ingredient in Mounjaro is tirzepatide, and semaglutide in Rybelsus.

Based on data from randomised controlled trials, Mounjaro is generally more effective for weight loss and blood sugar improvements than Rybelsus.

So, if you’re looking for a medication to help you lose weight and improve your blood sugar levels, Mounjaro will likely lead to more weight loss and blood sugar reductions.

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

How do you get a Mounjaro or Rybelsus prescription?

Mounjaro and Rybelsus are medications approved for the treatment of individuals living with type 2 diabetes in the UK.

For the treatment of type 2 diabetes, Rhybelsus was approved in 2020, while Mounjaro was only approved in September 2023 as it’s a much newer medication.

Rhybelsus has never been approved for use in the treatment of obesity, while Mounjaro had it approved for obesity treatment in November 2023.

Rybelsus is available in the UK on prescription, while Mounjaro is likely to be available in early 2024 after being approved for type 2 diabetes in September 2023 and obesity in November 2023.

Rybelsus is an oral medication and is taken once daily, whereas Mounjaro is an injectable medication and is taken once weekly.

Rybelsus is available in three doses: 3mg, 7mg, and 14mg. Recent studies have investigated the effectiveness of higher doses of 25mg and 50mg. However, these doses aren’t yet available.

Mounjaro is available in doses ranging from 2.5 to 15mg, rising in 2.5mg increments.

Mounjaro and Rybelsus dosing schedules:

Mounjaro and Rybelsus dosing schedules

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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 used by the NHS since 2017 to support people with type 2 diabetes and obesity to lose weight, 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 Rybelsus 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.

1) How do Mounjaro and Rybelsus work?

When we eat food, our gut releases hormones that help the body regulate hunger and blood sugar levels.

GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) are two of these hormones.

GLP-1 improves insulin function, lowering blood sugar levels and delaying gastric emptying, decreasing appetite.

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

Rybelsus and Mounjaro mimic the actions of the hormone GLP-1 and are known as GLP-1 receptor agonists or GLP-1s.

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

GIP also communicates with the brain and is believed to lower hunger and food-seeking behaviour, similar to GLP-1.

Mounjaro, in addition to its function of mimicking GLP-1, also mimics the actions of GIP and is a dual-action type 2 diabetes and weight-loss injection. Rybelsus, in comparison, is a single-action type 2 diabetes medication.

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
  • Rybelsus is a single-action medication and mimics the hormone GLP-1
  • Mounjaro is a dual-action medication and mimics the hormones GLP-1 and GIP

2) Mounjaro vs Rybelsus: Which is better for weight loss?

Mounjaro (tirzepatide) leads to more significant weight loss than Rybelsus (oral semaglutide). However, it’s worth noting that Rybelsus isn’t approved for weight loss in the UK and is only approved for people living with type 2 diabetes.

Studies have yet to directly compare Mounjaro to Rybelsus to determine their impact on weight loss.

However, when looking at individual trials of both medications, it’s clear that Mounjaro significantly impacts weight loss.

A randomised controlled trial placed 2539 participants in one of four groups:

  1. Placebo
  2. Mounjaro 5mg
  3. Mounjaro 10mg
  4. Mounjaro 15mg

The results showed that all three doses of Mounjaro led to weight loss of greater than 16% of body weight after 72 weeks. The 15mg dose achieved a weight loss of 20.9% of body weight.

A randomised controlled trial on Rybelsus found that the 10mg dose led to a weight loss of just over 5% after 26 weeks of treatment. Other studies on Rybelsus have found similar results.

In the trial mentioned above, the 15mg dose of Mounjaro achieved 16% weight loss by 26 weeks, 11% more than Rybelsus.

Interestingly, researchers have been investigating higher doses of Rybelsus, up to 50mg per day, and found it can support weight loss of over 20% after 68 weeks.

These results suggest that the higher doses of Rybelsus can support similar weight loss to Mounjaro 15mg. However, Rybelsus is only approved in doses up to 14mg in the UK.

So, based on the currently available doses, Mounjaro is a more effective medication for weight loss than Rybelsus.

Mounjaro vs Rybelsus: Which is better for HbA1c?

Mounjaro and Rybelsus are approved for people living with type 2 diabetes in the UK. Like weight loss, Mounjaro is more effective at lowering HbA1c (blood sugar) than Rybelsus based on the currently available doses.

One study investigating the impact of Rybelsus on people living with type 2 diabetes found it reduced HbA1c by 1.4 percentage points, or around 15mmol/mol, after 26 weeks.

In comparison, research on Mounjaro has found that the 15 mg dose can reduce HbA1c by 2.5 percentage points, or around 28mmol/mol after 26 weeks.

So, Mounjaro 15mg can lead to a more significant reduction in HbA1c by around one percentage point or 13mmol/mol after 26 weeks.

Interestingly, 5mg and 10mg of Mounjaro also reduced blood sugar more than Rybelsus after 26 weeks.

Key points:

  • Research shows that the 15mg dose of Mounjaro leads to an 11% greater reduction in weight after 26 weeks than Rybelsus
  • All three doses of Mounjaro lead to more significant blood sugar reductions than Rybelsus
  • Mounjaro is a more effective type 2 diabetes and weight-loss injection than Rybelsus based on currently available doses

3) Mounjaro vs Rybelsus: Which is better?


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

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

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.

The side effect profiles of Mounjaro and Rybelsus are very similar.

The most common side effects in both medications are GI-related, such as nausea, diarrhoea, and vomiting, with around 20% of participants experiencing these side effects at least once and 60-75% of patients on these medications experiencing at least one adverse side effect.

One study showed that 3% of patients on Rybelsus experienced a severe adverse event linked to the medication, compared to 5.7% on Mounjaro.

Severe adverse effects are defined as those that interfere with daily activities, are generally intolerable, and lead to the cessation of the medication.


Mounjaro cost

Mounjaro will cost around £200-£300 a month from Second Nature when it becomes available. This price includes 1-1 support from a registered nutritionist to help you keep the weight off for good.

Getting Mounjaro on prescription through the NHS will cost the standard prescription fee of £9.95 in England.

Rybelsus cost

The cost depends on where you’re purchasing it from and how long you intend to use the medication. However, Rybelsus will cost £130-£190 per month.

Getting Rybelsus on prescription through the NHS will only cost you the prescription fee of £9.95 in England.

Key points:

  • Mounjaro is more effective than Rybelsus at supporting weight loss and blood sugar reductions
  • The safety profiles of both medications are fairly similar. The main side effects are GI-related, like nausea and constipation.
  • However, individuals will vary in their medication response, so choose the right one for you
  • Rybelsus is currently available in the UK
  • Mounjaro has been approved in the UK, but it’s not yet widely available
  • Both medications are expensive if you opt to purchase them privately
  • If you get them via the NHS, you’ll only have to pay the prescription fee of £9.95 in England

Take home message

The recent innovations in GLP-1 medications are pretty remarkable and have caused quite a stir in the world of healthcare.

We’re in new territory where obesity and type 2 diabetes medications treat an underlying cause instead of merely treating the symptoms to support better management.

However, these drugs shouldn’t be seen as miracle cures; they’re not designed to be used for life.

They’ve been designed to be taken alongside lifestyle changes that will enable you to eventually come off the medications and maintain your lower weight for the long term.

GLP-1s are safe and effective for most people in the short to medium term, but we don’t have long-term data to be sure they’re not causing severe adverse effects elsewhere.

At Second Nature, we’re not against using medications to support people in making healthy changes and reducing their risk of chronic disease.

However, we don’t recommend using medications as a reason not to make healthy lifestyle changes. The causes of obesity and type 2 diabetes aren’t merely rooted in biology but also psychology and sociology.

With these medications, you may lose weight and reduce blood sugar levels. But will you be happier? Will you be more fulfilled? Will you be content with your life and social relationships?

For that, you may need to consider a lifestyle change.

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