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Mounjaro vs Trulicity

Robbie Puddick
Written by

Robbie Puddick

Medically reviewed by

Fiona Moncrieff

7 min read
Last updated May 2024

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

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

Trulicity and Mounjaro are manufactured by the pharmaceutical company Eli Lilly. The active ingredient in Mounjaro is tirzepatide, and dulaglutide in Trulicity.

Mounjaro and Trulicity 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.

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

According to data from randomised controlled trials, Mounjaro is generally more effective than Trulicity for weight loss and blood sugar improvements.

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.

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.

Trulicity 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.

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 Trulicity.

Moujaro and Trulicity dosing schedules:

Mounjaro and Trulicity 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 trusted 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 Trulicity 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 Data

1) How do Mounjaro and Trulicity 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 to lower blood sugar levels and delays gastric emptying, decreasing appetite.

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

Trulicity 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. Trulicity, in comparison, is a single-action type 2 diabetes injection.

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
  • Trulicity 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 Trulicity: Which is better for weight loss?

Mounjaro (tirzepatide) leads to more significant weight loss than Trulicity (dulaglutide).

However, it’s worth noting that Trulicity isn’t approved for weight loss in the UK but only for people living with type 2 diabetes.

A randomised controlled trial in 636 adults compared the impact of Mounjaro to Trulicity on weight loss and blood sugar after one year.

The results showed that all three doses of Mounjaro (5mg, 10mg, and 15mg) led to more significant weight loss than Trulicity.

Participants on 5mg of Mounjaro lost 7.8% of their weight, those on 10mg lost 11%, and those on 15mg lost 13.9%. In comparison, participants on Trulicity lost less than 1% of their body weight on average.

Other trials on Trulicity have shown similar results on weight loss of around 1-2%.

Mounjaro vs Trulicity: Which is better for HbA1c?

The study in 636 participants mentioned above also measured the impact of Mounjaro and Trulicty on blood sugar improvements, or HbA1c, a test that measures average blood sugar (or blood glucose) levels over the past 90 days or so.

All three doses of Mounjaro were more than twice as effective at lowering HbA1c than Trulicity after one year.

So, Mounjaro is a more effective medication than Trulicity for supporting weight loss and blood sugar improvement.

Key points:

  • The highest dose of Mounjaro leads to a weight loss of around 13% after one year, whereas Trulicity has a minimal impact on weight loss, and patients average around 1% of weight loss
  • The three doses of Mounjaro are all around twice as effective at lowering HbA1c (blood sugar) than Trulicity
  • Mounjaro is a more effective type 2 diabetes and weight-loss injection than Trulicity

3) Mounjaro vs. Trulicity: Which is better?


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

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 profile, 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.

A study comparing Mounjaro to Trulicity found that nausea was the most common side effect of both medications.

However, only 8% of participants on Trulicity reported nausea compared to 12% on Mounjaro 5mg and 20% on Mounjaro 10mg and 15mg.

Other side effects including constipation were reported at similar rates in the Mounjaro and Trulicity participants.



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.


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 cost around £126, or around £1520 per year.

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

Key points:

  • Mounjaro is more effective than Trulicity at supporting weight loss and blood sugar reductions
  • However, Trulicity may lead to less feelings of nausea than Mounjaro. Overall, the safety profile of both medications is similar, and the most common side effects are GI-related, like constipation.
  • However, individuals will vary in their medication response, so choose the right one for you
  • Trulicity 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

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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