Second Nature logo



Why am I not losing weight on Mounjaro?

Robbie Puddick
Written by

Robbie Puddick

Medically reviewed by

Fiona Moncrieff

6 min read
Last updated June 2024

Jump to: How do you maximise weight loss on Mounjaro? | 1 – You’re not eating in a calorie deficit | 2 – You’ve hit a temporary weight-loss plateau | 3 – Your current dose isn’t high enough to promote lower hunger

The top 3 reasons why you’re not losing weight on Mounjaro might be that:

  1. You’re not eating in a calorie deficit
  2. You’ve hit a temporary weight-loss plateau
  3. The current dose that you’re on isn’t high enough to lower your hunger to the point where you’re eating less

Not everyone responds the same way to Mounjaro (tirzepatide), and other factors may also contribute to a pause in weight loss, such as other medications or health conditions impacting our ability to lose weight.

It’s also important to note that the clinical trials of Mounjaro were run where the participants were undergoing lifestyle change i.e. improving their nutrition, exercise, and sleep.

To maximise your weight-loss results and also improve your health, it’s important to focus on creating new healthy habits while you’re taking Mounjaro. To the extent that we’d say: there’s no point taking Mounjaro unless you also change your habits.

Creating new habits, alongside taking Mounjaro, is the main focus of our Mounjaro weight-loss programme. To check your eligibility and sign up for Mounjaro, you firstly need to complete our health quiz.

Check my eligibility

How do you maximise weight loss on Mounjaro?

To maximise weight loss on Mounjaro, it’s essential to make positive changes to your diet and lifestyle.

Mounjaro is only approved for weight loss as an aid to be used alongside lifestyle improvements. So, there’s no evidence that Mounjaro can work sustainably in the long term without us also eating a healthy diet, getting active, and improving our emotional health.

Now, keep reading as we dig deeper into the three reasons you’re not losing weight on Mounjaro.

1) You’re not eating in a calorie deficit

The evidence is clear: we must eat within a calorie deficit to lose excess body fat. When we eat below our energy balance, our body has to find the energy required to fuel our body’s primary functions by burning excess fat.

Mounjaro works by interacting with the brain’s appetite control centre, the hypothalamus, to lower hunger and food-seeking behaviours.

Research suggests that Mounjaro can reduce our energy intake by around 31% compared to individuals not taking Mounjaro.

However, we eat for more reasons than physical hunger, and some people might continue to eat enough food that prevents them from achieving a calorie deficit due to psychological, environmental, or habitual reasons.

Additionally, suppose our baseline diet was rich in ultra-processed foods and refined sugars, and we continue to eat this way whilst on Mounjaro. In that case, we may still eat more calories than we need to lose weight.

So, it’s essential we transition to a diet based on whole foods to maximise the results of Mounjaro.

Key points:

  • We need to eat in a calorie deficit to lose weight
  • If our baseline diet is rich in ultra-processed foods and we continue to eat this way on Mounjaro, we may still consume more calories than we need to lose weight
  • It’s essential to eat a diet based on whole foods to support sustainable weight loss

2) You’ve hit a temporary weight-loss plateau

Suppose we’ve lost some weight on Mounjaro, but then we hit a plateau, and we can’t budge the scales any more. In this case, we’re likely in a weight-loss plateau.

Weight-loss plateaus are extremely common, normal, and a necessary part of the weight-loss process. Being on Mounjaro doesn’t prevent us from experiencing weight-loss plateaus.

We have a full guide explaining weight-loss plateaus. However, as a quick summary:

  • Our brain receives signals from many hormones, letting it know how much energy we’re eating and how much fat we have stored. We call this the brain’s ‘set point’.
  • Weight-loss plateaus occur when our brain senses that we’re consuming fewer calories than normal and our fat stores are decreasing it ‘slows down’ our metabolism
  • Evolutionarily, we’re wired to protect fat to ensure survival
  • So, weight-loss plateaus are a survival mechanism in the brain to try and protect us from starvation
  • Fortunately, we can gradually lower our brain’s set point by continuing to lead a healthy lifestyle and being consistent in our habits

Key points:

  • Weight-loss plateaus are a necessary and normal part of the weight-loss process. Mounjaro doesn’t prevent weight-loss plateaus from occurring.
  • Weight-loss plateaus occur when our brain senses we’re losing fat and eating less, so it slows down our metabolism to protect our remaining fat stores
  • We can overcome weight-loss plateaus by being consistent with our healthy habits

3) Your current dose isn’t high enough to promote lower hunger

Mounjaro reduces appetite and hunger, helping you eat fewer calories; this effect is almost immediate when you start Mounjaro

However, you might notice the effect of lower hunger wearing off after 4-5 days post-injection in the first month of taking Mounjaro.

It can take 4-5 weeks for Mounjaro to reach a level in the body we call a steady state. A steady state is when the drug’s levels in the body remain consistent rather than spiking and falling.

Interestingly, this initial weight loss is no different to other weight loss treatments or the impact of diet interventions on weight loss. The real effect of Mounjaro is seen beyond three months.

Mounjaro is a long-acting medication that’s started at a lower dose to reduce the number and severity of side effects as it’s built up to a higher maintenance dose.

Additionally, we might find that our body adapts to the lower doses, and hunger can increase. However, we might find this reverses when we move up a dose.

Key points:

  • The lower doses of Mounjaro can wear off after 4-5 days
  • It can take up to 4-5 weeks for the medication to reach a ‘steady state’ where its levels are consistent in the blood
  • Weight loss may be steady at the beginning but become more consistent as you increase your dose

Not a magic pill

Weight-loss injections 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.

Consider the use of antidepressants for people living with depression. They’re not designed to cure the condition. Instead, they’re designed to allow room for therapy to treat the condition’s underlying cause.

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

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

This helps to 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-supported 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 with a focus 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.

Meal Plan

Maximise your weight loss on Wegovy/Mounjaro with our free 7-day meal plan

Get expert advice from our team of registered dietitians to make losing weight feel easier while on medication. Subscribe to our newsletter to get access today.

I've read and agreed to the Terms of Service & Privacy Policy.

You might also like

Make losing weight feel Second Nature

The first step on your Second Nature journey is to take our health quiz.

Hand holding phone

Write a response

Sunny Lynn

1 May, 2024

I’m not losing weight on Mounjaro and I was wondering if Ozempic would work better for me?

Mike Gibbs

7 May, 2024

Hi Lynn – if you’re in the UK then unfortunately Ozempic is not available for weight loss. Wegovy is available for weight loss, and uses the same underlying drug (semaglutide).

It would be very difficult for us to say whether Wegovy would work better for you, without knowing your medical history and experience with Mounjaro. It may be the case that Mounjaro is having an effect but you might need to make some further adjustments to your lifestyle habits to push through any weight-loss plateau that you’re experiencing. Also, occasional weight-loss plateaus are expected during a weight-loss process; it’s very rarely a linear journey.

As seen on

The GuardianThe TimesChannel 4The Sunday Telegraph
Evening Standard