Mounjaro Maintenance and Gut Health

Posted on September 30, 2026 by Sally-Anne Turner

Are you worried about starting GLP-1s due to a gastrointestinal issue?

At the time of writing, the Inflammatory Bowel Disease UK website notes that as many as half a million people in the UK are diagnosed with an inflammatory bowel condition. All GLP-1s are known to cause stomach issues, meaning they can cause more than a bit of a sore tummy if you already have a problem with your stomach. This is even the case with injections, like Mounjaro.

Does this mean you shouldn’t take GLP-1s? No. However, you may need additional clinical support and a personalised Mounjaro maintenance plan to help manage gastrointestinal symptoms throughout your weight-loss treatment.

When you work with our team at the Bodyline Clinic, our dedicated clinical team will take the time to assess any secondary conditions that you may have, which may require the oversight of our specialised support team. We know that, for many, GLP-1’s point to more than simply wanting to shed a few pounds. So, we won’t reject you for treatment with any of our GLP-1s until we have a complete clinical picture.

Here, we will run through Mounjaro, how it may impact any gastrointestinal issues and how our clinical team can support you on your weight loss journey.

What is Mounjaro?

A quick recap first.

Mounjaro is a GLP-1 GIP medication, which is prescribed in the UK for the treatment of type 2 diabetes and weight management in adults who are obese (BMI ≥30 kg/m°) or overweight (BMI ≥27 kg/m°) with at least one weight-related comorbidity.

It is injected once a week under the skin and mimics both the glucagon-like peptide hormone (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). This helps you feel full for longer and also helps to reduce food noise. When targeted at the same time, these show benefits in those who have type 2 diabetes and also result in weight loss.

This injection is usually started at a low dose of 2.5mg per week. It is then titrated upwards to help minimise gastrointestinal side effects. Mounjaro can be injected under the skin of your abdomen, thigh or upper arm. There isn’t one best place to inject Mounjaro for weight loss, so you should follow the injection instructions provided with your medication and rotate your injection sites.

According to Crohn’s and Colitis UK, as many as 40% of people who have Crohn’s disease or IBD/IBS are also overweight or obese. This poses an interesting challenge for both patients and clinical teams: how do you manage these conditions when taking GLP-1 injections for weight loss?

How Mounjaro Impacts the Stomach

A core part of why GLP-1 medications impact the stomach is because of gastroparesis. This is sometimes called stomach paralysis, and this is why the process of taking a weight loss medication can be so uncomfortable.

Some of the most commonly reported gastrointestinal side effects include:

1. Mounjaro nausea and vomiting
2. Mounjaro diarrhoea
3. Mounjaro constipation
4. Stomach pain and cramping

This can make treatment more complicated for someone with an existing gastrointestinal condition, because Mounjaro diarrhoea, constipation and abdominal discomfort can overlap with the symptoms of a Crohn’s disease flare, which, according to the NHS, including:

1. Diarrhoea
2. Blood or mucus in your stool
3. Stomach pain
4. Constipation
5. Pain in your bottom (anus)
6. Feeling tired or unwell
7. Loss of appetite and losing weight.

As you can see, quite the overlap! So, to prevent a worsening of the side effects, there are some things you can do. You can aim to take Mounjaro at bedtime so that nausea is less likely to disrupt your sleep.

For runny or loose stools, aim to increase your fluid intake to prevent dehydration. We have a guide on what to eat when using GLP-1s, which you can see here.

Best Foods to Reduce Side Effects

The nature of Crohn’s and other IBD is that someone who is diagnosed with these conditions will likely have sporadic attacks. There are some triggers which can cause a flare, such as smoking or even genetics.

So, when taking GLP-1s, which are more likely to aggravate these conditions, what should be eaten to keep these conditions at bay?

1. Disease is Inactive/Settled: Aim to eat a varied diet. Get your protein from eggs, fish, chicken and yoghurt. Also eat fruit, veg and fibre that you can tolerate.
2. Nausea or early fullness after a GLP-1 dose: Aim to eat smaller meals more regularly. Eat slowly, stop when full and see if greasy meals worsen nausea. Try eggs on toast, bananas, chicken and rice. Don’t forget the veg!
3. A flare with diarrhoea: Consume fluids and eat softer options, such as peeled and well-cooked vegetables. Try the BRAT diet. If you need oral rehydration solutions, seek clinical guidance relating to GLP-1medications.
4. A known stricture or previous blockage: Follow your gastroenterologist’s advice. Our team at the Bodyline Clinic will work with them to ensure your weight loss treatment is safe and as comfortable as possible.

These food choices were obtained from Crohn’s and Colitis UK and the NHS. Of course, our team will assess your Crohn’s disease severity and work with you to construct a diet plan that ensures safety and reduces the symptoms of Crohn’s or IBD.

Crohn’s, IBD and Mounjaro: The Clinical Side

We at the Bodyline Clinic are big on research into the conditions we provide specialised care for. You may have read in online Mounjaro reviews or seen on social media that this GLP-1 is linked to all kinds of worsening GI disorders.

So, what does the data say about Mounjaro and Crohn’s or other IBD’s?

A study conducted in 2025 by the Mayo Clinic looked at 29 people with Crohn’s or ulcerative colitis (they were grouped). This group was compared to 58 people without an IBD. Those who were in the IBD group reported higher levels:

1. Nausea or vomiting (41% versus 10%).
2. Abdominal pain (20% versus 3%).

Also, this piece is, to date, a conference abstract. Thus, any finding from it requires a cautious interpretation.

There have been other studies which have explored GLP-1 medications as a group. One that was published in 2025 in the Inflammatory Bowel Disease Journal noted that there was no increase in IBD, but it needs to be stated that tirzepatide does not relieve Crohn’s symptoms. However, these studies looked at the prescribing of steroids or admissions to hospital as a measure of a Crohn’s flare. They did not track day-to-day symptoms.

What Bodyline Will Assess

If you have been diagnosed with Crohn’s or any other irritable bowel condition, you will need to disclose this to us (or your clinical team) as well as your GP before starting Mounjaro. We will need to assess the benefits of taking GLP-1s to see if they outweigh the risks that may present with gastrointestinal issues.

We will usually ask you about:

1. Your Crohn’s disease history: We will ask you about the severity of your Crohn’s disease. This will include recent flares, any current symptoms you are having and complications such as strictures or any fistulas. We will also ask you if your Crohn’s is in remission or active. This will determine the timing to start your treatment, if at all.
2. Current medications: We will ask you about the medications you are taking. For Crohn’s, or other IBD, this may include immunosuppressants, biologics (including injectables), steroids or over-the-counter supplements. We will need to consider drug interactions, especially if you are taking insulin or other agents that lower glucose.
3. Contraception, pregnancy and breastfeeding: We have written about GLP-1s and pregnancy. Tirzepatide is not recommended during pregnancy or breastfeeding. Mounjaro, like orforglipron (Foundayo), may also reduce the impact of some oral contraceptives. So, you may need to use additional barrier contraception for 4 weeks after starting Mounjaro, as well as after each dose increase.
4. Your Weight Management Goals: We will ask you why you may want to consider Mounjaro, and we will discuss your expectations. We will assess if it is clinically appropriate and whether we may be able to offer other GLP-1s, which may be safer based on your Crohn’s disease or IBD.
5. Monitoring and follow-up: Our team will also establish a treatment plan for monitoring your weight loss goals alongside checking your Crohn’s disease activity. We may recommend blood tests (to check for inflammation markers), symptom diaries and schedule follow-ups with our team, your GP or your gastroenterologist.

We always advise patients to seek urgent advice if you experience abdominal pain, persistent vomiting, blood in stools or any symptoms that point to a Crohn’s flare or a drug reaction. You should also seek immediate medical attention if you notice severe, persistent, upper abdominal pain (that may radiate up your back). You may also experience vomiting, fever and a rapid heart rate. These can point to pancreatitis, which, while rare, has been noted with Mounjaro in the SURPASS 2 and SURMOUNT 1 trials, ranging from 0.22–0.39%.

Why Choose Bodyline?

When you want to lose weight, it is not as simple as exercising more and eating less. Our team at the Bodyline Clinic knows this.

We also take the time to get to know everyone that we work with relating to GLP-1weight loss. Our clinical team aims to help people who may have been excluded from pharmacies or online providers, offering personalised clinical support and individualised Mounjaro maintenance plans. If gastrointestinal symptoms become difficult to manage, we can review your treatment, side effects and titration schedule rather than taking a one-size-fits-all approach.

Indeed, we specialise in helping those who have:

1. Been diagnosed with mental health issues.
2. A history of cardiovascular issues.
3. Gastrointestinal issues.

We also aim to help people who are over the age of 75. All of these groups are often excluded from GLP-1 research, so there is limited data on how it may impact them as a group. However, we can assess side effects, secondary health conditions and weight loss to keep you safe and healthy while you hit your goal weight. We will also adjust doses or titration plans based on your reactions, putting your health first.

So, if you have a condition like Crohn’s disease, or another IBD and want to lose weight with a GLP-1, please contact our team today for a consultation.

FAQs

How many calories do you eat on Mounjaro?

There is no universal calorie target that each person taking Mounjaro needs to hit. Your daily intake will vary based on your age and health. Body size, activity levels and your weight loss goals. Mounjaro does need to be taken alongside a reduced-calorie but nutritionally balanced diet. Our team will help to determine which kind of support and diet is needed to help hit all of those goals, while also ensuring you lose weight.

Does Mounjaro make you lose weight or just suppress appetite?

Mounjaro supports weight loss by both reducing your appetite and helping you to feel fuller for longer. This makes it easier to eat fewer calories. The active ingredient is tirzepatide, which impacts both GIP and GLP-1 receptors. The weight loss occurs when both of these contribute to a prolonged reduction in energy intake.

Is there a tablet form of Mounjaro?

In a word, no. The same pharmaceutical team behind Mounjaro also made the recently released Foundayo, but they are not the same medication. If you see an advert online for an “oral Mounjaro,” it’s a scam!