Ozempic and Gut Health: What You Need to Know Before You Start

Emma Mukasa | Registered Nutritionist
Sep 19
5 min read

Weight loss drugs like Ozempic are a hot topic at the moment. Despite being originally developed to manage obesity and type 2 diabetes, many people without these conditions are now turning to them for weight loss. Alongside Ozempic, other medications like Wegovy and Mounjaro (tirzepatide) are now widely available, each promising significant weight reduction with minimal effort. But as their popularity grows, so do the questions about their misuse and their impact on overall health.

Recent reports have linked GLP-1 medications to serious health concerns such as pancreatitis, bowel obstruction and a possible risk of kidney issues. While these side effects are rare, they have been enough to prompt warnings and ongoing investigations by health organisations.

One area that has not received as much attention, but is just as important, is their potential impact on gut health. If you have IBS or a sensitive gut, or you are thinking about using one of these medications to support weight loss, here is what you need to know.

How Ozempic and GLP-1 Weight Loss Drugs Work

Ozempic and Wegovy both contain semaglutide, a GLP-1 receptor agonist. Mounjaro (tirzepatide) is a dual agonist, targeting both GLP-1 and GIP receptors. These drugs, also known as GLP-1 agonists, mimic hormones your body naturally produces after eating to slow digestion, regulate blood sugar and reduce appetite.

Because they slow gastric emptying, they can make you feel full for longer. This is a big part of how they help people lose weight, but the same mechanism can lead to some gut-related side effects.

Gut-Related Side Effects: What to Watch Out For

Some of the most common side effects people report when using GLP-1 or dual agonist medications like Ozempic, Wegovy, or Mounjaro include:

Nausea
Constipation
Diarrhoea
Bloating
Stomach pain or discomfort

These symptoms occur because digestion slows significantly. Food sits in the stomach longer, which can trigger bloating or discomfort, especially in people who already deal with gut issues like IBS.

Food sits in the stomach longer, which can trigger bloating or discomfort...

There are also questions around whether these drugs could affect the gut microbiome. While there isn’t enough long-term data yet, any change in digestion could potentially alter microbial balance over time.

Gallstones and Sudden Weight Loss

One overlooked side effect of rapid weight loss is an increased risk of gallstones. This applies to Ozempic, Wegovy, and Mounjaro alike. When the body loses fat quickly, the liver secretes extra cholesterol into bile, which can form stones. This is especially important for people with IBS, as bile acid sensitivity is already a factor for many. Gallstones can lead to severe pain and even gallbladder surgery in some cases.

When the body loses fat quickly, the liver secretes extra cholesterol into bile, which can form stones.

Muscle Loss vs Fat Loss: The Hidden Risk

While these medications are effective at reducing overall weight, not all of that weight is fat. People using GLP-1 and dual agonist drugs often lose lean muscle as well. This matters because muscle helps maintain metabolic rate. When you stop taking the medication, weight regain tends to happen faster than muscle rebuild.

Some clinicians and the media have also pointed to a phenomenon dubbed “Ozempic face", a gaunt, prematurely aged look linked to rapid fat and muscle loss in the face. Celebrities such as Scott Disick and Sharon Osbourne have been highlighted in the media as examples.

So although the number on the scales may go down, the body composition changes might not be ideal.

To protect your muscle mass, it’s essential to:

Eat adequate protein (aim for a minimum of 1.2g per kg bodyweight)
Strength train 2-3x per week

Without this, you risk ending up with a slower metabolism, more fat regain and less strength.

Protecting Your Gut and Muscles on GLP-1 Agonists

If you’re considering one of these medications, or already using them, here’s how to support your gut and preserve muscle:

Prioritise whole foods and avoid ultra-processed meals that can worsen bloating
Include fermented foods like kefir, sauerkraut, or yoghurt to help gut bacteria
Get 25–30g of fibre daily from varied sources
Walk daily to support digestion
Use natural laxatives like magnesium citrate if constipation becomes an issue
Strength train regularly and make protein a non-negotiable

These habits will help balance your digestive system and reduce the side effects many people experience.

Safety of Weight Loss Drugs for Long-Term Gut Health?

There’s still a lot we don’t know. While these drugs are safe for most people short-term, long-term gut health data is limited. For those with existing gut conditions like IBS, IBD, or sensitive digestion, the slowed motility and changes to the gut microbiome could worsen symptoms.

It’s also worth noting that these drugs were primarily developed for people with type 2 diabetes or obesity. Ongoing use for cosmetic weight loss remains a controversial topic.

For those with existing gut conditions like IBS, IBD, or sensitive digestion, the slowed motility and changes to the gut microbiome could worsen symptoms.

Final Thoughts

Ozempic, Wegovy and Mounjaro can be helpful tools, especially for those with type 2 diabetes or higher weight-related health risks. But they’re not a shortcut. If you’re going to use them, be intentional about protecting your gut and your muscle mass.

Supporting digestion, keeping an eye on symptoms, and maintaining a good diet and exercise routine will go a long way in preventing unpleasant side effects and long-term issues.

Want Support While Using Weight Loss Medications?

If you’re thinking about taking a weight loss medication like Ozempic, Wegovy or Mounjaro, or you’re already on one, it’s important to protect your gut and muscle health along the way. These drugs can be powerful tools, but they also come with side effects that are easier to manage with the right nutrition and lifestyle. If you’re experiencing gut symptoms, constipation or other side effects, I can help you create a tailored plan.

I work 1:1 with clients to create personalised nutrition plans that prioritise gut health, help preserve muscle and support sustainable weight loss. You can book a free consultation here.

Book a FREE 30-Minute Consultation Get personalised support from a Registered Nutritional Therapist if you’re using Ozempic, Wegovy or Mounjaro. I’ll help you manage side effects, support digestion, balance blood sugar and protect muscle health, with a plan tailored to your body and your goals.