GLP-1 Medication Side Effects: How to Feel Better on Mounjaro & Wegovy

GLP-1 medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are becoming increasingly prevalent tools in weight management in the UK. It’s worth understanding the potential side effects that can come with them (especially digestive) before starting to use them. As a Registered Nutritionist I support clients across the UK in managing symptoms and eating well while using GLP-1s (My GLP-1 Nutrition support).

In this blog I’ve pulled together a basic guide to explain the “why” behind common side effects and some tips on how to manage and reduce these.

Image: Alena Bogatyrenko

Why GLP-1 Medications Cause Side Effects

GLP-1 medications change how your gut and brain communicate. They:

• slow digestion

• reduce appetite

• alter gastric emptying- how quickly your stomach processes food.

• influence gut motility- the speed that food moves through your digestive system

• change hunger and satiety signalling-how the body tells you when you’re hungry or full.

These actions help support weight loss, but they also explain why symptoms such as nausea, constipation or feeling full quickly are so common.

The Most Common GLP-1 Side Effects and What Helps?

1. Nausea

This is the most frequently reported GLP-1 side effect, especially when someone increases their medication dosage.

If this effects you, try:

• small, frequent meals vs the traditional 3 main meals a day

• plain, dry foods (e.g., crackers, toast)

• ginger tea or peppermint

• avoiding high-fat meals

• eating slowly

Nausea can often improve as your body adapts.

image: Kanchanachitkhamma

2. Constipation & Sluggish Digestion

GLP-1s slow the movement of the gut i.e. speed of digestion, which can lead to constipation, which is important to support.

Nutrition strategies that help:

• soluble fibre from oats, chia, cooked vegetables

• increasing fluids

• warm drinks in the morning

• movement and walking

• avoiding adding too much fibre too quickly (to avoid bloating too)

  See here for more tips on supporting gut health.

3. Feeling Full Quickly / Low Appetite

It can become harder to meet your nutrient and protein needs, so try:

• prioritising nutrient-dense foods-i.e. more processed foods can leave you feeling full, but under-nourished

• eating protein-rich foods in small portions (eggs, yoghurt, tofu, fish)

• smoothies and soups (e.g. also an opportunity to add extra protein)

• eating every 2–3 hours

Quality over quantity is a good principle to follow.

4. Bloating or reflux

This can happen when the stomach empties more slowly.

Helpful strategies include:

• smaller meals

• reducing very rich or spicy foods

• staying upright after eating i.e. avoid the post-dinner sofa slouch!

• limiting fizzy drinks

I've offered more general tips on how and what to eat with GLP-1 medications on a previous blog here.

Important to note: Most people experience mild and temporary side effects, but if anything feels severe, prolonged or simply “not right,” (e.g. intense stomach pain, repeated vomiting, or signs of dehydration) be sure to seek advice from your GP or prescribing team.

How Nutrition Support Can Make a Difference

There's often not a lot of nutritional guidance for those taking GLP-1s unless through the NHS. Working with a Nutritionist can be invaluable to:

• reduce uncomfortable symptoms

• understand how your body responds to GLP-1 medication

• adjust your eating pattern as medication doses increase

• support digestion and gut health

• feel confident about what and how much to eat

With the right support, side effects can become manageable, your overall wellbeing improves and weight loss results are also more sustainable. For more tips on sustainable weight loss see here.

When to Seek Personalised Support

You might benefit from tailored support if you are:

• experiencing persistent nausea, constipation or reflux

• struggling to eat enough protein

• unsure what to eat with a reduced appetite

• preparing for a dose increase

• wanting more structure and confidence with food choices

Personalised support can make the process feel smoother, easier and more sustainable.

Next Steps

If you're using Mounjaro, Wegovy or another GLP-1 medication and want expert nutrition support, you can book a complimentary call to learn more about how I can help.

Book a free 20 minute call here to discuss your symptoms.

About Amanda

Amanda is a London Nutritionist who supports clients online and in person with GLP-1 Nutrition Support and offers specific programmes: Optimising Health, Gut Health, Women's Health and Menopause. She also has a passion for all things Health and Corporate Wellbeing. Read more about Amanda here.

References:

1. Wilding, JPH. Batterham, RL. Davies, M. (2022), STEP 1 Study Group. Weight regain and Cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension, Diabetes Obes Metab, Aug; 24 (8): 1553-1564.