Ozempic constipation and bloating. How to ease GLP-1 gut side effects

About 1 in 4 people on a weight loss dose of semaglutide get constipated. That is the drug sold as Ozempic and Wegovy. In the big trials, constipation affected 24% of people on the medicine, compared with 11% on a dummy injection.

If you are dealing with Ozempic constipation, bloating or burping, you are not alone and you are not doing anything wrong. These medicines work in your gut, so your gut feels it first. The good news is that most of these side effects are mild, and food and daily habits can ease a lot of them.

In my clinic I always ask clients about their sleep, their gut and their poop. On GLP-1 medicines, that last question matters more than ever. Here is what the research shows and the gentle steps I suggest.

One rule before we start. Never change, skip or stop your medicine dose on your own. Every tip here works alongside your doctor’s plan, not instead of it.

Why do GLP-1 medicines cause constipation and bloating?

GLP-1 medicines copy a hormone your own gut already makes. GLP-1 is released by cells in your intestine after you eat. It tells your brain you are full and slows the movement of food through your gut.

The medicines semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) act on this same system, but much more strongly and for much longer. A slower gut means less hunger. It can also mean slower, harder stools, trapped gas and that heavy, full feeling.

There is a second, quieter reason. A Spanish expert consensus points out that many people drink less water on these medicines because they feel so full. Less food, less fibre and less fluid together are a classic recipe for constipation.

A myth worth correcting

Many people believe these medicines simply freeze the stomach. The picture is more mixed. In a 2021 trial of 72 adults, semaglutide cut the amount people ate at a buffet lunch by 35%. Yet after 20 weeks, the researchers found no clear sign of slower stomach emptying, measured with an indirect test.

So a lot of the effect seems to come from appetite and brain signals, not only from a slow stomach. That said, a 2026 review of case reports found that a small number of people do develop serious stomach slowing called gastroparesis. It often appeared after a fast dose increase, and it settled when the medicine was stopped under medical care.

How common is Ozempic constipation?

Constipation is one of the 4 most common gut side effects. A pooled analysis of the STEP 1 to 3 trials included 2,117 people on semaglutide 2.4 mg and 1,262 on a dummy injection. Here is what they reported over 68 weeks.

• Nausea in 43.9% on semaglutide, versus 16.1% on the dummy injection
• Diarrhoea in 29.7%, versus 15.9%
• Vomiting in 24.5%, versus 6.3%
• Constipation in 24.2%, versus 11.1%

The same analysis found that 98.1% of these side effects were mild or moderate. Most came during or soon after a dose increase and then faded. Only 4.3% of people stopped the medicine because of gut symptoms.

With tirzepatide, a 2025 nutrition advisory summarised the trial data as constipation in 11% at the 15 mg dose, versus 5% on a dummy injection. In the trials of both medicines, bloating, burping and wind were less common, each affecting fewer than 1 in 10 people.

Why constipation can hang around longer

Nausea often fades within weeks. Constipation tends to last longer. The Spanish consensus reports that it lasted a median of 47 days in people with obesity on these medicines. It most often starts in the first 16 weeks, especially the first 28 days. So it is worth acting early, before it builds up.

How can I relieve constipation on Ozempic?

Start with water, movement and slow, steady fibre. These are the first steps that both the Spanish consensus and the 2025 joint nutrition advisory recommend. The advisory comes from 4 American groups, including the American Society for Nutrition and the Obesity Society.

Try this. Drink before you feel thirsty

Your thirst signal may be quieter on these medicines. Keep a bottle where you can see it and sip through the day. Plain water, herbal teas and clear soups all count.

This matters for more than your bowels. The 2025 advisory warns that dehydration from vomiting or diarrhoea can harm the kidneys. If you cannot keep fluids down, call your doctor the same day.

A mineral water rich in magnesium and sulfate may also help. In a 2026 trial, drinking 1 litre a day (about 34 fluid ounces) raised bowel movements more than a low mineral water after 2 weeks. The effect was stronger in people with worse constipation.

Try this. Add fibre slowly, and pick gentle types

The advisory suggests a gradual increase in fibre from food, such as prunes and other dried fruit. Going from very little fibre to a lot overnight usually makes bloating worse. Add one fibre food every few days.

Three foods have good trial evidence for constipation.

• Green kiwifruit. A 2021 US trial tested 79 adults with constipation for 4 weeks. Eating 2 kiwis a day, 100 g of prunes (about 3.5 ounces) or 12 g of psyllium all increased complete bowel movements. Kiwi caused the fewest side effects.
• Prunes. In a 2019 UK trial, 80 g of prunes a day (about 2.8 ounces) increased stool weight and frequency. They did cause more wind, so start with a few.
• Psyllium husk. This soluble fibre holds water and softens stools. Start with half to 1 teaspoon in a big glass of water and build up slowly.

British Dietetic Association guidelines from 2025, based on 75 trials, also back kiwifruit, prunes, rye bread, fibre supplements and high mineral water for constipation. Read more in my guide to kiwi, psyllium and what really works for constipation.

Try this. Move a little after meals

Movement helps your gut move too. The Spanish experts advise more daily movement for constipation on these medicines. A 10 minute walk after your main meal is an easy start.

Watch the protein and fat balance

Here is a tricky one. The 2025 advisory notes that foods high in protein or fat can slow the stomach further and may worsen constipation. Yet protein is also vital to protect your muscle while you lose weight.

The answer is balance, not avoidance. Spread protein across small meals and pair it with vegetables, fruit or whole grains. Keep fried and very fatty foods for small portions.

If food is not enough

The advisory mentions magnesium citrate as an option when diet changes do not work. Please ask your doctor or pharmacist first. Magnesium is not safe for everyone, especially people with kidney disease. Stool softeners and laxatives should also be chosen with your doctor.

What helps bloating and burping on GLP-1 medicines?

Eat smaller meals, slowly, and stop at the first sign of fullness. This is the core advice from the Spanish consensus, and it fits what I see when people learn to eat with their new appetite.

• Eat slowly and without screens, so you notice fullness early
• Choose smaller portions and eat more often if you need to
• Stop eating as soon as you feel full, even if food is left on the plate
• Do not lie down straight after a meal
• Avoid eating close to bedtime
• Skip straws and fizzy drinks, which add swallowed air
• Go easy on alcohol, which the advisory suggests keeping to a minimum

For nausea, the 2025 advisory suggests a small breakfast, then small meals every 3 to 4 hours with enough fluid. Ginger or peppermint tea may help too. If bloating is your main problem, my article on 12 common bloating causes covers salt, sugar alcohols and other hidden triggers.

How much protein do I need on Ozempic?

Most adults need at least 0.8 g of protein per kg of body weight each day, and more may help during weight loss. The 2025 advisory notes that targets of 1.2 to 1.6 g per kg have been proposed while losing weight. The right number for you depends on your body, so a dietitian can help.

For example, a person weighing 70 kg (about 154 lb) would need at least 56 g a day at 0.8 g per kg. At 1.2 g per kg, that becomes about 84 g a day.

When your appetite is small, every bite counts. Gentle protein foods include eggs, Greek yogurt or lactose-free yogurt, tofu, fish, chicken, lentils in small portions and milk or soy drinks. Strength training also helps protect muscle, as the advisory stresses.

Small studies are now testing easy ways to do this. A 2026 pilot study gave 20 people on Ozempic or Wegovy a plant-based shake high in protein and fibre. It raised their daily protein and fibre without worsening gut symptoms. Bloating and constipation scores were lower 2 hours after the first shake. Over the full week, the changes were not significant. This was a small, short study linked to the shake maker, so it is a promising idea, not proof.

What does your gut microbiome have to do with GLP-1?

I strongly believe gut health plays a major role in nearly every health condition, and GLP-1 is a perfect example. GLP-1 is a gut hormone. Your gut bacteria help control how much of it your own body makes.

When gut bacteria ferment fibre, they make short chain fatty acids. A 2026 review in Advances in Nutrition explains that these compounds can prompt your gut cells to release more of your own GLP-1. The same review notes that fibre can support regular bowels and a healthier gut barrier.

Another 2026 review describes a two-way link. Gut bacteria shape GLP-1 signals, and GLP-1 medicines seem to shift the mix of gut bacteria in return. Researchers think your starting microbiome may even affect how well the medicine works for you. These ideas are still early and mostly come from reviews, not large human trials.

So feeding your gut bacteria is a smart move on these medicines, and even more so if you ever stop. The reviewers call for trials that combine GLP-1 medicines with specific fibres, which do not exist yet. Until then, a wide variety of plant foods is the safest bet. My Gut Garden game makes counting your plants each week a little more fun.

Is it Ozempic or something more serious?

Most gut side effects are mild, but rare serious problems do happen. A 2023 Canadian database study in JAMA looked at GLP-1 use for weight loss. It found higher rates of pancreatitis, bowel blockage and gastroparesis than with another weight loss medicine.

The evidence is still debated. A 2026 Japanese study of 298,124 adults with type 2 diabetes found no higher risk of bowel blockage in the first year. It affected 0.14% of people starting a GLP-1 medicine and 0.17% of those starting a different diabetes medicine. A 2026 review in the Journal of Internal Medicine concluded that for bowel blockage, cause and effect remains uncertain. Gallbladder problems had the most consistent evidence of a link. Because these events are rare, the review adds, even a large rise in risk means a small change for most people.

What this means for you is simple. Common side effects are worth managing at home. Warning signs are worth a call to your doctor straight away. The box on this page lists them.

Frequently asked questions

How long does constipation from Ozempic last?

For many people it improves as the body adjusts, but it can last longer than nausea. A Spanish expert review reported a median of 47 days in people with obesity. It often starts in the first month and after dose increases. If you have not had a bowel movement in several days, or you feel bloated and in pain, call your doctor.

What foods help Ozempic constipation?

Green kiwifruit, prunes, psyllium husk and rye bread have the best evidence for constipation in general. Add them slowly and drink plenty of fluid with them. Small portions of oats, chia seeds, lentils and vegetables help too. There are no trials yet of these foods in people taking GLP-1 medicines specifically.

Why do I feel so bloated on Wegovy or Mounjaro?

These medicines slow the movement of food and gas through your gut, and many people eat and drink differently on them. Large meals, fizzy drinks, fatty foods and fast eating can all make bloating worse. Smaller meals eaten slowly usually help. If bloating is severe or comes with vomiting or belly pain, see a doctor.

Should I take a fibre supplement on GLP-1 medicines?

A gentle soluble fibre such as psyllium can help constipation if food is not enough. Start with a small dose and drink plenty of water with it, or it can make you feel more full and bloated. Check with your doctor first, especially if you have had gastroparesis or a bowel blockage.

Can I stop my medicine if the side effects are bad?

Please do not stop or change your dose without your doctor. Doctors can slow your dose increases, pause at a lower dose or treat specific symptoms. Severe or ongoing symptoms always need medical advice, not a home fix.

What I want you to remember

Constipation and bloating on GLP-1 medicines are common, usually mild and often strongest in the first weeks and after each dose increase. Drink before you feel thirsty, add fibre slowly, move after meals and eat small meals slowly.

Your gut is doing a lot of the work behind these medicines, so treat it kindly. Feed your gut bacteria with a variety of plants, protect your muscle with enough protein and keep talking to your doctor about how you feel.

Curious about your own gut habits? Take my 2 minute Gut Check quiz or read why fibre needs a slow start. You can also join the free 30-Day Calm Gut Challenge for one small habit each day.