Constant Diarrhoea on Wegovy: What to Expect and When to Get Help

Step 1: Recognise what's driving the loose stools

Semaglutide slows the rate at which food leaves the stomach and alters gut motility across the digestive tract. For some people this produces constipation; for others (particularly early in treatment) it tips the other way toward loose, frequent stools. The NHS's patient information on semaglutide lists diarrhoea among the common side effects, meaning it affects at least 1 in 10 people using the medicine.

The pattern matters. Diarrhoea that begins shortly after starting Wegovy or stepping up to a new dose, stays mild, and gradually improves over one to three weeks is consistent with the body's normal adjustment. A question our prescribers hear most weeks is whether the loose stools will ever stop, and in most cases, yes, they do, as the gut settles into the new hormonal signalling.

What's less predictable is the minority of people whose gut symptoms remain constant rather than fading. If you are several weeks into a stable dose and still experiencing frequent, watery stools every day, that warrants a conversation rather than further patience. You can read more about how diarrhoea on Wegovy typically behaves at different points in treatment on our Wegovy diarrhoea page.

Step 2: Manage day-to-day symptoms without making things worse

There are practical measures that often reduce the frequency and severity of loose stools, all consistent with NHS dietary guidance. Eating smaller, lower-fat meals reduces the gastric stimulus that can worsen gut transit. Highly processed foods, very spicy dishes, and large volumes of caffeine can all aggravate an already-sensitive gut on semaglutide; scaling these back is worth trying before assuming treatment needs to change.

Hydration is the most important immediate priority. Each episode of diarrhoea depletes fluid and electrolytes, and cumulative loss over days compounds quickly. Plain water, diluted squash, and foods with a high water content all help. Oral rehydration sachets (available over the counter at any pharmacy) are appropriate for adults experiencing frequent stools over several days.

Timing your weekly injection can also be worth adjusting with your prescriber's knowledge, some people find gut symptoms cluster around the 24–48 hours post-injection window. Spacing the injection day away from a week with heavy commitments is a small practical adjustment that can make symptoms more manageable. For a broader picture of what side effects can appear early in treatment, the Wegovy instant side effects page covers the first-dose window specifically.

Step 3: Know exactly when to stop managing and seek medical help

Watchful waiting is appropriate for mild, improving symptoms. It is not appropriate for any of the following, and you should seek same-day medical advice or go to A&E if you experience them:

Signs of dehydration: feeling very thirsty, passing dark or very little urine, dizziness when standing, confusion, or rapid heartbeat. Kidney function can be affected if dehydration is significant and prolonged, the NHS England guidance on weight-management injections specifically names dehydration from severe gastrointestinal illness as a reason to seek urgent care.

Severe or persistent stomach pain: particularly pain that is intense, constant, and radiates toward the back, with or without vomiting. This pattern can indicate acute pancreatitis, which the MHRA flagged in a Drug Safety Update for GLP-1 medicines, the symptom demands urgent assessment, not home management.

Blood in stools or black, tarry stools: always warrant urgent review, regardless of what medicine you are taking.

Constant diarrhoea with no sign of improvement after three to four weeks on a stable dose is also a reason to contact your prescriber rather than continuing to wait. Persistent symptoms may indicate that the current dose is not well tolerated, and a prescriber can consider whether a slower titration is appropriate. Our guide to severe diarrhoea on Wegovy explores the more significant end of the spectrum in detail.

Reporting your experience and getting ongoing support

Side effects from prescription medicines, including gut symptoms on Wegovy, can be reported to the MHRA through the Yellow Card scheme. You do not need to be certain a side effect was caused by the medicine, suspected reactions are exactly what the scheme is designed to capture, and reports from patients contribute directly to the safety monitoring of medicines like semaglutide.

Beyond formal reporting, ongoing clinical support is the practical safeguard. At nume, a prescriber is involved at every repeat, not just at the start. If diarrhoea on Wegovy is affecting your quality of life or making you consider stopping treatment, that is a clinical conversation worth having rather than a decision to make alone. Our full Wegovy side effects page covers the complete profile, and if burping is accompanying the gut symptoms, the Wegovy constant burping page addresses that separately. For a broader overview of semaglutide, the Wegovy treatment page is a good starting point.

If you have questions about whether Wegovy is still appropriate given how your body is responding, speaking to our prescribers is the right next step. Side effect management is part of the clinical picture, not an afterthought.