Wegovy Diarrhoea After 6 Months: Why It Can Persist and What to Do

Why is diarrhoea still happening six months in, not just at the start?

Most GLP-1 side-effect guides focus on the first few weeks, so it's natural to feel confused if loose stools appear or persist well past that point. The core reason is pharmacological: semaglutide slows gastric emptying and alters how bile acids move through the gut. For many people this leads to an early wave of nausea and diarrhoea that settles as the body adjusts. For others, especially those who have recently moved to a higher dose, the gut essentially repeats its adjustment process from scratch.

At the six-month mark, many patients are at or approaching the 1.7mg or 2.4mg maintenance dose (and potentially the newer 7.2mg option, if that applies to their prescription). Each step up carries a renewed window of GI sensitivity. It is also possible that dietary habits have shifted (eating larger portions as appetite briefly recovers, or eating faster) which the slowed gut then struggles to handle. Our general Wegovy side effects guide covers the full picture across the titration journey, which is useful context alongside the information here.

Late-onset diarrhoea, meaning a fresh episode that begins after months of stability, is worth treating as its own signal. Bile acid malabsorption has been identified as a mechanism in some patients on GLP-1 medicines, the gut's handling of dietary fat changes, and unabsorbed bile acids can trigger loose, often fatty stools. If you are specifically trying to understand what causes diarrhoea after taking Wegovy, including the timing and mechanisms involved, that dedicated guide goes into more detail than we can cover here. This is not a reason to panic, but it is a reason to log what you're eating and when symptoms occur, and to bring that pattern to your prescriber.

What does 'when to get medical help' actually mean for this symptom?

Diarrhoea that is mild and linked to a recent dose change, or to a specific meal, usually resolves without intervention. The situation that warrants same-day or urgent help is different in character.

Seek medical attention promptly if: diarrhoea is severe enough that you cannot stay hydrated; if you notice signs of dehydration (feeling faint when you stand, a dry mouth that won't clear, significantly reduced urine); if stools contain blood or are black and tarry; or if the diarrhoea is accompanied by a fever. These are not expected features of semaglutide's GI profile and need a clinician to rule out an unrelated cause.

The symptom that requires emergency assessment is severe, persistent abdominal pain radiating to the back, with or without vomiting. In January 2026, the MHRA issued a formal Drug Safety Update reinforcing that acute pancreatitis is a known, infrequent but serious risk with GLP-1 medicines; that specific pain pattern is not ordinary diarrhoea and needs emergency evaluation. Call 999 or go to A&E if it fits that description.

For symptoms that are troublesome but not urgent, your prescriber is the right first step. Notes on timing, frequency and what seems to trigger episodes will make that conversation much more useful. You can also explore the link between Wegovy and diarrhoea after eating specifically, which often has its own pattern and practical fixes.

Does persistent diarrhoea mean Wegovy should be stopped or the dose reduced?

Not automatically, and that call belongs to your prescriber. Some patients do better temporarily pausing a dose increase and staying at the previous level for longer; others find that symptoms resolve once they adjust their meal composition. Eating smaller portions, reducing very high-fat foods, staying well hydrated and giving the gut time are often the first practical steps.

Stopping treatment entirely is rarely the right answer for a symptom that is manageable, because the clinical benefits of continued treatment are meaningful. The STEP 1 trial, published in the New England Journal of Medicine, showed an average weight reduction of around 15% over 68 weeks at the 2.4mg dose, a result that has clinical relevance beyond just the number. Interrupting treatment, then restarting it after a break, often resets the GI adjustment process, which can temporarily make things worse rather than better.

What your prescriber needs to know is: how frequent is this, how severe, how long does each episode last, and what, if anything, appears to trigger it. That pattern helps distinguish between a dose-adjustment effect that will settle and something that needs investigation. A broader look at how Wegovy's side effects change after six months can also help you put the diarrhoea in context alongside other symptoms you may be experiencing.

How does ongoing clinical oversight help manage this?

Wegovy is a prescription-only medicine precisely because the decisions around dose, timing and managing side effects are clinical ones. An online pharmacy that does not re-review your case before each repeat order is not doing its job, and a side effect that has been present for weeks deserves to be on a prescriber's radar, not managed in isolation.

At nume, every repeat order is reviewed by a GPhC-registered prescriber before it is dispensed. Our aftercare team is available seven days a week, so if diarrhoea is disrupting your life mid-cycle you don't have to wait until your next order to raise it. If you're considering starting treatment and want to understand how side effects are monitored from the outset, our free consultation is the place to have that conversation openly. There's more general context about the treatment itself on the Wegovy overview page if you want to read wider before you do.

Side effects are part of the clinical picture, not a separate concern. That's what a prescriber-led review at every stage is for.