Most writing about weight-loss medicines focuses on who they can help. This article does the opposite job, and it matters just as much: setting out clearly who should not take the Wegovy pill, who needs extra caution, and why those lines exist. If you recognise yourself below, that is not a door closing on your weight-management goals; it is the reason assessments exist, and there are usually alternatives to discuss.
Clear exclusions
Pregnancy heads the list. Semaglutide should not be used during pregnancy, while trying to conceive, or while breastfeeding, and it should be stopped in advance of a planned pregnancy. This is not bureaucratic caution: animal studies raised concerns about fetal development, weight loss itself is not advised in pregnancy, and human safety data does not exist and never ethically will. Because weight loss can also restore fertility in people who had stopped ovulating regularly, reliable contraception during treatment is part of the same picture, which we cover in a dedicated article on Wegovy and contraception.
A known allergy to semaglutide or any ingredient in the tablet is an absolute exclusion, as with any medicine. And people under 18 are outside the licence for the oral weight-management product; weight management in adolescents is a specialist area with its own pathways.
Histories that need specialist judgement
Several medical histories sit in the judgement zone rather than the exclusion zone, and the judgement belongs to a prescriber who can see your records. A previous episode of pancreatitis is the most important: GLP-1 medicines carry an uncommon risk of pancreatic inflammation, and a prior history changes that calculation. Active gallbladder disease matters because rapid weight loss by any method increases gallstone risk. A personal or family history of medullary thyroid cancer or the rare syndrome MEN2 is treated as a contraindication in some countries based on animal findings. Severe gut disorders, including gastroparesis and significant inflammatory bowel disease, sit poorly with a medicine whose core action is slowing the stomach. Diabetic retinopathy needs eye monitoring if blood sugar falls quickly. And significant kidney or liver impairment calls for care, mainly because dehydration from digestive side effects hits harder.
Eligibility works both ways: not underweight, not cosmetic
The exclusion people least expect is being too light. The Wegovy pill is licensed for adults living with obesity, or overweight with at least one weight-related health condition, judged on body mass index and clinical context. Someone already at a healthy weight who wants to be slimmer for an event or a photograph is outside the licence, and a legitimate provider will decline, because the risk-benefit calculation that justifies the medicine simply does not exist at a healthy weight. The same applies to a history of eating disorders: restrictive appetite suppression can be actively harmful there, and honest screening at assessment protects people at exactly the moment they may not protect themselves.
Medicines that need thought alongside
Interactions with the Wegovy pill come in two kinds. The pharmacological kind centres on diabetes medicines: insulin and sulfonylureas combined with semaglutide can push blood sugar too low, so doses may need adjusting and monitoring stepping up. The practical kind comes from the tablet's empty-stomach rules, which complicate the timing of other morning medicines, particularly anything with its own strict window such as levothyroxine for the thyroid. Slowed stomach emptying can also alter how some medicines are absorbed. None of these usually blocks treatment, but each needs a pharmacist or prescriber to sequence things deliberately. Bring a complete medicines list, including supplements, to your assessment.
If you are ruled out, what then?
An exclusion from one medicine is not an exclusion from help. Depending on the reason, alternatives may include a different medicine in or beyond the GLP-1 class, the weekly injection rather than the daily tablet where the issue is practical, structured dietetic and activity support, treatment of an underlying condition that is driving weight, or, for some people, referral towards specialist weight-management services. The route to any of these is the same conversation that would have prescribed the pill: a clinical assessment that looks at your whole picture. If you suspect something in your history rules you out, say so up front rather than omitting it; the fastest way to the right treatment is an assessment working with complete information. Our complete guide to the Wegovy pill covers what treatment involves for those who are eligible.
Situations that pause treatment rather than prevent it
A final category is worth separating: circumstances that suspend the medicine temporarily in people who are otherwise suitable. Planned surgery is the clearest example, because semaglutide's slowed stomach emptying matters for fasting and anaesthesia; surgical and anaesthetic teams increasingly ask about GLP-1 medicines specifically, and may advise pausing in advance, so tell them you take it without being asked. Significant acute illness with vomiting or diarrhoea is another, since continuing a medicine that suppresses intake during dehydration helps nothing; prescribers often advise a short pause until you can eat and drink normally. And a decision to try for pregnancy converts a suitable patient into an unsuitable one on a planned timetable, with the medicine stopped in advance. In each case the theme is the same: these are managed interruptions agreed with your clinical team, not verdicts, and treatment commonly resumes when the circumstance passes. The habit that makes them all go smoothly is simply keeping your clinical team informed of what is happening in your life, since almost every pause is easier to plan a week ahead than to improvise on the day.
