Wegovy (semaglutide) is not suitable for everyone. Some people should not use it at all (contraindications), and others can only use it with extra caution and close monitoring. This page helps you self‑screen, understand common red flags, and know when you should pause and seek medical advice.

For the full product overview, see: Wegovy (semaglutide) weight loss injection. If you’re still at the “what is it?” stage, read What is Wegovy?.

Table of Contents

Quick safety rule (read this first)

If you have severe abdominal pain, repeated vomiting with dehydration, fainting, or any symptoms that feel sudden and severe, seek urgent medical care. Do not take another dose until you have been medically assessed.

Who should not use Wegovy (contraindications)

Contraindications are situations where Wegovy should not be used. Your prescriber will confirm these, but the most important ones to know are:

1) Allergy to semaglutide or ingredients

Do not use Wegovy if you have had an allergic reaction to semaglutide or any ingredient in the injection.

2) Pregnancy and trying to conceive

Wegovy is not recommended in pregnancy. If you become pregnant while using Wegovy, you should contact your prescriber for advice. If you are planning pregnancy, discuss timing and stopping plans with a clinician before starting.

3) Breastfeeding

Wegovy is generally not recommended while breastfeeding. Speak to a clinician about safer alternatives during this period.

High‑risk situations (use only with clinician-led caution)

Some situations are not always absolute “no” rules, but they require careful review, risk–benefit discussion, and monitoring.

Personal or family history of certain thyroid cancers

GLP‑1 medicines carry warnings relating to certain thyroid tumours in animal studies. If you have a personal or family history of medullary thyroid carcinoma or you have MEN2 (multiple endocrine neoplasia type 2), you must tell your prescriber. A clinician will decide whether Wegovy is appropriate.

History of pancreatitis or severe abdominal pain episodes

If you have had pancreatitis before, or you develop severe abdominal pain while on Wegovy, you need urgent medical review. Persistent severe abdominal pain can be a red flag.

Gallbladder problems (gallstones / cholecystitis risk)

Rapid weight loss itself can increase gallstone risk. Some people using GLP‑1 medicines can also experience gallbladder problems. If you get upper abdominal pain, fever, or persistent nausea, seek assessment.

Severe gastrointestinal disease or poor tolerability

If you have severe digestive conditions or you cannot keep fluids down due to vomiting, Wegovy may not be safe to continue without clinician review. Dose escalation may need adjustment or an alternative approach may be safer.

Diabetes medicines: hypoglycaemia risk with certain combinations

Wegovy can increase the risk of low blood sugar (hypoglycaemia) when used with some diabetes medicines (for example, insulin or sulfonylureas). If you use diabetes medication, your prescriber may need to adjust doses and monitoring.

Kidney problems (risk during dehydration)

Severe vomiting or diarrhoea can cause dehydration, which can worsen kidney function. If you have kidney disease, or you become dehydrated on Wegovy, you need medical advice promptly.

When you should stop and seek urgent advice

Stop and seek medical advice urgently if you have:

Severe, persistent abdominal pain (especially if it radiates to the back).
Repeated vomiting and you cannot keep fluids down.
Signs of dehydration (dizziness, fainting, very dark urine).
Symptoms of a serious allergic reaction (swelling, breathing difficulty).

Before you start: ‘tell your prescriber’ checklist

Tell your prescriber if you have or use:

Any history of pancreatitis or gallbladder disease.
Thyroid cancer history (personal/family) or MEN2.
Diabetes medicines (insulin or sulfonylureas especially).
Kidney disease or recurrent dehydration episodes.
Any planned pregnancy or breastfeeding.

How to access Wegovy safely (UK)

Because Wegovy is prescription-only, safe access includes eligibility checks and a medical review. Your pathway might be NHS specialist services or a regulated private clinic.

NHS pathway overview: Can you get Wegovy on the NHS?. Private pathway overview: How to get a Wegovy prescription online (UK).

FAQs

Can I use Wegovy if I’m pregnant?

No Wegovy is not recommended in pregnancy. Contact your prescriber if you become pregnant while using it.

Is Wegovy safe if I have diabetes?

It depends on your medicines and risk profile. Hypoglycaemia risk can be higher with insulin or sulfonylureas, so clinician review is essential.

What symptoms mean I should stop and seek help?

Severe abdominal pain, persistent vomiting with dehydration, fainting, or symptoms of a serious allergic reaction need urgent assessment.