The most common side effects of Wegovy (semaglutide 2.4 mg) are nausea, diarrhoea, vomiting and constipation. Singapore's registered product information reports nausea in 43.9% of adults on semaglutide against 16.1% on placebo over 68 weeks (HSA insert). Most nausea, diarrhoea and vomiting were mild to moderate and short-lived, a median of 8 days for nausea, while constipation lasted longer, a median of 47 days. At GetLean, daily WhatsApp coaching means anything clinical can reach Dr Quek early.

Availability in Singapore. This medicine is registered with Singapore's Health Sciences Authority, and its registered indication includes weight management. Which medicine suits a particular person, if any does, is decided by the doctor who assesses them.

What are the most common side effects of Wegovy?

The most common side effects of Wegovy are digestive: in the US label's pooled weight-loss trials, nausea, diarrhoea, vomiting, constipation and stomach pain each affected between 20% and 44% of adults on semaglutide 2.4 mg, against 6% to 16% on placebo. The trials treated 2,116 adults for up to 68 weeks, 14% of them Asian, and 73% reported a digestive side effect of some kind, against 47% on placebo (US label).

The share of adults reporting each reaction in the US label's pooled weight-loss trials, semaglutide 2.4 mg against placebo.

Reported by adults in the trials Placebo Semaglutide 2.4 mg
Nausea 16% 44%
Diarrhoea 16% 30%
Vomiting 6% 24%
Constipation 11% 24%
Stomach pain 10% 20%
Headache 10% 14%
Tiredness 5% 11%
Indigestion 3% 9%
Dizziness 4% 8%
Bloating 5% 7%
Burping under 1% 7%
Low blood sugar (type 2 diabetes only) 2% 6%
Wind 4% 6%
Stomach upset (gastroenteritis) 4% 6%
Reflux 3% 5%
Stomach lining inflammation (gastritis) 1% 4%
Viral stomach upset 3% 4%
Hair loss 1% 3%
Altered skin sensation 1% 2%

Singapore's insert sorts the same reactions by how often they occur. It classes headache, vomiting, diarrhoea, constipation, nausea, stomach pain and tiredness as very common, at least 1 in 10 people, and mainly seen while the dose was being stepped up; bloating, burping, wind, gallstones and hair loss as common; and acute pancreatitis as uncommon, between 1 in 1,000 and 1 in 100 (HSA insert).

Injection-site reactions, such as itching, redness or irritation where the needle went in, were reported by 1.4% of adults on semaglutide 2.4 mg against 1% on placebo (US label).

What is the biggest side effect of Wegovy?

The biggest side effect of Wegovy, and of semaglutide 2.4 mg, is nausea: it is the most common one, affecting 44% of adults in the US label's trials against 16% on placebo (US label), and 43.9% against 16.1% in Singapore's insert (HSA insert). Biggest here means most common; the serious side effects are rarer, and they are set out below. Nausea was also the side effect that most often made people stop: 1.8% of adults stopped treatment because of it, against 0.2% on placebo (US label).

How long do Wegovy side effects last?

Most of Wegovy's digestive side effects last days, not months: in Singapore's insert, nausea lasted a median of 8 days, vomiting 2 days and diarrhoea 3 days, while constipation lasted longer, a median of 47 days (HSA insert). They cluster at the start: the US label says these reactions were most frequently reported during dosage escalation (US label), and in STEP 1, the main weight-loss trial, nausea and diarrhoea were typically transient and mild to moderate and subsided with time (Wilding 2021).

Singapore's product information steps the dose up over 16 weeks, from 0.25 mg to the 2.4 mg maintenance dose, to reduce the likelihood of stomach symptoms. It also tells the prescriber that with significant stomach symptoms the next step can be delayed, or the dose lowered to the previous one, until they improve (NDF). That is the prescribing doctor's decision, not one to make on your own.

For a minority, side effects do not settle: 4.3% of adults stopped treatment permanently because of a digestive side effect, against 0.7% on placebo (US label).

Why is my belly bigger on Wegovy?

A bigger or bloated belly on Wegovy can come from its digestive side effects: bloating was reported by 7% of adults on semaglutide 2.4 mg against 5% on placebo, burping by 7% against under 1%, wind by 6% against 4% and constipation by 24% against 11% (US label). Singapore's insert lists bloating, burping and wind as common (HSA insert).

Neither label describes a growing belly as a side effect: a full-text search of Singapore's insert and the US label finds "belly" only in the injection instructions. Severe or worsening swelling with pain or vomiting is a reason to call a doctor. Severe digestive reactions affected 4.1% of adults on semaglutide 2.4 mg against 0.9% on placebo (US label), and blockage of the bowel and severe constipation have been reported since approval (US label). Constipation and reflux on GLP-1 covers the bowel side of it.

What are the serious side effects of Wegovy?

The serious side effects of Wegovy are uncommon to rare: acute pancreatitis, gallbladder disease, kidney injury from dehydration, severe digestive reactions, serious allergic reactions and, very rarely, a sudden loss of vision called NAION. Singapore's insert gives these figures and wording (HSA insert), with the US label's where the insert gives none (US label):

  • Acute pancreatitis: confirmed in 0.2% of adults on semaglutide and under 0.1% on placebo. The US label adds that fatal and non-fatal cases have been observed in people treated with GLP-1 medicines, semaglutide included.
  • Gallbladder disease: gallstones in 1.6% and gallbladder inflammation in 0.6%, against 1.1% and 0.3% on placebo.
  • Kidney problems after dehydration: Singapore's insert says nausea, vomiting and diarrhoea can cause dehydration, which in rare cases leads to a deterioration of kidney function. The US label reports acute kidney injury at 0.4 cases per 100 patient-years against 0.2 on placebo, and reports since approval of cases needing dialysis.
  • Serious allergic reactions: anaphylaxis and swelling of the face and throat (angioedema) are listed as rare.
  • Sudden vision loss (NAION): listed as very rare. Studies in adults with type 2 diabetes suggest about one additional case per 10,000 person-years of treatment, and the insert says a sudden loss of vision should lead to an eye examination.
  • Low blood sugar with type 2 diabetes: 6.2% against 2.5% on placebo in STEP 2, the trial in adults with type 2 diabetes, and the risk is higher alongside a sulfonylurea or insulin.
  • Low blood pressure and fainting: low blood pressure in 1.3% against 0.4%, and fainting in 0.8% against 0.2% (US label).
  • Heart rate: a mean rise of 3 beats per minute.

In rodents, semaglutide caused thyroid C-cell tumours. Singapore's insert considers the relevance for humans low but says it cannot be completely excluded, and lists hypersensitivity as its only contraindication (HSA insert); the US label carries a boxed warning and rules semaglutide out for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2 (US label).

Can Wegovy do permanent damage?

Wegovy's prescribing information does not describe any side effect as permanent, but it does list serious risks that need medical care. The gravest are acute pancreatitis, where the US label notes fatal and non-fatal cases with GLP-1 medicines; kidney injury after dehydration, in some cases needing dialysis (US label); gallbladder problems, some of which need surgery (US Medication Guide); and, in Singapore's insert, a very rare risk of sudden vision loss (HSA insert). The labels do not say whether any of these leaves lasting harm.

How we checked: on 25 October 2026 we searched the full text of Singapore's insert and of the US label for "permanent" and "irreversible". Every hit was about people permanently stopping treatment, not about a side effect. Severe stomach pain that will not go away, or a sudden loss of vision, needs urgent medical care rather than a wait for the next review.

Does Wegovy cause hair loss?

Wegovy can cause hair loss in a small share of people: Singapore's insert reports it in 2.5% of adults on semaglutide against 1.0% on placebo, mainly mild, with most people recovering while still on treatment, and more often in those who lost 20% of their weight or more (HSA insert). The US label reports 3.3% against 1%, in 4% of women and 0.9% of men, and links it to weight reduction (US label). Hair shedding on GLP-1 covers what it looks like and how long it lasts.

When should you call a doctor about Wegovy side effects?

Call a doctor straight away about severe stomach pain that will not go away, signs of a serious allergic reaction, a sudden loss of vision, or nausea, vomiting or diarrhoea that does not settle. The US Medication Guide singles out these (US Medication Guide):

  • Severe pain in the stomach area that will not go away, with or without nausea or vomiting, sometimes felt through to the back: the guide says to stop using the medicine and call the doctor right away, because it can be pancreatitis.
  • Pain in the upper stomach, fever, yellowing of the skin or eyes, or clay-coloured stools: possible gallbladder problems.
  • Swelling of the face, lips, tongue or throat, problems breathing or swallowing, severe rash or itching, fainting or dizziness, or a very rapid heartbeat: the guide says to stop and get medical help right away.
  • Nausea, vomiting or diarrhoea that does not go away: the fluid loss can lead to kidney problems, and the guide says it is important to drink fluids.
  • A racing or pounding heart that lasts several minutes.
  • A lump or swelling in the neck, hoarseness, trouble swallowing or shortness of breath: symptoms the guide asks people to report because of the thyroid warning.

Singapore's insert adds that a sudden loss of vision should lead to an eye examination (HSA insert). The guide also asks people to talk to their healthcare provider about any side effect that bothers them or does not go away. Any change to a prescribed dose is a decision for the prescribing doctor.

Side effects are why daily contact matters: at GetLean, daily WhatsApp coaching keeps you in touch with our care team (9am to 9pm every day, Singapore time), so anything clinical can reach Dr Quek early, not weeks later. Outside those hours an urgent symptom does not wait for a reply: go to an emergency department, or call 995 if it is an emergency.

What foods should you avoid on Wegovy?

The labels name no foods to avoid on Wegovy: Singapore's product information says it is taken once weekly at any time of the day, with or without meals (NDF), and the US labels list no food or drink to avoid (US labels). They carry no alcohol-specific warning either (US labels), which is not the same as saying alcohol is safe. What the labels do say to avoid:

  • Other GLP-1 medicines: the US Medication Guide says semaglutide should not be used with other semaglutide-containing products or other GLP-1 receptor agonist medicines (US Medication Guide).
  • Dehydration: drink fluids, the guide says, and Singapore's insert advises precautions to avoid fluid loss (HSA insert).
  • Pregnancy: Singapore's insert says to stop semaglutide at least 2 months before a planned pregnancy (HSA insert).
  • Surgery and sedation: tell every doctor before a planned operation or procedure under anaesthesia or deep sedation (US Medication Guide).

Managing nausea on GLP-1 goes through the usual food lists against the label, and alcohol on GLP-1 covers drinking.

What does GetLean do about side effects on Wegovy?

At GetLean, anything clinical you raise on daily WhatsApp coaching goes to Dr Quek, and he reviews how it is going every month, with dose changes made at that check-in, towards the lowest effective dose. Wegovy at GetLean is from S$488 a month (S$788 depending on dose, S$1,088 at the max dose), all-in: Dr Quek's video consultations and reviews, the medication delivered to you, and daily WhatsApp coaching. Wegovy in Singapore has the price for each dose.

The first step is a 30-minute video consultation with Dr Quek for S$20, refunded in full if he decides medication is not right for you, and a consultation does not guarantee a prescription. Mounjaro side effects has the equivalent figures for tirzepatide, and GLP-1 side effects sorts the class by how serious each effect is.

Book your consult with Dr Quek.

Common questions

What are the side effects of Wegovy?

The most common side effects of Wegovy (semaglutide 2.4 mg) are nausea, diarrhoea, vomiting and constipation. In the US label's weight-loss trials, nausea, diarrhoea, vomiting, constipation and stomach pain each affected between 20% and 44% of adults on semaglutide 2.4 mg, against 6% to 16% on placebo (US label), and Singapore's insert reports nausea in 43.9% against 16.1% (HSA insert).

What is the biggest side effect of Wegovy?

The biggest side effect of Wegovy, and of semaglutide 2.4 mg, is nausea: it is the most common one, affecting 44% of adults in the US label's trials against 16% on placebo (US label), and 43.9% against 16.1% in Singapore's insert (HSA insert). Biggest here means most common; the serious side effects are rarer.

How long do Wegovy side effects last?

Most of Wegovy's digestive side effects last days, not months: in Singapore's insert, nausea lasted a median of 8 days, vomiting 2 days and diarrhoea 3 days, while constipation lasted longer, a median of 47 days (HSA insert). The US label says these reactions were most frequently reported during dosage escalation (US label).

What if Wegovy side effects start and my next appointment is months away?

Talk to the prescribing doctor about any side effect that bothers you or does not go away, as the US Medication Guide asks, without waiting for the next scheduled appointment, and do not change the dose yourself (US Medication Guide). Severe stomach pain that will not go away, or signs of a serious allergic reaction, need help right away. At GetLean, daily WhatsApp coaching keeps you in touch with the care team (9am to 9pm every day, Singapore time), so anything clinical can reach Dr Quek early, and Dr Quek decides any dose change. Outside those hours an urgent symptom does not wait for a reply: go to an emergency department, or call 995 if it is an emergency.

Why is my belly bigger on Wegovy?

A bigger or bloated belly on Wegovy can come from its digestive side effects: bloating was reported by 7% of adults on semaglutide 2.4 mg against 5% on placebo, burping by 7% against under 1%, wind by 6% against 4% and constipation by 24% against 11% (US label). Neither label describes a growing belly as a side effect, and severe or worsening swelling with pain or vomiting is a reason to call a doctor.

Can Wegovy do permanent damage?

Wegovy's prescribing information does not describe any side effect as permanent, but it does list serious risks that need medical care: acute pancreatitis, gallbladder disease, kidney injury after dehydration and severe digestive reactions, and Singapore's insert adds a very rare risk of sudden vision loss (NAION) (US label; HSA insert). The labels do not say whether any of these leaves lasting harm.

Does Wegovy cause hair loss?

Wegovy can cause hair loss in a small share of people: Singapore's insert reports it in 2.5% of adults on semaglutide against 1.0% on placebo, mainly mild, with most people recovering while still on treatment, and more often in those who lost 20% of their weight or more (HSA insert).

What foods should you avoid on Wegovy?

The labels name no foods to avoid on Wegovy: Singapore's product information says it is taken once weekly at any time of the day, with or without meals (NDF), and the US labels list no food or drink to avoid (US labels). What they do say is to drink fluids to reduce the chance of dehydration.