Ozempic Side Effects

Most common side effects

The side effects that occur most often with Ozempic are gastrointestinal symptoms: nausea (up to 20 percent of users), diarrhoea (up to 12 percent), constipation (up to 7 percent), abdominal pain and vomiting. These arise because semaglutide slows gastric emptying and acts on gut nerves.

In addition, people often report headache, fatigue, dizziness and reduced appetite (which is in part the intended effect). In patients with type 2 diabetes, hypoglycaemia also occurs, especially in combination with sulfonylureas or insulin.

Less common but well known: reflux or heartburn, belching, reduced sense of taste, hair loss (usually mild and transient), injection-site reactions (redness, itching, small bumps).

How long do side effects last?

For the majority of users, side effects are worst in the first 2 weeks after a dose increase. After that the body adjusts to the new dose and symptoms usually disappear completely within 4 weeks or become very mild.

In around 5 to 10 percent of people, digestive symptoms persist for longer. In that case the patient often stays on a lower dose for a longer period or is switched to a different medicine.

Rare but serious risks

Pancreatitis (inflammation of the pancreas) occurs in fewer than 0.5 percent of users. Symptoms are severe, persistent abdominal pain radiating to the back, often with nausea. This is a reason to stop immediately and go to the emergency department.

Gallstones and gallbladder inflammation occur somewhat more often during rapid weight loss (around 1 to 2 percent). Risk factors are female sex, older age and a rapid loss of more than 1.5 percent of body weight per week.

In people with diabetic retinopathy, a rapid drop in blood sugar can cause temporary worsening. Always consult your ophthalmologist if you already have retinopathy. Thyroid cancer (medullary type) has been seen in animal studies but has not been shown to be increased in humans; the medicine is, however, contraindicated in people with a hereditary predisposition to MEN2.

What can you do yourself against side effects?

Against nausea: eat smaller meals, avoid fatty and very sweet food, drink enough water, do not lie down straight after eating. Ginger (tea or capsules) helps some people.

Against diarrhoea: drink extra water with electrolytes, temporarily avoid lactose and caffeine, eat soluble fibre (oats, banana, white rice). For diarrhoea lasting longer than 3 days: call your doctor.

Against constipation: increase fibre intake gradually (soluble fibre such as psyllium helps more than coarse fibre), drink at least 2 litres per day, move daily. Consider macrogol sachets as advised by your doctor.

When to see a doctor immediately?

Call your doctor or 112 (the Dutch emergency number) for: severe abdominal pain radiating to the back, persistent vomiting where you cannot keep anything down, black or bloody stools, palpitations or fainting, yellow skin or eyes (jaundice), allergic reaction with swollen lips, tongue or throat, severe pain in the upper right abdomen (gallbladder).

Call within 24 hours for: diarrhoea or vomiting lasting longer than 3 days, signs of dehydration (dizziness, dark urine, dry mouth), unexplained severe fatigue, sudden visual disturbances.

Monitoring at Go Leaner

At Go Leaner you have blood tests at the start (kidney, liver and thyroid function, HbA1c, glucose, lipase) and an intake consultation with a BIG-registered doctor. This is followed by monitoring every 3 months during the titration phase and every six months during maintenance.

You have unlimited access to our team via the app and receive an answer to questions within 24 hours. If a side effect is severe or persistent, we adjust the dose or switch to an alternative medicine at no extra cost.