Wegovy Side Effects

Most common side effects

Wegovy contains the same active substance as Ozempic (semaglutide), but at a higher dose (up to 2.4 mg). As a result you see similar side effects, but on average somewhat more often and somewhat more intense than with Ozempic up to 2 mg.

In the STEP-1 and STEP-4 studies, participants reported: 44 percent nausea, 30 percent diarrhoea, 24 percent constipation, 24 percent vomiting, 20 percent abdominal pain, 15 percent headache. These are cumulative percentages over a treatment period of 68 weeks.

Important: most side effects occur during the titration phase (first 16-20 weeks). In the maintenance phase they are usually mild and stable.

Side effects per dose

0.25 mg and 0.5 mg (titration phase): mainly mild nausea, occasional diarrhoea or constipation. Most people tolerate these doses well.

1 mg and 1.7 mg: side effects become more noticeable, especially in the week of a dose increase. Staying an extra week on the same dose often helps.

2.4 mg (maintenance dose): side effects are most pronounced here. Once you stabilise on this dose, symptoms usually ease to an acceptable level within 4 to 8 weeks.

Hair loss and skin changes

Temporary hair loss (telogen effluvium) occurs in around 3 percent of Wegovy users. It is not the medicine itself that causes hair to fall out, but the rapid weight loss and stress on the body. Recovery almost always follows within 6 months.

Tips: make sure you get enough protein (1.2 to 1.6 grams per kilogram of body weight per day), iron, zinc and biotin. A multivitamin is advisable during strong calorie restriction.

Skin changes as a result of rapid weight loss (loose skin) are not a side effect of Wegovy itself but of the weight loss. This mainly plays a role with >20 percent weight loss.

Gallstones and pancreatitis

Rapid weight loss increases the risk of gallstones: the liver produces more cholesterol-rich bile, which forms stones more easily. In Wegovy studies, 1.6 to 2.4 percent of users developed gallbladder problems (inflammation or stones requiring intervention).

Pancreatitis (inflammation of the pancreas) is rare: fewer than 0.5 percent in clinical studies. Severe radiating abdominal pain is the warning sign.

To reduce these risks, at Go Leaner we aim for a controlled loss of 0.5 to 1 kg per week (no more than 1.5 percent of body weight), adequate hydration and monitoring of liver and gallbladder function.

What can you do yourself?

Against nausea: eat often, small and not too fatty; avoid alcohol; drink ginger tea; sit upright after meals. Avoid large portions on injection day.

Against diarrhoea: electrolyte drinks (ORS), BRAT foods (banana, rice, apple sauce, toast), temporarily avoid coffee, alcohol and lactose. If it lasts longer than 3 days: call your doctor.

Against constipation: more fibre (psyllium, linseed), at least 2 litres of water, a daily walk, macrogol sachets if necessary.

Against fatigue: make sure you get enough protein, quality sleep and strength training to preserve muscle mass during weight loss.

When to see a doctor immediately?

Call 112 (the Dutch emergency number) or go to the emergency department for: severe radiating abdominal pain (pancreatitis), pain under the right rib cage with fever (gallbladder), blood in stool or vomit, severe allergic reaction, persistent vomiting without being able to keep anything down.

Call your doctor within 24 hours for: signs of dehydration, severe persistent headache, sudden marked loss of vision, jaundice, unexplained palpitations or confusion.