Ozempic or Wegovy – what is the difference for weight loss?

How does GLP-1 work (Ozempic and Wegovy)?

GLP-1, or glucagon-like peptide-1, is an endogenous hormone that plays a central role in regulating both blood sugar levels and appetite. In connection with a meal, GLP-1 is released from the intestine and stimulates the pancreas to increase glucose-dependent insulin secretion, which helps lower blood sugar – an important mechanism in the treatment of type 2 diabetes. Simultaneously, GLP-1 affects central appetite-regulating areas in the brain as well as the motility of the gastrointestinal tract, leading to increased feelings of satiety, decreased energy intake, and reduced food cravings.

Ozempic and Wegovy contain semaglutide, a GLP-1 receptor agonist that mimics the effect of the natural hormone. In clinical studies, treatment with semaglutide has shown significant effects on both weight reduction and glycaemic control. With dosage adapted for obesity treatment, an average weight loss of around 15 percent of body weight has been reported after approximately one year of treatment, in combination with lifestyle support.

Treatment with GLP-1-based medications is usually administered as a subcutaneous injection once a week. For optimal effect, medical treatment should be integrated with structured lifestyle measures, including dietary changes and regular physical activity.

The same active substance

Ozempic and Wegovy contain the same active substance, semaglutide, but differ in terms of dosage regimen, approved indication, and treatment purpose. Ozempic was primarily developed and approved for the treatment of insufficiently controlled type 2 diabetes, while Wegovy is specifically approved for the treatment of obesity and weight management.

Both medications are developed by Novo Nordisk and contain the same active substance, semaglutide. By activating GLP-1 receptors, the medication affects several physiological mechanisms:

• Suppresses appetite by influencing the brain's appetite-regulating centres
• Increases and prolongs the feeling of satiety
• Delays gastric emptying
• Stimulates glucose-dependent insulin release and inhibits glucagon secretion

The difference between the products lies in their regulatory approval:

• Ozempic is approved for the treatment of people with insufficiently controlled type 2 diabetes, as a supplement to diet and physical activity.
• Wegovy is approved specifically for weight management in adults with obesity (BMI ≥30 kg/m²) or overweight (BMI ≥27 kg/m²) in combination with at least one weight-related comorbidity, such as hypertension, dyslipidaemia, or type 2 diabetes. The medical treatment serves as a supplement to lifestyle changes in diet and physical activity.

In addition to the indication, the products also differ in dosage regimen, where Wegovy is approved for higher doses of semaglutide than Ozempic, contributing to the higher average weight reduction seen in obesity treatment.

Dosage and effect on weight

Ozempic and Wegovy both contain semaglutide but differ in approved indication and dose levels.

• Ozempic is delivered via a pre-filled injection pen and is available in doses of 0.25 mg, 0.5 mg, 1 mg, and 2 mg. Treatment starts with 0.25 mg semaglutide once a week. The dose can then be stepped up gradually to achieve adequate glycaemic control. In studies on diabetics, weight loss has been seen as an additional known pharmacological effect, but the dose in these contexts has been focused on blood sugar control.
• Wegovy is delivered via a pre-filled injection pen and is available in doses of 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg. Treatment starts with 0.25 mg semaglutide once a week, and the dose can be titrated successively to achieve the lowest effective dose for weight loss. The purpose of titration is to optimize effect while minimizing the risk of gastrointestinal side effects.

The difference in dose levels reflects the different treatment goals. In studies of type 2 diabetes, doses up to 1.0–2.0 mg have primarily been used for blood sugar regulation, while studies in obesity (e.g., the STEP program) have used 2.4 mg to optimize weight reduction. The higher approved dose for obesity treatment is an important factor behind the larger average weight loss reported in these studies.

The mechanism of action is the same for both products, and both medications are given once a week. The dosage is always adjusted individually based on treatment goals, effect, and tolerance.

Side effects – is there any difference?

Since both medications contain semaglutide, the side effect profile is the same. The medication can cause several common side effects, the most frequent of which are linked to the gastrointestinal system:

• Nausea
• Diarrhoea
• Constipation
• Vomiting

Semaglutide delays gastric emptying and affects appetite regulation, which can contribute to gastrointestinal discomfort, especially at the beginning of treatment or in connection with dose increases. In most cases, side effects are mild to moderate and tend to decrease over time as the body adapts.

Vomiting and diarrhoea can in some cases lead to fluid loss. It is therefore important to ensure adequate fluid intake, especially with pronounced symptoms.

In case of persistent, severe, or unexpected side effects, a medical assessment should be made. Regular follow-up during treatment is important to ensure good tolerance and a favourable risk-benefit balance.

Which treatment is right for the patient?

The choice of modern medications for medical weight loss is based on availability, medical assessment, and the person's BMI. At Yazen, doctors always make an individual assessment, as it is necessary to consider several factors that affect the result, such as lifestyle, health, and previous treatments.

Lifestyle changes, including diet and exercise, are crucial for effective treatment of obesity, and better and more sustainable results can be achieved when these are combined with medical treatment. Patients using GLP-1-based medical treatment should be physically active to improve weight loss and maintain muscle mass. Continuous support from healthcare professionals can help patients maintain weight loss in the long term.

There are also other GLP-1-based treatments, such as Mounjaro from Eli Lilly. Mounjaro contains tirzepatide, which acts on both GLP-1 and GIP receptors, and has shown even greater effect on weight loss in people living with obesity and type 2 diabetes in studies.

Yazen works according to the principle of "lowest effective dose," which means the dose is not increased routinely if the patient achieves good effect at a lower level. This reduces the risk of side effects and keeps costs down, regardless of which product is used.

Sources

1. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). The New England Journal of Medicine.
   https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
2. European Medicines Agency (EMA). Ozempic (semaglutide) – EPAR Product Information.
   https://www.ema.europa.eu/en/medicines/human/EPAR/ozempic
3. European Medicines Agency (EMA). Wegovy (semaglutide) – EPAR Product Information.
   https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy
4. Nature Medicine: Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial. https://pubmed.ncbi.nlm.nih.gov/36216945/
5. The New England Journal of Medicine. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity https://www.nejm.org/doi/full/10.1056/NEJMoa2416394