1. What is it?
Semaglutide is a peptide, a molecule built from linked amino acids. In medicines it acts as the active ingredient, the component responsible for the therapeutic effect. Wegovy, Ozempic and Rybelsus are names of medicines containing the same substance. [56] [57] [58]
Wegovy is used for weight management, while Ozempic and Rybelsus treat type 2 diabetes. The medicines differ in form and approved use. They are not interchangeable products that can be chosen independently based only on the ingredient's name. [55] [57] [58]
2. Why do people turn to it?
The two main goals are better control of type 2 diabetes or treatment of obesity and associated health problems. Interest in weight loss is high because the medicine can make it easier to eat less. Treatment is combined with appropriate nutrition and activity. [55] [57]
Simply wanting to lose a few kilograms does not establish an indication for treatment. Assessment also takes account of height, accompanying conditions, previous treatment and the risk of side effects. Wanting a quick result before a holiday is different from treating a chronic disease. [55]
Who is Wegovy approved for?
For adults: a BMI of at least 30, or at least 27 with one or more weight-related health problems. BMI relates body weight to height. The injectable form is also indicated for adolescents aged 12 or over with obesity and a weight above 60 kg; tablets are intended for adults. [56]
3. How does it work in the body?
It mimics GLP-1, a hormone involved in the body's response to food, and affects hunger and fullness signals. This can reduce the urge to eat and make smaller portions easier. It does not mean the medicine removes every cause of excess weight. [55]
It also helps the pancreas release insulin when blood sugar is high. Insulin allows the body to use sugar from the blood. This explains why the same ingredient is also used to treat type 2 diabetes. [57] [58]
4. What do studies actually show?
Weight loss. In STEP 1, people taking semaglutide with lifestyle-change support lost an average of 14.9% of body weight over 68 weeks. Participants were adults with obesity or overweight plus another health problem, without diabetes. [59]
A 14.9% reduction from a starting weight of 100 kg equals 14.9 kg. This illustrates an average, not a promise for an individual. Participants lost different amounts of weight.
A cardiovascular benefit. The SELECT study found a benefit of semaglutide in reducing the risk of heart attack, stroke or cardiovascular death. Participants already had cardiovascular disease and overweight or obesity, but did not have diabetes. The same benefit cannot be assumed for every healthy person. [60]
More detailed data and study limitations
STEP 1 involved 1,961 people. Participants received lifestyle-change support. The study tested 2.4 mg injections, and its analysis included treatment discontinuation. Digestive symptoms led 4.5% of semaglutide recipients to stop treatment. The dose describes study conditions, not self-treatment instructions. [59]
SELECT: 17,604 people aged 45 or older, with mean follow-up of 39.8 months. In the semaglutide group, heart attack, stroke or cardiovascular death occurred in 6.5% of participants. Adverse effects led 16.6% of semaglutide recipients to stop treatment. [60]
Both studies were funded by Novo Nordisk. We read the authors' summaries in PubMed, not the full articles. [59] [60]
5. What cannot be promised?
A lasting effect after a short course. One year after treatment ended in a STEP 1 subgroup, participants had regained an average of about two-thirds of the weight they had lost. Structured lifestyle support also ended, so the entire change cannot be attributed to stopping the medicine alone. This finding concerns 327 people followed up, not every patient. [61]
The same result for everyone. Results depend on the population studied and the treatment formulation. Average weight loss does not tell us how much a particular person will lose or how well they will tolerate the medicine. [59] [62]
Proven rejuvenation. The studies cited here assessed specific health problems. A benefit in treating obesity or heart disease is not evidence that semaglutide extends the life of every healthy person. This is a limit of what these studies can establish. [59] [60]
6. What are the risks and side effects?
Nausea, vomiting, diarrhoea, constipation and abdominal pain are common. Vomiting and diarrhoea can cause dehydration. Gallstones and pancreatitis are also possible. Severe, persistent abdominal pain requires urgent medical contact. [56]
The EMA recognised NAION, a particular type of optic nerve damage, as a very rare side effect of semaglutide. Sudden loss of sight or rapidly worsening vision requires urgent medical attention. [63]
What should you discuss with a doctor before treatment?
Pregnancy, plans for pregnancy and breastfeeding: semaglutide is not used during pregnancy or breastfeeding. Previous pancreatic disease, problems with stomach emptying and diabetes-related eye complications also matter. Provide a list of all medicines: combining it with insulin or certain diabetes medicines increases the risk of low blood sugar. Before anaesthesia, inform the team about treatment because stomach contents may move more slowly. These are selected important warnings; full information is in the leaflet for the specific medicine. [57] [58]
7. What is its status in Poland and the European Union?
It is an ingredient of legally authorised prescription medicines. Wegovy, Ozempic and Rybelsus hold authorizations valid throughout the EU, including Poland. Drug approval must be distinguished from availability of a particular pack in a pharmacy and reimbursement rules. [55] [57] [58]
Current EMA documentation covers Wegovy pens and tablets; Ozempic is injectable and Rybelsus is a tablet. A shop-bought vial labelled semaglutide is not thereby established as one of these approved medicines. [56] [57] [58]
8. What is new in research?
Selected recent publications and updates. The dates below refer to the sources; this description was last checked on 3 November 2026.
Hunger has returned before the next dose of Ozempic. Can you have the injection early?
The return of appetite is not a reason to add extra injections. We explain the difference between changing the injection day and taking the medicine more frequently.
Semaglutide and muscle: what does the small STEP UP analysis show?
Researchers examined body composition and a simple physical performance test. We explain why a small comparison group limits confidence in the conclusions. [64]
Semaglutide tablets and new safety information
The tablet study showed weight loss but also frequent digestive symptoms. The article also discusses EMA documentation checked in November 2026. [62]
Where does this information come from?
Prepared by Pepto. Uses EMA information and publication abstracts; this is not a comprehensive review of all literature. The material reviewed is specified for each source.
Show sources and how they were checked
- Wegovy
EU regulator · description updated 26.08.2026 · page read. Accessed: 03.11.2026.
- Wegovy: EPAR — Product information
EU regulator · updated 26.10.2026 · selected sections on indications, formulations and safety were read. Accessed: 03.11.2026.
- Ozempic: EPAR — Product information
EU regulator · updated 25 August 2026 · selected sections on indications, formulations and safety reviewed. Accessed: 3 November 2026.
- Rybelsus: EPAR — Product information
EU regulator · updated 22 April 2026 · selected sections on indications, formulations and safety reviewed. Accessed: 3 November 2026.
- Once-Weekly Semaglutide in Adults with Overweight or Obesity
Study publication · online 10 February 2021 · PubMed abstract reviewed; full text not read · DOI: 10.1056/NEJMoa2032183. Accessed: 3 November 2026.
- Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes
Study publication · online 11 November 2023 · PubMed abstract reviewed · DOI: 10.1056/NEJMoa2307563. Accessed: 3 November 2026.
- Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension
Post-trial follow-up publication · 19.05.2022 online · PubMed abstract read · DOI: 10.1111/dom.14725. Accessed: 03.11.2026.
- Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity
Study publication · NEJM issue 18.09.2025 · PubMed abstract read; full text not read · DOI: 10.1056/NEJMoa2500969. Accessed: 03.11.2026.
- PRAC concludes eye condition NAION is a very rare side effect of semaglutide medicines Ozempic, Rybelsus and Wegovy
Safety announcement · 6 June 2025, corrected 13 June 2025 · full page. Accessed: 3 November 2026.
- Effect of Semaglutide on Thigh Skeletal Muscle Volume, Fat Infiltration and Physical Function in People With Obesity: Secondary Analysis of STEP UP
Study publication · online 20 September 2026 · PubMed abstract accessed through a search index; full text not reviewed · DOI: 10.1111/dom.71323. Accessed: 3 November 2026.