What it is
In the EU, the product authorised for weight management is Wegovy, used together with a reduced-calorie diet and more physical activity. The same active ingredient is also sold as Ozempic, but that is a separate product authorised for type 2 diabetes, not for weight management. Semaglutide has been authorised for use in the EU since 6 January 2022.Active ingredient: semaglutide. Dosage range: 0.25 – 2.4 mg / week.
How it works
Semaglutide is a close copy of GLP-1, a hormone your gut releases after you eat. It shares about 94% of the structure of the natural hormone, so it fits the same docking points on cells, but it is built to last much longer in the body. Once attached to those docking points, it signals the parts of the brain that control hunger, including the hypothalamus and brainstem — in clinical studies people reported feeling full sooner, staying full for longer, feeling less hungry, and having fewer and weaker food cravings. Because appetite falls, most people take in fewer calories without consciously trying, and that gap is what produces weight change over months. Semaglutide also slightly slows how fast the stomach empties early after a meal, and prompts insulin release only when blood sugar is high.Receptor-level mechanism
Semaglutide is a GLP-1 receptor agonist. It binds to and activates the same GLP-1 receptor that the endogenous hormone targets. At the pancreas, this activation potentiates glucose-dependent insulin secretion from beta cells — insulin is released only when blood glucose is elevated, which is why semaglutide carries a low intrinsic risk of hypoglycaemia. It also suppresses glucagon release from pancreatic alpha cells, further reducing hepatic glucose output. In the gut, GLP-1 receptor activation slows gastric emptying via vagal signalling, which delays nutrient absorption and contributes to postprandial satiety. In the central nervous system, semaglutide acts on GLP-1 receptors in the hypothalamus (arcuate nucleus, paraventricular nucleus) and brainstem (area postrema, nucleus tractus solitarii) — regions that integrate appetite and energy-balance signals. The net effect is reduced hunger, increased fullness, and fewer food cravings.1
Weeks 1–4
Lowest dose.
2
Weeks 5–16
Step up gradually.
3
Month 4+
Maintenance dose.
4
Ongoing
Regular check-ins.
What the studies reported
STEP 1 (N Engl J Med 2021;384(11):989-1002, ClinicalTrials.gov NCT03548935) is the pivotal trial behind the EMA’s Wegovy assessment. It was a double-blind, randomised, placebo-controlled trial that enrolled 1,961 adults with a BMI of 30 or greater (or 27 or greater with at least one weight-related comorbidity) and assigned them in a 2:1 ratio to once-weekly subcutaneous semaglutide 2.4 mg or placebo for 68 weeks, both added to lifestyle intervention. Everyone also followed a reduced-calorie diet and increased physical activity. People with type 2 diabetes were excluded, and the study measured weight only up to week 68, so longer-term maintenance and cardiovascular outcomes were not assessed in this trial. The coprimary endpoints were the percentage change in body weight and the proportion of participants achieving at least 5% weight reduction, both assessed using a treatment policy estimand (which evaluates effects regardless of treatment discontinuation or rescue interventions).What has been reported
Figures below are from the pooled STEP 1–4 phase 3 programme assessed by the EMA, semaglutide 2.4 mg versus placebo.
5.7% of people on semaglutide 2.4 mg stopped treatment because of side effects, versus 3.0% on placebo — mostly because of stomach and bowel symptoms.
Interactions and contraindications
A doctor weighs several conditions before prescribing semaglutide. The medicine should not be used in people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2 (MEN 2), because GLP-1 receptor agonism can promote C-cell proliferation. It is contraindicated during pregnancy, planned pregnancy in the next 2 months, and breastfeeding. Semaglutide is also not advised after pancreatitis or in active pancreatic disease, in people with type 1 diabetes (its mechanism requires functional beta cells), or in those with severe gastroparesis or chronic severe gastrointestinal disease. Because semaglutide delays gastric emptying, it may reduce the rate of absorption of oral medicines taken at the same time, particularly those that require rapid onset. The reviewing doctor checks for concomitant use of insulin or sulfonylureas, as the combination can raise the risk of hypoglycaemia.How Hi-Doctor handles it
It’s prescribed alongside changes to diet and activity, as part of a medically supervised plan — a licensed EU doctor decides whether it’s appropriate and safe for you. Our doctors review every weight-loss option and recommend what fits your history and goals. See the Wegovy page for the specific EU-authorised product and its injection and dosing guide, how it works for the consultation process, and pricing for the consultation fee.Start a consultation
Weight-loss consultation
Answer the weight-loss questionnaire and a registered doctor reviews it.
They decide whether treatment is appropriate, which one, and at what dose —
and declining is a normal outcome. See what it costs
and how the review works.