GLP-1 medications have moved from diabetes clinics to mainstream conversation in under a decade. Demand is real and largely European: an estimated 1.6 million UK adults reported using a weight-loss medication between early 2024 and early 2025, and obesity affects roughly 16 percent of EU adults.
This guide covers what these medications are, how they work, who they are approved for in Europe, the efficacy and side effects, and how access differs by country. It is a companion to our hub on fiber and GLP-1 medications, which goes deeper on the dietary side, and to our overview of the European fiber gap, which explains why fiber intake on these medications is a problem before treatment even begins. Here, we focus on the medications themselves.
This is an educational article. It is not medical advice. Decisions about whether to start, stop, or change a GLP-1 medication should be made with a qualified healthcare professional.
What is GLP-1?
GLP-1, or glucagon-like peptide-1, is a hormone produced by specialized cells (called L-cells) in the lining of the small intestine. It is released after eating. The hormone was first identified in 1986 by researchers Jens Juul Holst and Joel Habener.
Native GLP-1 has four main jobs:
It tells the pancreas to release insulin in proportion to the amount of glucose in the blood. It tells the pancreas to suppress glucagon, the hormone that raises blood sugar. It slows the rate at which food leaves the stomach, which lowers post-meal glucose spikes. It signals the brain (specifically appetite-regulating regions of the hypothalamus and brainstem) that the body has eaten and can stop eating.
In healthy physiology this is a finely tuned, short-lived signal: native GLP-1 is broken down within minutes by the enzyme DPP-4. That short half-life is why human GLP-1 itself is not a useful drug. To turn this hormone into a medication, scientists had to engineer molecules that resist breakdown and stay active for hours or days at a time.
The drug class: GLP-1 receptor agonists
A GLP-1 receptor agonist (often abbreviated GLP-1 RA) is a drug that binds to and activates the GLP-1 receptor, mimicking the natural hormone but lasting much longer in the body. The first GLP-1 RA approved in the EU was exenatide in 2006, a twice-daily injection for type 2 diabetes. Six members of the class have been authorized by the European Medicines Agency since.
A separate but closely related drug, tirzepatide, activates two receptors at once: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). Tirzepatide is therefore not a pure GLP-1 RA, but in everyday use the term “GLP-1 medications” is often used to cover both pure GLP-1 agonists and dual agonists like tirzepatide. We do the same here, while flagging the technical distinction where it matters.
The major medications in Europe
The four molecules that dominate the European market today are semaglutide, tirzepatide, liraglutide, and to a lesser extent dulaglutide. Each is sold under different brand names depending on the indication.
Semaglutide (Novo Nordisk)
Semaglutide is sold under three brand names in the EU, each a different formulation of the same molecule:
Ozempic is a once-weekly subcutaneous injection approved for type 2 diabetes. The European Commission granted marketing authorization on 9 February 2018 via the centralized procedure. Doses range from 0.25 mg starter to 2 mg weekly maintenance.
Rybelsus is the once-daily tablet form, also for type 2 diabetes. The CHMP issued a positive opinion on 31 January 2020, with the European Commission marketing authorization following in Q2 2020. It uses a proprietary absorption-enhancing technology to allow oral bioavailability of a peptide drug, the first GLP-1 RA available as a pill. In September 2025, the EMA’s CHMP approved a label update reflecting cardiovascular benefits demonstrated in the SOUL trial, where Rybelsus reduced the composite of cardiovascular death, heart attack, and stroke by 14 percent versus placebo.
Wegovy is the once-weekly subcutaneous injection approved for chronic weight management. The EMA granted marketing authorization on 6 January 2022. The maintenance dose is 2.4 mg weekly, reached over 16 weeks of titration. In December 2025, the European Commission approved a higher 7.2 mg maintenance option (administered as three 2.4 mg injections in a single session) following CHMP positive opinion based on the STEP UP trial.
Tirzepatide (Eli Lilly)
In Europe, tirzepatide is sold under one brand name (Mounjaro) for both indications: type 2 diabetes and weight management. (In the US, Mounjaro is the diabetes brand and Zepbound the weight management brand. The EU uses one name for both.)
The EMA authorized Mounjaro for type 2 diabetes on 15 September 2022. The weight management indication was added in November 2023. It is a once-weekly subcutaneous injection, available in doses from 2.5 mg up to 15 mg. As a dual GIP and GLP-1 receptor agonist, tirzepatide produces greater average weight loss than semaglutide in clinical trials, alongside higher rates of gastrointestinal side effects.
Liraglutide (Novo Nordisk)
Liraglutide is the older, daily-injected member of the family.
Victoza is the type 2 diabetes brand (1.2 to 1.8 mg daily). Saxenda is the weight management brand at 3.0 mg daily, with EU marketing authorization granted on 23 March 2015. Saxenda was the first GLP-1 RA approved for weight management, before semaglutide entered the field. It is also the only one currently authorized in the EU for adolescents aged 12 to 17 with obesity. Liraglutide is increasingly displaced in clinical practice by the more potent and less burdensome weekly options, but it remains in use, particularly where Saxenda has historically been on formularies.
Dulaglutide and others
Dulaglutide (Trulicity), exenatide (Byetta, Bydureon), and lixisenatide (Lyxumia) are also EU-approved GLP-1 RAs, used primarily for type 2 diabetes. They are less prominent in the weight-loss conversation and we will not cover them in detail here.
Who they are approved for
Type 2 diabetes
All GLP-1 RAs and tirzepatide are approved as adjuncts to diet and exercise for adults with type 2 diabetes. They are typically used after metformin, or where metformin is not tolerated. Beyond glucose lowering, two molecules in the class (semaglutide and liraglutide) have demonstrated reductions in major adverse cardiovascular events in patients with type 2 diabetes and high cardiovascular risk.
Chronic weight management
For Wegovy and Mounjaro’s weight management indication, EMA criteria are: a body mass index (BMI) of 30 kg/m² or higher (obesity), or a BMI of 27 to 29.9 kg/m² (overweight) with at least one weight-related comorbidity. Common qualifying comorbidities include type 2 diabetes or prediabetes, hypertension, dyslipidemia, obstructive sleep apnea, and cardiovascular disease.
Cardiovascular risk reduction
Wegovy is also approved in the EU to reduce the risk of major adverse cardiovascular events in adults with established cardiovascular disease and obesity or overweight, based on the SELECT trial. Rybelsus’s label update in September 2025 added cardiovascular benefits in adults with type 2 diabetes at high cardiovascular risk.
What the trials showed
A handful of pivotal trials underpin the modern view of these drugs.
STEP 1 (semaglutide 2.4 mg, no diabetes)
Published in the New England Journal of Medicine in February 2021, STEP 1 randomized 1,961 adults with a BMI of 30 or higher, or 27 with a weight-related comorbidity, to once-weekly semaglutide or placebo for 68 weeks alongside lifestyle intervention. The semaglutide group lost an average of 14.9 percent of body weight, compared with 2.4 percent in the placebo group. Roughly 86 percent of participants on semaglutide lost at least 5 percent of their starting weight, 69 percent lost at least 10 percent, and 50 percent lost at least 15 percent.
SURMOUNT-1 (tirzepatide, no diabetes)
SURMOUNT-1, published in NEJM in 2022, tested tirzepatide at three doses (5, 10, and 15 mg) in 2,539 adults with obesity or overweight without diabetes over 72 weeks. Average weight loss was 16.0 percent at 5 mg, 21.4 percent at 10 mg, and 22.5 percent at 15 mg, compared with 2.4 percent on placebo. At the 15 mg dose, 78 percent of participants lost at least 15 percent of body weight and 63 percent lost at least 20 percent. A three-year follow-up presented at the European Congress on Obesity in 2025 found that 70 percent of treated participants had limited regain (5 percent or less) from their lowest weight, with mean total reduction of 19.4 percent at week 176.
SELECT (semaglutide, cardiovascular outcomes)
SELECT, published in NEJM in late 2023, tested semaglutide 2.4 mg in 17,604 adults aged 45 or older with established cardiovascular disease, BMI 27 or higher, and no diabetes. Over a mean follow-up of nearly 40 months, semaglutide reduced the composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke by 20 percent compared with placebo. This was the first cardiovascular outcomes trial to show benefit in obesity without diabetes.
What real-world data add
Trial weight loss tends to be the ceiling, not the average. A US cohort study of 175 patients in clinical practice found average weight loss of 5.9 percent at three months and 10.9 percent at six months on semaglutide. A larger cohort of 3,389 patients found one-year weight reductions of 5.1 percent for semaglutide and 2.2 percent for liraglutide, with persistent medication coverage and obesity (rather than diabetes) indications associated with better outcomes. The gap between trial and real-world results comes from a mix of titration, adherence, dose, and duration. People who tolerate the medication, reach maintenance dose, and stay on it tend to track closer to the trial averages.
Side effects
The side effect profile of GLP-1 medications is dominated by the gastrointestinal tract, which is unsurprising given that the drugs slow gastric emptying and modulate gut hormones.
Common gastrointestinal side effects
A 2025 network meta-analysis of 39 randomized trials covering 33,354 non-diabetic patients with overweight or obesity found nausea, vomiting, diarrhea, and constipation as the most common adverse events across the class. Compared with placebo, the relative risk of nausea was approximately 2.95 with semaglutide and 2.90 with tirzepatide. Constipation was significantly increased with semaglutide and liraglutide. In STEP 1 specifically, 44.2 percent of semaglutide participants reported nausea (versus 17.4 percent on placebo) and 31.5 percent reported diarrhea.
A separate Bayesian network meta-analysis in patients with type 2 diabetes (48 trials, 27,729 patients) found an overall GI adverse event incidence of 11.66 percent, with nausea most common at 21.5 percent. Tirzepatide had the highest risk for nausea, diarrhea, and dyspepsia in that population, while semaglutide had the highest risk for constipation.
The GI symptoms are typically worst during dose escalation and improve once a stable dose is reached. Slow titration is the standard mitigation. Around 6.5 percent of trial participants discontinue treatment due to adverse events, mostly nausea, vomiting, and diarrhea.
Less common but documented
Beyond the gut, EMA labels list several less common but important adverse effects. Pancreatitis is rare but documented. Gallbladder disease (cholelithiasis and cholecystitis) appears at modestly elevated rates. Diabetic retinopathy progression has been observed in patients with type 2 diabetes undergoing rapid glucose lowering. The EMA’s Pharmacovigilance Risk Assessment Committee concluded in 2025 that non-arteritic anterior ischemic optic neuropathy (NAION) is a very rare side effect across the semaglutide medicines.
Lean mass changes
GLP-1 medications cause weight loss, and any meaningful weight loss reduces both fat and lean tissue. In the STEP 1 dual-energy X-ray absorptiometry (DXA) subset, lean mass loss accounted for roughly 40 percent of total weight loss. In the SURMOUNT-1 DXA subset, the figure was around 26 percent. A 2024 network meta-analysis across 22 trials put the class average around 25 percent of weight loss as lean mass.
The clinical interpretation matters here. The percentage of total body weight made up of lean tissue is largely unchanged after treatment. This is consistent with normal physiologic adaptation to weight loss rather than pathological muscle wasting. Strategies that protect lean mass during weight loss are not unique to GLP-1 use: adequate protein intake (commonly cited around 1.2 to 1.6 g per kg of body weight) and resistance training. Liraglutide can show a higher lean-mass fraction in some studies, which is one reason newer agents have largely displaced it.
Dosing and titration
All GLP-1 medications use stepwise dose escalation to manage gastrointestinal tolerability. The pattern is the same: start low, hold each dose for several weeks, increase only if the previous dose is tolerated.
For Wegovy, weekly doses go 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, 2.4 mg, with four-week intervals between increases. Reaching the 2.4 mg maintenance dose takes 16 weeks. The newer 7.2 mg high-dose option (EU-approved December 2025) is administered as three 2.4 mg injections in a single weekly session.
For Mounjaro, weekly doses start at 2.5 mg, with 2.5 mg increments after at least four weeks at each dose, up to a maximum of 15 mg.
Saxenda (liraglutide) is daily and titrated weekly from 0.6 mg to 3.0 mg over five weeks. Ozempic for diabetes starts at 0.25 mg weekly and can go up to 1 mg or 2 mg. Rybelsus (oral semaglutide) starts at 3 mg daily for 30 days, then 7 mg, with the option to escalate to 14 mg, and must be taken on an empty stomach at least 30 minutes before any food or other oral medication.
What happens when you stop
This is the question where intuition and evidence diverge most sharply. The intuition is that medication-assisted weight loss should be a finite course of treatment. The evidence is that obesity behaves like a chronic disease, and stopping the medication generally reverses most of the benefit.
The STEP 1 trial extension followed 327 participants for one year after they stopped semaglutide and lifestyle intervention at week 68. Within that year, the semaglutide group regained 11.6 percentage points of body weight, leaving net loss of 5.6 percent (compared with 0.1 percent in the placebo group). That is roughly two-thirds of the prior weight loss regained, alongside a reversal of cardiometabolic improvements toward baseline.
A real-world analysis of 20,274 patients who lost at least five pounds on semaglutide found that 17.7 percent regained all the lost weight or more within a year of stopping. STEP 4 told a similar story with a different design: participants who switched to placebo after 20 weeks of semaglutide regained 6.9 percent of weight, while those who continued lost an additional ~7.9 percent.
These findings have shifted clinical framing toward chronic-disease management. For people who want or need to come off the medication (whether for cost, side effects, or planning a pregnancy), the planning question is no longer “did the drug work” but “how do we maintain the benefits without the drug.” That is a separate body of literature, with diet, training, and post-discontinuation support all playing roles.
Access and reimbursement across Europe
All GLP-1 medications discussed here are authorized centrally by the EMA through the centralized procedure: a single approval valid across all EU member states plus the EEA. But authorization is not access. Reimbursement is decided at national level, by health technology assessment bodies and national insurance systems. The picture varies significantly by country.
Germany
Wegovy launched in Germany in July 2023. Novo Nordisk priced it at €301.91 for four weeks at the maintenance dose (with the full range across doses falling between €170 and €300 per month). Crucially, German statutory health insurance (GKV) does not cover weight-loss medications. Section 34 of the Fifth Social Code (SGB V) classifies them as “lifestyle medications.” Patients pay out of pocket. Ozempic for type 2 diabetes is reimbursed normally through GKV.
United Kingdom
Wegovy launched on the NHS on 4 September 2023, restricted to specialist weight management services in line with NICE guidance TA875. NICE eligibility requires a BMI of at least 35 with weight-related comorbidities, or 30 to 34.9 in specific circumstances. Lower BMI thresholds (typically 2.5 kg/m² lower) apply to people of South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean family backgrounds.
NICE published TA1026 on tirzepatide for weight management on 23 December 2024. NHS England began phased rollout in March 2025 through specialist services, expanding to primary care from June 2025. The full rollout is scheduled across 12 years, prioritizing those with greatest clinical need first. Cohort 1 (BMI of 40 or more plus four or more qualifying comorbidities) is eligible in year one. NHS prescription charges are £9.90 per item in England (free in Scotland, Wales, Northern Ireland). Private prescriptions for Wegovy typically run £165 to £325 per month.
France
GLP-1 medications are EMA-authorized and prescribable, but Wegovy is not currently reimbursed by Assurance Maladie for weight management as of early 2026. Saxenda may be partly reimbursed in cases of severe obesity with comorbidities. HAS (Haute Autorité de Santé) sets the coverage frameworks. Most patients accessing Wegovy for weight management do so privately.
Spain
Spain is similar to France: GLP-1 medications are available but generally not covered by the public system for weight management. Patients pay full cost unless treatment is for type 2 diabetes. AEMPS regulates the medicines and the Ministerio de Sanidad sets policy.
Other markets
In the Netherlands, list prices are around €272 per month for Wegovy and €408 per month for Mounjaro. The US is the global outlier on price: Wegovy lists at $1,349 per package per month, Mounjaro at $1,023, with a network of cash-pay subscription programs softening the headline figure but not bringing it close to European levels.
A note on fiber
Constipation is one of the most consistently reported side effects of semaglutide and liraglutide, affecting roughly one in six users in self-reported community data and showing significant elevation versus placebo in clinical trials. The mechanism is straightforward: slower gastric emptying combined with substantially reduced food intake means less bulk and fluid moving through the gut, and harder, less frequent stools.
The European Food Safety Authority recommends 25 g of dietary fiber per day for adults, an amount EFSA’s NDA Panel concluded is “adequate for normal laxation.” National guidelines are often higher: Germany’s DGE and France’s ANSES both recommend 30 g per day, as does the UK’s SACN. Average European intake falls well below either target, with men typically eating 18 to 24 g per day and women 16 to 20 g.
The implication for GLP-1 users is practical rather than dramatic. People starting these medications often eat substantially less, and unless they pay attention to fiber and fluid, intake can fall well below the threshold needed for normal bowel function. We have a dedicated guide on GLP-1 constipation, causes, and solutions that goes into the specifics. The brief version: enough fiber, enough water, and enough movement, with attention to which fiber types are easiest to tolerate at low food intake.
What this guide does not cover
This is a comprehensive overview, not a complete one. Several adjacent topics deserve their own treatment and we cover them separately on the site: head-to-head comparisons of specific drugs, country-by-country supplement and product roundups, the cardiovascular and kidney evidence in depth, and the discontinuation question (what to actually do if you are coming off a GLP-1).
For decisions about your own treatment, talk to your GP or specialist. EU summary product information for each medication is published by the European Medicines Agency. National regulators (BfArM in Germany, ANSM in France, AEMPS in Spain, MHRA in the UK) publish locally relevant safety updates.
For the dietary side of GLP-1 use, our hub post on fiber and GLP-1 medications is the place to start.