Semaglutide: what it is and which brands are available in Spain

What is semaglutide and how does it work?

Semaglutide activates the receptor for glucagon-like peptide-1, or GLP-1, a hormone released by the gut when you eat. This signal plays a part in feelings of fullness and the body’s response to glucose. When glucose rises, it encourages insulin release. It also slows stomach emptying and reduces appetite, according to the European product information [1] [2] [3].

That is why a usual portion may start to feel large. This feeling does not tell you what your body needs, and it is one of the questions we hear most often in appointments. When someone tells us about it, we look at what they eat throughout the day, how they feel and whether they are maintaining their strength.

The molecule is the same in its different formulations. The authorised use, route of administration and prescribed regimen vary. The pen is injected under the skin; the tablet is taken by mouth. Having the same active ingredient does not make their doses equivalent [1] [2] [3].

For an overview of this group of treatments, see our guide to GLP-1 medicines. It explains how they relate to other medicines and to nutritional follow-up.

Which semaglutide brands are available in Spain?

Ozempic is a once-weekly injection authorised for adults with inadequately controlled type 2 diabetes. It is used alongside diet and physical activity. Our Ozempic guide explains its conditions of use and safety [1].

Rybelsus is semaglutide in tablet form for adults with type 2 diabetes. Its absorption by mouth depends on specific instructions for taking it. This changes how it is taken, but does not mean that milligrams in a tablet can be converted into milligrams in a pen. Find the details in our Rybelsus guide [2].

Wegovy is authorised for weight management in people who meet medical criteria. It is available as a once-weekly pen and a daily tablet; the tablet was authorised in the European Union in July 2026 and for adults only [3]. Our Wegovy guide covers the pen, while the oral Wegovy guide covers the tablet.

The authorised use and funding are separate questions. Ozempic and Rybelsus are funded for type 2 diabetes only in certain circumstances and with prior authorisation from the medicines inspectorate. Wegovy is not funded by Spain’s National Health System, according to the official search tool from the Ministry of Health [4]. Conditions are set for each pack and may change.

There is no single price for the molecule. It depends on the product and its formulation. The comparison cards show the current retail price. If you have a prescription, confirm the formulation and its conditions with the prescriber and the pharmacy.

If you take warfarin or acenocoumarol (Sintrom), the semaglutide product information recommends more frequent INR monitoring when starting treatment, because low INR cases have been reported with acenocoumarol [1]. It is not expected to reduce the effect of oral contraceptives [1]. For Rybelsus, the product information also describes an increase of around 33% in levothyroxine exposure and advises considering thyroid monitoring [2]. Always discuss this with the person who prescribes your medicine.

The brand tells you how the medicine is supplied and what it is authorised for; your medical assessment determines whether any option is suitable for you.

What do semaglutide trials show?

A clinical trial compares groups under defined criteria. Its results are averages, not a prediction for someone who has been prescribed the medicine. Diabetes and weight management are also studied in different populations, so their figures should not be mixed.

In the STEP 1 trial, people without diabetes who received weekly injectable semaglutide alongside lifestyle changes lost an average of 14.9% of their initial body weight after 68 weeks. The placebo group, which received the same lifestyle support, lost 2.4% [5]. This comparison shows the effect in that trial, not what will happen in any one case.

In SUSTAIN 1, which involved adults with type 2 diabetes, glycated haemoglobin, a measure of blood glucose over recent months, fell by 1.45 percentage points with one of the doses studied and 1.55 with the other after 30 weeks. It fell by 0.02 points with placebo [6]. This is a different clinical question from weight loss.

In OASIS 4, oral semaglutide 25 mg for weight management was associated with an average weight loss of 13.6% after 64 weeks, compared with 2.2% with placebo. Both groups received lifestyle support [7]. If we estimate what would have happened had everyone taken the treatment as intended, the figure rises to 16.6% [7].

These trials did not directly compare the four brands with one another. Nor can the percentage from a group without diabetes be applied to someone with type 2 diabetes. Our guide to the differences between Ozempic, Wegovy and Mounjaro separates the molecule, authorised use and formulation.

Lean mass includes muscle, water and other tissues. It may fall during weight loss; measuring it does not show how much muscle function has been lost. Eating enough and doing strength training are part of the support recommended during these treatments by four scientific societies in lifestyle medicine, nutrition and obesity [8]. Our guide to protein and muscle with GLP-1 explains how to put this into practice day to day.

When will generic semaglutide be available?

In Europe, the main protection for semaglutide runs until 2031 through supplementary protection certificates, according to a patent analysis published in 2026 [9]. In Canada, China, India and Brazil, that protection ended in 2026, so competitors can enter those markets [9].

The end of that protection does not set a date for a generic to arrive in Spain. Other patents on formulations and doses remain in force, and authorisation and actual supply are also needed [9]. For that reason, we cannot predict a price or launch date. Our guide to the semaglutide patent and generics follows this closely.

If you see semaglutide offered on social media or websites without safeguards, speak to your pharmacist. The European Medicines Agency has warned of a sharp rise in illegal products advertised as GLP-1 medicines online [10]. Do not use a product of uncertain origin or stop a prescribed regimen to replace it with another product.

What should you eat if you take semaglutide?

With a smaller appetite, a small meal can still be complete. You could start with a protein-rich food, add vegetables or another source of fibre, and include a portion of carbohydrates to suit your circumstances. You do not need to copy someone else’s plan. A weekly menu during GLP-1 treatment offers ideas that can be adapted in an appointment [8].

If your usual portion makes you feel sick, having smaller meals more often may make them easier to tolerate. Drink regularly and discuss persistent symptoms with the person who prescribes your medicine. Nutritional follow-up does not replace a medical review of side effects.

What we see in appointments

A common question is whether it is enough simply to eat much less. In appointments, we see that skipping meals leaves little room for protein, fibre and fluids. We review the whole eating plan, strength and changes in appetite. The aim is to help you eat without turning every mouthful into an obligation.

Another common question is, “I know lots of people who inject it; what do you think?” We understand the curiosity, but the decision to use semaglutide belongs to you and your doctor. We can help you organise meals and movement if there is already a medical indication.

If you have or have had an eating disorder, tell your doctor before starting. An international expert consensus recommends assessing this history in everyone before starting a GLP-1 medicine [11]. At Alimmenta, we address this together with our Psychology team.

Your first step this week

Review your meals. For seven days, note whether your reduced appetite leads you to miss a meal without a source of protein. Take your notes to your next appointment with your doctor or dietitian.

If you are looking for support with adapting your diet and strength training to treatment, find out about our GLP-1 nutritional support. We do not prescribe or change your dose: prescribing and any adjustments remain your doctor’s responsibility.