GLP-1 weight loss injections: Ozempic vs Wegovy vs Mounjaro

In Spain, 2.84 million packs of GLP-1 medicines were dispensed between January and August 2024—around 50% year-on-year growth according to IQVIA data. The trajectory points towards the US scenario, where 12% of the adult population already uses GLP-1 medicines. This guide explains—using pharmacist-led criteria—what these medicines are, how they differ, what you can obtain in a Spanish pharmacy with a prescription, and which non-prescription options can genuinely help with weight management.

What are GLP-1 medicines and why are they working so well

A GLP-1 medicine is a drug designed to mimic the gut hormone GLP-1 (glucagon-like peptide-1), helping you feel fuller, eat less and slow gastric emptying. When you eat, your intestine releases hormones (incretins) that tell the brain “stop—you’ve had enough”. The key one is GLP-1. In people living with obesity this signalling can fail: what recent literature calls food noise can appear—constant mental chatter about food, persistent thoughts about what to eat and when. GLP-1 medicines are synthetic molecules that imitate this natural hormone: they activate the same receptors in the brain, reduce appetite, slow gastric emptying and, in many people, make that mental noise fade.

What’s most interesting isn’t only weight loss. Psychiatrist Nora Volkow has documented that these medicines dampen the brain’s reward-system response—the same circuitry activated by substances such as nicotine or alcohol. That’s why they’re now being studied for other addictions too: obesity and dependency share more brain pathways than we used to think.

GLP-1 medicines available in Spain (Ozempic, Wegovy, Mounjaro, Saxenda)

At present, Spanish pharmacies dispense four injectables and one tablet—all prescription-only medicines. Ozempic (semaglutide, once-weekly injection) is licensed for type 2 diabetes and is the best-known publicly; at diabetes doses, published data place weight loss at around 5–10% when used off-label, not at the obesity-trial figures. Wegovy is the same molecule as Ozempic (semaglutide) but with dosing and presentation specifically for obesity treatment: here, weight losses of 15–17% at 68 weeks have been reported in the STEP programme. Mounjaro (tirzepatide) is the newest and most potent option: a dual GLP-1 + GIP agonist, with 20–22% weight loss at 72 weeks reported in the SURMOUNT programme. Saxenda (liraglutide) is the long-standing anti-obesity option: more modest losses (5–10%) and poorer adherence because it requires daily injections rather than weekly.

For diabetes there is also Rybelsus, the first oral semaglutide. Only around 2% of the swallowed dose is absorbed, so its potency is lower than injectable versions. In the near future we expect orforglipron (another next-generation oral GLP-1 with better absorption) and retatrutide—a triple agonist (GLP-1 + GIP + glucagon) with up to 30% losses in early trials. This market moves quickly.

How to get a prescription for GLP-1 medicines in Spain

These five medicines are prescription-only. Without a valid prescription they cannot be supplied by a Spanish pharmacy. The three usual routes to obtain one are: your GP or endocrinologist within the Spanish National Health System (SNS) (if you meet criteria such as obesity with BMI ≥30 or ≥27 with comorbidities like hypertension, diabetes or sleep apnoea), a private endocrinologist specialising in obesity (faster access and closer follow-up—worth considering if you value strict clinical support), or an online platform offering a regulated medical consultation (often cheaper but you should verify there are identifiable registered doctors and genuine follow-up—not just rapid prescription issuance). Once you have a valid prescription you can attend any pharmacy for dispensing. The SNS does not fund these medicines for obesity (it does for diabetes), so payment is private in most cases.

The monthly cost of any of these medicines sits in the mid-to-high range of private medicine spend and typically needs to be sustained for months. For many people, cost is the real barrier.

Side effects and who it suits (and who it doesn’t)

GLP-1 medicines work—but they’re not benign. Common side effects (more than 10% of users) include: nausea and vomiting; constipation or diarrhoea; reflux/heartburn; tiredness; dizziness. They tend to be worse in the first weeks or when increasing dose. A key medium-term risk is loss of muscle mass associated with rapid weight loss if it isn’t paired with resistance training and adequate protein intake. Less common but serious risks include pancreatitis, gallbladder problems and gastroparesis. These justify close medical follow-up.

These medicines are designed for people with clinical obesity (BMI ≥30) or overweight (BMI ≥27) with medical comorbidities. The indication is NOT to lose the last 4–5 kg before a wedding. Without specific medical assessment they should not be used by people with a history of pancreatitis; a family history of medullary thyroid carcinoma; pregnancy or breastfeeding; pre-existing gastroparesis; or active eating disorders. Under 18s require very specific paediatric indications.

If you start treatment, there are three rules your endocrinologist will explain—but it helps to know them upfront: prioritise protein (around 1.2–1.5 g/kg body weight per day), drink plenty of fluids (roughly 2–2.5 litres), and make resistance training non-negotiable 2–3 times per week. Without strength stimulus, weight loss comes with muscle loss—and you end up lighter but weaker.

The non-prescription alternative that’s working best

If you can’t access a prescription, don’t meet clinical criteria for injectables or want to start with a gentler option before considering medication, pharmacies do stock food supplements that can help appetite control and support satiety without needing a prescription. They are not direct substitutes for injectable GLP-1 medicines (their effect size is smaller and they don’t sit under the same regulatory framework), but they can fit very well for mild-to-moderate overweight where you want dietary support without injections, without significant side effects and without strict clinical monitoring.

Across the catalogue, the option performing best is Kobho GLP. It’s a food supplement pack (drinkable vials + capsules) with a well-studied formula: phytosome berberine (Berbevis®), calcium butyrate, epigallocatechin gallate (EGCG), resveratrol, chlorogenic acid, fucoxanthin, forskolin, chromium, ginseng and spirulina. Each active targets a different mechanism (satiety signalling, microbiota support, glucose metabolism, fat oxidation), and it’s the combination that explains real-world performance compared with single-ingredient pharmacy options. In my experience as a pharmacist in Spain (registration number 1383), when someone asks me for a non-prescription alternative to Ozempic, Wegovy or Mounjaro, this is the one I point them to.

Kobho GLP Pack 30 Vials + 90 Capsules

Food supplement in vials + capsules with phytosome berberine (Berbevis®), calcium butyrate, EGCG, fucoxanthin, forskolin, chromium, ginseng and spirulina. Supports satiety and appetite control without a prescription.

Final pharmacist recommendations

GLP-1 medicines are an important tool with unprecedented results in pharmacological obesity treatment. But they are serious medicines that require prescribing oversight, close clinical follow-up and sustained commitment. They’re not magic—and they’re not a short course that “fixes” obesity forever: when treatment stops, most people regain a significant proportion of lost weight unless real lifestyle changes are maintained.

If you meet clinical criteria (obesity or overweight with comorbidities), your best first step is to speak with your usual doctor or an endocrinologist. Self-prescribing via platforms with lax follow-up isn’t wise—even if access looks easy. If you don’t meet criteria—or you don’t want to or can’t access medication—non-prescription supplementation has a genuine place. My main pharmacy recommendation is Kobho GLP, due to its robust composition (phytosome berberine Berbevis®, calcium butyrate, EGCG, fucoxanthin, forskolin, chromium, ginseng and spirulina) and the results I’m seeing in people with mild-to-moderate overweight. I’ve analysed it in detail in the full pharmacist review of Kobho GLP.

Whichever route you choose, three things are non-negotiable: enough protein to protect muscle mass; regular resistance training; and medical advice before any pharmacological decision. Weight loss done properly is what still holds at two years—not what shows on the scales by month three.

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