Wegovy ingredientes: what is actually in each pen?

The biggest misconception: 'Wegovy and Ozempic are the same thing'

Both contain semaglutide, and people often assume the two products are interchangeable. They are not. Ozempic is licensed by the MHRA specifically for type 2 diabetes management, not for weight loss. Wegovy carries a separate UK licence for weight management in adults with a BMI of 30 or above, or 27 or above alongside a weight-related health condition. The licensed indication shapes how a prescriber can lawfully prescribe it, which matters if you are approaching a regulated pharmacy rather than an unverified seller.

The semaglutide concentration also differs between products: the injection strengths available under the Wegovy licence run from 0.25 mg up to a 2.4 mg maintenance dose, with a newly approved 7.2 mg pen following MHRA authorisation in April 2026. Ozempic uses different dose increments designed for glycaemic control rather than appetite regulation at weight-loss doses. Our comparison of Ozempic and Wegovy ingredients covers this in more detail if you want to go further.

For anyone searching 'Wegovy ingredientes' having seen the product described in Spanish-language sources, you can find a full breakdown of what goes into the UK-licensed formulation on our page covering Wegovy ingredients, which reflects exactly what the MHRA has reviewed. UK supply chain provenance is what matters for safety.

Semaglutide: what the active ingredient actually does inside the body

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist. GLP-1 is a hormone the small intestine releases in response to food; it signals fullness to the brain, slows the rate at which the stomach empties, and plays a role in blood-sugar regulation. If you want to understand more about how this works in practice, our page on the main ingredient in Wegovy explains how semaglutide is engineered to resist the enzyme that normally breaks GLP-1 down within minutes, giving it a half-life long enough for once-weekly dosing.

The NHS medicines page for semaglutide explains the mechanism clearly if you want a patient-level overview from an authoritative source. In the STEP 1 clinical trial (68 weeks, published in the New England Journal of Medicine), adults taking semaglutide 2.4 mg alongside lifestyle changes lost around 15% of body weight on average, trial participants, not a guaranteed outcome for any individual. A prescriber reviews your health history before concluding whether the mechanism is appropriate for you specifically.

You can read more about the medicine as a whole on our semaglutide overview page.

The inactive ingredients in Wegovy injections, and why they are there

A question our prescribers hear most weeks is whether the non-active components in Wegovy could cause problems for people with particular sensitivities. The inactive ingredients in the Wegovy injection are: disodium phosphate dihydrate (a buffering agent that keeps the solution at a pH your tissue tolerates), propylene glycol (a solubiliser), phenol (a preservative that maintains sterility across the multiple doses in a single pen), and water for injections. The solution is clear and colourless.

Phenol is worth a specific note: at the concentrations used in pharmaceutical injections it functions as a preservative and is well within established safety limits, but people with rare phenol hypersensitivity should discuss this with their prescriber. The full excipient list, including exact concentrations, lives in the Wegovy Summary of Product Characteristics on the electronic Medicines Compendium (eMC), the definitive UK reference for anyone who needs the precise formulation detail.

No gluten, no latex, no animal-derived insulin. The pen itself contains a stainless-steel needle, polypropylene and other medical-grade polymers. If you have a documented allergy to any constituent, your prescriber needs to know before treatment begins, that conversation is part of the clinical assessment, not an afterthought.

How the Wegovy tablet's ingredients differ from the injection

Since the MHRA approved oral semaglutide tablets for weight management in June 2026, some people ask whether the pill and the injection share the same formula. They do not. Our Wegovy page covers both forms of the treatment, including how the tablet relies on an absorption enhancer called sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (abbreviated SNAC) to carry semaglutide across the stomach lining into the bloodstream. Without SNAC, oral semaglutide would be digested before reaching circulation. The tablet form requires no refrigeration, which is practically useful for people who travel frequently or simply find fridge storage inconvenient.

The maintenance dose for the tablet (25 mg) looks dramatically higher than the injection's 2.4 mg, but this reflects the absorption challenge of the oral route rather than a higher biological dose, most of each tablet never reaches systemic circulation. Our page covering the inactive ingredients in Wegovy sets out both formulations side by side if the detail is relevant to you.

If you are already established on the weekly injection and considering switching to the tablet, that is a clinical decision made with your prescriber, not something to navigate alone. Eligibility, clinical history, and current dose all factor in. You can find broader context about treatment options on our weight-loss treatment overview, and when you are ready to talk to a clinician, check your eligibility with our prescribers at no cost.