Zepbound and Wegovy are both licensed for weight management. That much is genuinely shared. What is not shared is the substance: official labelling names tirzepatide as the active ingredient in Zepbound and semaglutide as the active ingredient in Wegovy. Two different medicines, approved for the same broad job.
The form is not fully shared either, and this is the part that has changed. Zepbound is an injection given once a week. Wegovy labelling now covers two presentations, an injection given once a week and tablets taken by mouth, so a reader who assumes the two products are alike in how they are taken may be wrong about their own. Your pack and your prescription are the authority on which one you were given.
That is an unusual thing to compare, and it is why this query is so hard to answer well. The purpose lines up, so the products look interchangeable in a headline, while everything underneath the purpose differs. Which one suits a particular person is a clinical decision made against their own history, other medicines, and circumstances, and nothing on this page stands in for the person making it.
What each product actually is
Wegovy is semaglutide. The American regulator publishes its own prescribing document for it, the European regulator authorises it for weight management, and NHS material describes semaglutide as a medicine used alongside diet and physical activity. Its labelling covers the weekly injection and tablets swallowed by mouth, which is why this page keeps sending you back to your own carton.
Zepbound is tirzepatide. It was approved by the American regulator for chronic weight management, and it too has a prescribing document of its own rather than sharing one with anything else. NHS information on tirzepatide describes a once-weekly injection used in obesity as well as in type 2 diabetes.
Both descriptions come from official product material rather than from any comparison between them, and that is deliberate. Regulators assess each product on its own file. They do not publish a league table, and neither does this page.
A shared purpose is not equivalence
It is tempting to reason that two medicines approved for the same thing must be broadly the same. Approval does not work that way. Each product was assessed on its own evidence, carries its own leaflet, has its own list of cautions and interactions, its own device and pack, and its own set of situations in which a prescriber would or would not reach for it.
The practical version of that point is simple. Something you read about one of these products may be entirely true and still tell you nothing reliable about the other. Personal accounts in particular travel badly between the two, because the person writing had their own history and their own reasons for being on what they were on.
Why a European reader may never see one of these names
Across much of Europe, tirzepatide is generally sold under the Mounjaro name rather than as Zepbound, and the European regulator's authorised tirzepatide product page carries the Mounjaro name. A reader in Germany, France, Spain, or the UK who has been following American coverage will meet the Zepbound name constantly online and never once on a local carton.
For those readers the comparison quietly changes shape. The two names actually in front of them are more likely to be Mounjaro and Wegovy, which is the same underlying pair of ingredients wearing a different label on one side. Knowing that saves a lot of pointless searching for a product that is not sold locally under the name you learned first.
Availability also moves. A name absent this year may be present next year, and the reverse happens too. Rather than trusting any page to be current about that, treat your own packaging, your prescription, and your pharmacy as the authority on what you can actually be given.
Access is often what settles it
In practice the question is frequently decided before anyone weighs the medicines against each other. In England, weight management injections are described by NHS England as prescribed through a specified service and pathway rather than supplied on request, and NICE has separately assessed tirzepatide for managing overweight and obesity within a defined pathway. Elsewhere, insurance rules, formularies, and local supply do comparable work.
None of that is a comment on either medicine. It is a description of how people actually arrive at one product rather than the other, and it is worth understanding before you invest much energy in choosing between two options where only one may be reachable.
One record fits either product
Where both of the packs in question are weekly injections, the log you keep does not depend much on which one you end up with. This is genuinely useful if a change happens later: you carry the record forward instead of starting again, and the periods either side of the change stay comparable because you measured the same things throughout.
- The injection date each week, alongside the date you had intended
- The general site used, if you rotate between sites, recorded rather than remembered
- Appetite, fullness, digestion, sleep, and energy, noted on the day rather than summarised weeks later
- Weight measured the same way each time, against your own starting point rather than anyone else's
- The brand name, the active ingredient, the form you were actually given, and the country of supply, copied exactly from the carton
- The date any change was made, kept as its own entry so the two periods never merge into one line
If what you were given under the Wegovy name turns out to be tablets rather than an injection, the site and pen lines have nothing to describe and a timing line takes their place: roughly when the tablet was taken, and roughly when food, drink, or another medicine taken by mouth followed. Whatever conditions attach to taking it are set out in the leaflet supplied with that pack. None of them are repeated here, and a pharmacist is the person to go through them with.
Consumer guidance from the American regulator recommends keeping a personal medication list naming what you take, and these fields are that list with a few dated observations attached. It is the part of this whole subject that is fully within your control, which is more than can be said for which product a service can offer you.
What to bring to the appointment where this is decided
- What the treatment would be for, in your own words, including anything else being managed at the same time
- A current list of every medicine and supplement you take
- Any history that might bear on suitability, including previous treatments and how they went
- The dated notes you have kept, if you are already on something
- The questions you actually want answered, written down, because short appointments compress
Asking a clinician to explain why they would choose one product for you is a far better use of that time than asking them to confirm a preference formed from reading. Their answer is specific to you in a way that no article, including this one, can be.
Why we will not pick one
There is no statement anywhere on this page that either product produces more weight loss, works more quickly, or is easier to live with, and none is implied by what has been left out. Those comparisons depend on individual circumstances and on clinical judgement, and a general page that offered a verdict would be substituting confidence for knowledge about the one question where that costs the most.
For the same reason there are no dose figures here and no way of reading one product across to the other. UK government guidance asks people to consult a healthcare professional before switching from one GLP-1 medicine to another, including between brands containing the same type of GLP-1, and says these medicines vary in how strong they are and in the conditions they can be used for. If you are unsure what you have been prescribed, the leaflet inside the pack and your pharmacist will tell you in moments, and if symptoms are severe or getting worse quickly, urgent medical help comes before any of this.