The Wegovy Tablet is a once-daily oral tablet containing semaglutide, while Mounjaro is a once-weekly injection containing tirzepatide. The biggest practical differences are the form (a daily tablet with strict timing rules versus a weekly injection) and the mechanism (Mounjaro acts on two gut-hormone receptors, the Wegovy Tablet on one).
Both are prescription-only weight-management medicines available in the UK only after a clinical consultation with a GPhC-registered prescriber. Neither is "better" for everyone — the right choice depends on your health, preferences and what a prescriber judges to be clinically appropriate. This guide explains how they compare so you can have an informed conversation.
Quick comparison at a glance
| Feature | Wegovy Tablet | Mounjaro injection |
|---|---|---|
| Active ingredient | Semaglutide (oral) | Tirzepatide |
| How it works | Single receptor: GLP-1 agonist | Dual receptor: GLP-1 and GIP |
| Form & frequency | Once-daily tablet | Once-weekly self-injection |
| Dose range | 1.5mg → 25mg (maximum) | 2.5mg → 15mg (maximum) |
| Trial weight loss | 16.6% over 64 weeks (OASIS 4, 25mg) | 22.5% over 72 weeks (SURMOUNT-1, 15mg) |
| Price | from £115/month | from £160/month |
The trial figures above come from separate studies, not a head-to-head comparison, so they cannot be directly compared. Individual results vary; not everyone reaches this.
How each medicine works
The Wegovy Tablet contains semaglutide, a GLP-1 receptor agonist. It mimics a natural gut hormone that controls appetite, so you feel fuller sooner and for longer, and the stomach empties more slowly. It is the same active medicine found in the Wegovy injection, simply taken as a once-daily tablet.
Mounjaro contains tirzepatide, which activates two gut-hormone receptors at once — GLP-1 and GIP. This dual action is what distinguishes it from single-receptor GLP-1 medicines.
Both work alongside — not instead of — lifestyle changes such as diet and physical activity. They are tools to support appetite control, not a cure for obesity.
Taking them day to day
The Wegovy Tablet: timing matters
The Wegovy Tablet is taken first thing in the morning on an empty stomach, with only a small sip of plain water. You then wait at least 30 minutes before eating, drinking anything else, or taking other medicines.
This rule is critical: taken with food, the tablet is far less effective. If a consistent morning routine suits you and you prefer to avoid needles, a daily tablet may appeal — but the timing discipline is essential.
Mounjaro: once a week
Mounjaro is a once-weekly self-injection given under the skin, on the same day each week, with or without food. Many people find one weekly step easier to remember than a daily routine, and there are no empty-stomach rules.
Injecting is straightforward with modern pens, but for some the idea of self-injection is a barrier. This is a genuine personal preference to raise at consultation.
Dosing and titration
Both medicines start low and increase gradually. This step-up approach — called titration — gives your body time to adjust and helps reduce side effects.
- Wegovy Tablet: 1.5mg starter → 4mg → 9mg → 25mg maintenance (the maximum licensed dose).
- Mounjaro: 2.5mg starter → 5mg → 7.5mg → 10mg → 12.5mg → 15mg (the maximum licensed dose).
Your prescriber decides how quickly to move up doses and where to settle, based on how you respond and tolerate the medicine.
What the trials showed
In the OASIS 4 trial, adults on oral semaglutide 25mg lost on average 16.6% of their body weight over 64 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this.
In the SURMOUNT-1 trial, participants on the Mounjaro 15mg dose lost on average 22.5% of body weight over 72 weeks, alongside lifestyle support. Individual results vary; not everyone reaches this.
Because these came from different trials with different participants and durations, the numbers are not a like-for-like comparison. They tell you what each medicine achieved in its own study — not that one will outperform the other for you.
Side effects
Both medicines share the GLP-1 class side-effect profile. The most common effects (affecting more than 1 in 10 people) include nausea, diarrhoea, constipation, vomiting, decreased appetite and fatigue. These are often most noticeable early on and after dose increases, and tend to ease as your body adjusts — one reason for the slow titration.
Rare but serious effects can include severe allergic reaction, acute pancreatitis, severe hypoglycaemia, severe gastrointestinal disease and, with tirzepatide, worsening diabetic retinopathy. If you experience severe or persistent symptoms, seek medical advice promptly.
You can report any suspected side effect through the MHRA Yellow Card scheme at https://yellowcard.mhra.gov.uk/.
Who can be prescribed either treatment
Eligibility is the same across these treatments. You may be considered if you are aged 18 or over and have:
- a BMI of 30 or above (obesity), or
- a BMI of 27–30 with a weight-related condition such as type 2 diabetes, high blood pressure or sleep apnoea.
Neither is suitable if you are pregnant, planning pregnancy or breastfeeding; have type 1 diabetes; have a personal or family history of medullary thyroid carcinoma or MEN2; have a history of pancreatitis; have severe gastrointestinal disease; have an active eating disorder; have severe liver or kidney impairment; or are allergic to the active ingredient.
A treatment is prescribed only if clinically appropriate after a consultation — a prescription is never guaranteed.
Cost compared
The Wegovy Tablet starts from £115/month (1.5mg) rising to £190/month at the 25mg dose. Mounjaro starts from £160/month (2.5mg) rising to £295/month at 15mg. Your monthly cost depends on the dose you settle on, not just the starting price.
At The Weight Clinic the online consultation is free — you only pay if a treatment is prescribed and you choose to proceed. See the full range on our treatments page.
Which might suit you?
There is no universal answer. A daily tablet with strict timing suits people who prefer to avoid injections and can commit to an empty-stomach morning routine. A weekly injection suits people who prefer a single weekly action and no food-timing rules.
Mechanism, trial data, side-effect tolerance, cost and lifestyle all play a part — and only a prescriber can weigh these against your medical history. If you would like an assessment, start with our free online consultation, or read more about weight-loss injections and how our regulated service works.
This article is for information only and is not a substitute for personalised medical advice. Weight-loss medicines are prescription-only, are not suitable for everyone, and are prescribed only after a clinical consultation with a GPhC-registered prescriber. Individual results vary. Always speak to a UK-registered pharmacist or doctor before starting or changing any prescription medication.
