Wegovy or Mounjaro?
Both are prescription-only weekly injections for weight management. They work differently, start at different doses and come in different pens. Wegovy also comes as a tablet taken once a day. Here is a side-by-side view of the official information.
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Side by side
Pick a topic. Only facts from the official product information. Which medicine is right for you, if any, is a medical decision.
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| Mounjaro | Wegovy | |
|---|---|---|
| Active substance | Tirzepatide | Semaglutide |
| How it acts | On GIP and GLP-1 receptors | On GLP-1 receptors |
| Made by | Eli Lilly | Novo Nordisk |
| Approved for weight management | Adults with BMI ≥30, or ≥27 with a weight-related condition | Adults with BMI ≥30, or ≥27 with a weight-related condition; also adolescents from 12 with obesity and body weight over 60 kg |
| How it is taken | Injection once a week | Injection once a week, or a tablet once a day |
| Form marketed in Spain | KwikPen, 2.5 mg to 15 mg per dose (4 doses per pen) | FlexTouch pen, 0.25 mg to 2.4 mg; 7.2 mg single-use pen; tablets, 1.5 mg to 25 mg |
| Starting dose | 2.5 mg for 4 weeks | 0.25 mg for 4 weeks |
| Dose steps | +2.5 mg after at least 4 weeks, if needed | Every 4 weeks over 16 weeks |
| Maintenance doses | 5, 10 or 15 mg (maximum 15 mg) | 2.4 mg, or 7.2 mg after at least 4 weeks on 2.4 mg |
| Missed dose window | Up to 4 days | Up to 5 days |
| After first use, the pen keeps | 30 days | 6 weeks |
| Stop before a planned pregnancy | At least 1 month | At least 2 months |
| Breastfeeding | Could be considered (discuss with the doctor) | Should not be used |
Wegovy tablets have their own schedule. 1.5 mg once a day for 4 weeks, then a higher dose every 4 weeks, up to 25 mg from week 13. They are for adults only. The tablet is taken on an empty stomach after at least 8 hours without food, then you wait at least 30 minutes before eating, drinking or taking other medicines. The other Wegovy figures on this page are for the injection.
Based on the official EMA product information for Mounjaro and Wegovy and the Spanish medicines agency database, AEMPS CIMA. This page is general information, not medical advice: whether a medicine is appropriate for you is decided by a doctor after an assessment.
What they have in common
Prescription only
Both need a prescription after a medical assessment. A prescription is never guaranteed.
Diet and activity
Both are approved as an addition to a reduced-calorie diet and more physical activity.
Stomach side effects
Nausea, diarrhoea, vomiting and constipation are very common with both, mostly while the dose is being increased.
Pick a time that suits you.
Times are shown in Spain time. No membership and no subscription. Emergency? Call 112.
Questions people ask
112 for emergencies. English Doctor is not an emergency service.
Is Mounjaro stronger than Wegovy?
The official product information does not rank one above the other for an individual patient. They contain different active substances, work differently and have different dose schedules. A doctor decides which, if any, is appropriate for you.
Can I switch from Wegovy to Mounjaro, or the other way round?
Switching between medicines is a medical decision. Talk it through with a doctor, who will consider your history, current dose and how you have tolerated treatment.
Are both available in Spain?
Yes. According to AEMPS CIMA, Mounjaro is marketed as the KwikPen. Wegovy is marketed as the FlexTouch pen, the 7.2 mg single-use pen and tablets. All need a prescription.
Which one has fewer side effects?
Both list nausea, diarrhoea, vomiting, constipation and stomach pain as very common. The doctor will go through the side effects of each with you.