Medication vs Medication
Mounjaro vs Orlistat
A practical UK comparison focused on what is genuinely different — not which brand has the loudest marketing.
Mounjaro
Up to ~20%+ mean loss in obesity trials; direct head-to-head 20.2% at 72 weeks vs 13.7% semaglutide 1.7/2.4 mg in SURMOUNT-5
Orlistat
Typically produces more modest average loss than GLP-1/GIP medicines; individual response varies
Side-by-side
| Mounjaro | Orlistat | |
|---|---|---|
| Active ingredient | tirzepatide | orlistat |
| Form | Weekly injection | Capsule with meals |
| Frequency | Once weekly | Up to three times daily with fat-containing meals |
| Licence | UK weight management licence | UK weight management licence |
| NHS context | NICE-recommended; NHS access is phased / pathway-dependent | Long-established NHS option; prescribing criteria and local practice apply |
| Evidence | Very strong | Very mature |
| Weight-loss evidence | Up to ~20%+ mean loss in obesity trials; direct head-to-head 20.2% at 72 weeks vs 13.7% semaglutide 1.7/2.4 mg in SURMOUNT-5 | Typically produces more modest average loss than GLP-1/GIP medicines; individual response varies |
| Maintenance | Long-term treatment may be needed; stopping can be followed by regain | Can be continued where effective/tolerated; diet composition affects tolerability |
| GI considerations | Common GI effects, especially during escalation | GI effects are closely related to dietary fat intake |
Reasons to discuss Mounjaro
- Highest head-to-head mean weight loss among the established injectable options in SURMOUNT-5
- Weekly dosing
- Strong appetite / food-noise effect for many users
- Weight-management and maintenance licence
Trade-offs
- Injection
- GI side effects can be limiting
- Access and NHS rollout are not the same as NICE eligibility
- Ongoing treatment cost/maintenance matters if private
Reasons to discuss Orlistat
- Needle-free
- Generic and established
- Different mechanism from incretin medicines
- Usually lower drug cost than branded incretin therapy
Trade-offs
- Lower average efficacy
- Oily stools/urgency and other GI effects can be disruptive
- Must be taken around fat-containing meals
- Fat-soluble vitamin considerations
Which is stronger for weight loss?
Mounjaro is rated 10/10 and Orlistat 3/10 in our comparison framework. That rating summarises the obesity evidence available for the licensed formulation; it is not a prediction of your result.
Which is easier to live with?
Mounjaro: Once weekly. Orlistat: Up to three times daily with fat-containing meals. For some people a weekly injection is easier than a daily tablet; for others avoiding a needle is decisive.
NHS vs private reality
NICE-recommended; NHS access is phased / pathway-dependent. Long-established NHS option; prescribing criteria and local practice apply. NICE criteria and NHS availability are related but not identical, so check the current pathway rather than assuming a clinically eligible medicine is immediately available through a GP.
Maintenance matters
Long-term treatment may be needed; stopping can be followed by regain. Can be continued where effective/tolerated; diet composition affects tolerability. A treatment comparison that ends at the point of weight loss is incomplete.
Questions to ask a prescriber
- Which option is actually licensed and clinically appropriate for my health history?
- How do the expected benefits compare for someone with my diabetes/cardiovascular history?
- What side effects should make me contact you?
- What will monitoring involve?
- What is the plan if I cannot tolerate the maintenance dose?
- What happens if I stop?
Sources
Continue exploring