Can You Take Orlistat and Mounjaro Together?

Orlistat works in the gut by reducing the amount of dietary fat your body absorbs, while Mounjaro (tirzepatide) acts on GLP-1 and GIP receptors to influence appetite and blood sugar regulation. Because they act through entirely different pathways, there is no well-documented direct pharmacokinetic interaction between them — but that does not mean combining them is automatically straightforward or suitable for everyone.

A few practical considerations are commonly raised by people asking this question:

• Gastrointestinal effects may compound. Both medicines can cause digestive side effects — orlistat is well known for causing oily stools, urgency, and loose stools, particularly if fat intake is high, while Mounjaro commonly causes nausea, diarrhoea, and stomach discomfort, especially early in treatment or after a dose adjustment. Taking both at the same time could mean these effects are more noticeable.
• Absorption of other medicines. Orlistat is known to affect the absorption of some medications. Your prescriber or pharmacist is best placed to review your full medication list in light of this.
• Your prescriber decided your current treatment plan. Any addition or change — including adding orlistat — should go back through them, not be decided independently.

Questions about other combinations come up frequently too. If you are wondering about taking antibiotics alongside Mounjaro, or about using codeine while on Mounjaro, the same principle applies: always check with your prescriber or pharmacist before combining any medicines.

Some people also ask about metformin. Metformin is commonly prescribed for type 2 diabetes and is sometimes used alongside GLP-1 receptor agonists — but again, whether that combination is right for you depends on your individual circumstances and is a decision for your prescriber. Similarly, questions about topiramate alongside Mounjaro are worth raising with your doctor, as topiramate has its own interaction profile that requires clinical review.

It is also worth noting that taking Wegovy (semaglutide) and Mounjaro (tirzepatide) together is not appropriate — these are both GLP-1-based medicines and would not be prescribed simultaneously. For a factual comparison of the two, see our page on Wegovy and Mounjaro.

For a broader overview of Mounjaro and how it works, visit our Mounjaro information hub.

When you are managing multiple medicines, keeping a clear record of what you are taking and how your body is responding becomes genuinely useful — both for your own awareness and for conversations with your prescriber.

GLP Trackr's side-effect and symptom tracking feature is particularly helpful here. You can log digestive symptoms — nausea, urgency, loose stools, discomfort — on a daily basis, and over time the app surfaces patterns that can be hard to spot in the moment. If you start noticing that certain symptoms cluster around particular days or doses, that documented history is far more useful to bring to a prescriber appointment than trying to recall it from memory.

The app also lets you log each Mounjaro injection — dose strength, date, and time — so your full picture of treatment is in one place rather than scattered across notes and memory. If a symptom change coincides with a dose stage, you will have the data to discuss it clearly.

If you are experiencing side effects that feel severe, persistent, or worrying — from either medicine — contact your healthcare professional promptly. GLP Trackr helps you record what is happening so you can have an informed conversation; it is not a substitute for clinical advice, and it does not tell you whether a symptom is or is not serious. Any decision about your medication — including whether to continue, pause, or combine medicines — belongs with your prescriber.

Start logging your symptoms and injection history with a free 7-day trial — available now on the App Store and Google Play.