The most important combinations
- The pill: May work less well on tirzepatide – more in the contraception guide
- Insulin and sulfonylureas: Combined with GLP-1 medications, the risk of low blood sugar rises. The dose is often adjusted
- Blood thinners (e.g. Marcumar/phenprocoumon), thyroid hormones: Even small changes in absorption can have an effect – have your levels checked more closely
- Blood pressure medication and diuretics: Dehydration from vomiting or diarrhoea can lead to dizziness and kidney problems
- Appetite-suppressing medication (e.g. some ADHD drugs): The effects add up – the risk of eating far too little rises
Unapproved substances
For research peptides there is no prescribing information and no verified data on interactions. If you take them, you should still tell your doctor – only then can they correctly assess your symptoms. Medical confidentiality applies here too.
What to do in practice
- Keep an up-to-date list of all your medications and supplements
- Watch for new symptoms when starting and at every dose increase
- Ask your pharmacy for an interaction check – in Germany this is free of charge
When to see a doctor
- Trembling, sweating, sudden intense hunger or confusion (low blood sugar) on diabetes medication
- Dizziness or fainting on blood pressure medication
- You take blood thinners or thyroid hormones and are starting a GLP-1 medication
In an emergency: 112.
FAQ
Which medications don’t go with Mounjaro?
An outright ban is rare, but there are important interactions: the pill, insulin and sulfonylureas, and drugs with a narrow dosing range such as blood thinners and thyroid hormones.
Can I take ADHD medication and the weight-loss injection together?
That has to be decided by a doctor. Both suppress appetite – the risk of eating too little goes up.
Do I have to tell my doctor that I take research peptides?
Yes, that makes sense. Only then can they correctly assess your symptoms. Medical confidentiality applies.
Sources
This article does not replace medical advice. It gives no dosing recommendations. As of September 2026.