Jump to: How we assess compatibility | What the tool doesn’t do | Common combinations | Comparison table | What to discuss with your prescriber | FAQs
If you’re considering a weight loss medication like Mounjaro, Wegovy, or Foundayo, one of the first questions you’ll probably have is whether it’s safe to take alongside your existing health conditions or medications.
Many people taking GLP-1 medications also live with conditions like type 2 diabetes, high blood pressure, or thyroid problems, or take regular prescriptions like metformin, statins, or antidepressants.
Our free compatibility checker covers Mounjaro, the Wegovy injection, the Wegovy pill, and Foundayo. Select your medication and conditions to see a quick summary of general compatibility, based on current UK prescribing guidelines.
Important safety information: This tool provides general compatibility information based on UK prescribing guidelines. It doesn’t assess your individual eligibility for treatment. Only a prescriber can determine whether a medication is suitable for you during a clinical consultation. Never stop or change any medication without speaking to your doctor first.
How we assess compatibility
The tool uses a traffic light system to give you a quick overview of each combination:
- Green (generally compatible): no significant concerns based on current guidelines. The medication can typically be used alongside your condition or other medications
- Amber (compatible with caution): the combination is generally possible, but may need extra monitoring, dose adjustments, or specialist input
- Red (significant concern): there’s a known contraindication or serious clinical concern. Your prescriber will need to assess this carefully
Each result includes a short summary, key considerations, and a link to a longer guide that covers the combination in more detail.
The information is drawn from the Summary of Product Characteristics (SPC) for each medication, the British National Formulary (BNF), NICE guidelines, and published clinical trial data1,2.
What the tool doesn’t do
This tool isn’t an eligibility checker. In the UK, eligibility for prescription weight loss medications is assessed by a prescriber during a clinical consultation3.
The tool can’t account for your full medical history, the severity of your condition, or how your individual body responds to medication. It provides general guidance to help you prepare for a conversation with your doctor.
Think of it as a starting point, not a final answer on your next course of treatment.
Common combinations people check
Based on the conditions most commonly searched alongside GLP-1 medications, here are some of the combinations people ask about most frequently.
Mounjaro or Wegovy with type 2 diabetes
Both medications are compatible with type 2 diabetes. Mounjaro is licensed for type 2 diabetes in the UK, and semaglutide (the drug in Wegovy) is also used at lower doses as Ozempic for blood sugar management1.
Foundayo (orforglipron) is licensed in the UK for both type 2 diabetes and weight management6.
If you’re taking insulin or sulfonylureas, your prescriber may need to reduce your doses to avoid low blood sugar as the GLP-1 takes effect.
Mounjaro or Wegovy with high blood pressure
Both medications are generally compatible with blood pressure treatment. Weight loss itself often improves blood pressure, so your prescriber may review your antihypertensive doses as you lose weight.
Mounjaro or Wegovy with metformin
This is one of the most common combinations in clinical practice. Both Mounjaro and Wegovy can be taken alongside metformin, and many clinical trials studied them together4.
The main thing to be aware of is that GI side effects (nausea, diarrhoea) can overlap between the two, so your prescriber may suggest a slower titration schedule.
Mounjaro or Foundayo with oral contraceptives
This combination needs caution. Mounjaro slows gastric emptying, which may reduce the absorption of oral contraceptives.
The SPC advises switching to a non-oral contraceptive method or adding a barrier method (such as condoms) for four weeks after starting Mounjaro and after each dose increase1.
Foundayo can also reduce how well the contraceptive pill works. Its SPC advises switching to a non-oral method or adding a barrier method for 30 days after starting Foundayo and for 30 days after each dose increase6.
Foundayo has six dose steps, so someone who moves through every step will need extra precautions for six separate 30-day periods.
Non-oral contraceptives like the implant, IUD, or injection aren’t affected.
Mounjaro or Wegovy with antidepressants
SSRIs like sertraline and citalopram can generally be taken alongside both Mounjaro and Wegovy.
There are no significant pharmacological interactions between GLP-1 medications and most antidepressants.
It’s worth monitoring your mood during weight loss, as significant changes in your body can affect how you feel emotionally.
Mounjaro or Wegovy with hypothyroidism
Both medications can generally be used alongside levothyroxine for hypothyroidism.
However, GLP-1 medications slow gastric emptying, which may delay the absorption of levothyroxine1,2.
Your prescriber may recommend taking levothyroxine at least 30 minutes before food and monitoring your thyroid function more frequently when starting treatment.
If your TSH levels change after starting a GLP-1, your levothyroxine dose may need adjusting.
The Wegovy pill also has to be taken on an empty stomach with a wait before food, so it can’t be taken at the same time as levothyroxine. Your prescriber will help you take the two at different times of day.
Foundayo has no fasting window and can be taken at any time of day, with or without food. You can keep taking levothyroxine first thing on an empty stomach and take Foundayo later in the day6.
Mounjaro or Wegovy with statins
Statins such as atorvastatin and rosuvastatin can be taken alongside Mounjaro and Wegovy. Neither tirzepatide nor semaglutide has a significant interaction with statins1,2.
Foundayo can be taken with most statins, but it increases the amount of active simvastatin in the blood by up to 2.5 times. The Foundayo SPC advises halving the simvastatin dose, and caution with rosuvastatin doses above 20 mg6.
Weight loss itself often improves cholesterol levels. Your prescriber may review your statin dose as you lose weight, particularly if your LDL cholesterol drops significantly.
Mounjaro or Wegovy with warfarin
Both medications can be used alongside warfarin, but this combination needs careful monitoring. GLP-1 medications slow gastric emptying, which can affect how warfarin is absorbed1,2.
Weight loss can also change how your body processes warfarin, which may shift your INR (a measure of how quickly your blood clots). More frequent INR checks are recommended during the early months of treatment.
For a detailed guide, see our Wegovy and warfarin article.
Mounjaro or Wegovy with PCOS
Both medications are compatible with polycystic ovary syndrome. Weight loss can improve many PCOS symptoms, including insulin resistance, irregular periods, and fertility1,2.
If you’re taking metformin for PCOS, both GLP-1 medications can be used alongside it, though GI side effects may overlap.
If you’re trying to conceive, both Mounjaro and Wegovy should be stopped at least two months before conception. Speak to your prescriber about timing1,2.
Foundayo leaves the body more quickly, so its SPC advises stopping it at least 3 weeks before a planned pregnancy6.
Mounjaro or Wegovy with kidney disease
Both medications can be used in mild to moderate kidney disease without dose adjustment1,2.
In severe kidney disease (eGFR below 15), clinical experience is limited. The SPCs don’t recommend Mounjaro or Wegovy in this group due to insufficient data, not a known safety concern.
The Foundayo SPC says no dose adjustment is needed at any level of kidney function, including end-stage kidney disease6.
GI side effects like nausea and vomiting can cause dehydration, which may worsen kidney function. Your prescriber will likely monitor your kidney function more closely during dose titration1,2.
Mounjaro vs Wegovy vs Foundayo compatibility comparison
The table below summarises how Mounjaro, Wegovy, and Foundayo compare across the most commonly checked conditions. All three are compatible with most conditions. The main differences are with oral contraceptives, levothyroxine, statins, and severe kidney disease1,2,6.
| Condition or medication |
Mounjaro (tirzepatide) |
Wegovy injection and pill (semaglutide) |
Foundayo (orforglipron) |
| Type 2 diabetes |
🟢 Compatible. Also licensed for T2D |
🟢 Compatible. Semaglutide also used as Ozempic for T2D |
🟢 Compatible. Also licensed for T2D |
| High blood pressure |
🟢 Compatible. May improve with weight loss |
🟢 Compatible. May improve with weight loss |
🟢 Compatible. May improve with weight loss |
| Metformin |
🟢 Compatible. GI side effects may overlap |
🟢 Compatible. GI side effects may overlap |
🟢 Compatible. GI side effects may overlap |
| Oral contraceptives |
🟡 Caution. May reduce absorption; barrier method advised for 4 weeks after each dose increase |
🟢 Compatible. No known absorption effect |
🟡 Caution. Non-oral or barrier method for 30 days after starting and after each dose increase |
| Antidepressants (SSRIs) |
🟢 Compatible. No significant interactions |
🟢 Compatible. No significant interactions |
🟢 Compatible. No significant interactions |
| Hypothyroidism (levothyroxine) |
🟡 Caution. May delay levothyroxine absorption |
🟡 Caution. May delay levothyroxine absorption. Take the pill at a different time from levothyroxine |
🟢 Compatible. No fasting window, so no timing clash with levothyroxine |
| Statins |
🟢 Compatible. No significant interactions |
🟢 Compatible. No significant interactions |
🟡 Caution. Halve the simvastatin dose; caution with rosuvastatin above 20 mg |
| Warfarin |
🟡 Caution. Monitor INR more frequently |
🟡 Caution. Monitor INR more frequently |
🟡 Caution. Monitor INR more frequently |
| PCOS |
🟢 Compatible. Weight loss may improve symptoms |
🟢 Compatible. Weight loss may improve symptoms |
🟢 Compatible. Weight loss may improve symptoms |
| Kidney disease (mild to moderate) |
🟢 Compatible. No dose adjustment needed |
🟢 Compatible. No dose adjustment needed |
🟢 Compatible. No dose adjustment needed |
| Kidney disease (severe, eGFR <15) |
🔴 Insufficient data. Not recommended |
🔴 Insufficient data. Not recommended |
🟡 Caution. No dose adjustment, but dehydration from side effects can harm the kidneys |
This table covers the most commonly searched combinations. For conditions not listed here, use the compatibility checker above or check the BNF directly.
What to discuss with your prescriber
If you’re considering starting a GLP-1 medication, it can be helpful to go into your appointment with a clear picture of your current health. Your prescriber will want to know:
- All medications you’re currently taking, including over-the-counter medicines and supplements
- Any health conditions you have, even if they seem unrelated to weight
- Whether you’re pregnant, breastfeeding, or planning to conceive
- Any previous reactions to injections or medications
The ‘Save as PDF’ feature in the compatibility checker lets you download your results to bring to your appointment. This can help structure the conversation and make sure nothing gets missed.
Frequently asked questions
Is the compatibility checker free?
Yes. The tool is completely free and doesn’t require an account or sign-up.
Does this tool tell me if I’m eligible for Mounjaro, Wegovy, or Foundayo?
No. It checks general compatibility between a medication and your health conditions. It doesn’t assess your individual eligibility for treatment.
Only a prescriber can determine whether a medication is suitable for you during a clinical consultation3.
What does ‘compatible with caution’ mean?
An amber result means the medication can generally be used alongside your condition, but extra monitoring, dose adjustments, or specialist input may be needed.
Your prescriber will assess the specifics of your situation.
Can I check multiple conditions at once?
Yes. You can select as many conditions or medications as apply to you. The tool shows a separate result card for each combination, sorted by severity so you see the most important information first.
Where does the compatibility information come from?
The information is based on the Summary of Product Characteristics (SPC) for each medication, the British National Formulary (BNF), NICE guidelines, and published clinical trial data1,2.
Each result links to a detailed Second Nature guide where available.
My condition isn’t listed. What should I do?
The tool currently covers 89 conditions and medications. If yours isn’t listed, you can check the BNF for prescribing information or speak to your prescriber or pharmacist directly.
We’re regularly adding new combinations as we publish more guides.
Can I save my results?
Yes. There’s a ‘Save as PDF’ button on the results screen. This is useful if you want to take your results to a GP appointment or share them with your prescriber.
What’s the difference between Mounjaro, Wegovy, and Foundayo?
Mounjaro contains the drug tirzepatide, a dual GLP-1 and GIP receptor agonist. Wegovy contains semaglutide, a GLP-1 receptor agonist, and comes as an injection once a week or a pill once a day1,2.
Foundayo contains orforglipron, a GLP-1 receptor agonist taken as a tablet once a day, with or without food. All three are licensed in the UK for weight management6.
The compatibility checker lets you switch between Mounjaro, the Wegovy injection, the Wegovy pill, and Foundayo to compare results for the same conditions. For a detailed comparison, see our Wegovy vs Mounjaro guide.
Should I stop my current medication before starting a GLP-1?
Never stop or change any medication without speaking to your prescriber first. In many cases, existing medications can be taken alongside a GLP-1, though doses may need adjusting.
Is this tool a substitute for medical advice?
No. The tool provides general information based on current UK prescribing guidelines. It doesn’t replace a clinical consultation. Always discuss your full medical history with your prescriber before starting any new medication.
Our condition guides cover Mounjaro with type 2 diabetes, high blood pressure, metformin, and PCOS.
Take home message
Most common health conditions and medications are compatible with GLP-1 weight loss treatments, though some combinations need extra monitoring or clinical oversight.
This tool gives you a quick overview based on current UK prescribing guidelines, so you can go into a conversation with your prescriber better informed.
If you’re considering starting a GLP-1 medication and want structured support alongside it, Second Nature’s programme combines clinician-led prescribing with dietitian support and a behaviour-change programme built on published 12-month outcomes.
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
