Switching From Mounjaro to Foundayo

The introduction of Foundayo as an oral GLP-1 medication in 2026 marked another important step forward in how people can access a medicated weight loss programme when a healthy diet and regular exercise alone aren’t having the desired effects. It became just the second treatment of its type licensed to combat obesity, behind the Wegovy Pill. Before these two breakthrough treatments, weight loss pills didn’t really offer a viable alternative to injections in terms of how effective they could be. 

Foundayo is manufactured by Eli Lilly, the same company behind Mounjaro injections. Mounjaro is regarded as one of the most effective treatments available, potentially leading to a 22.5% weight loss after 72 weeks. As you’d expect, the launch of this new product has prompted comparisons between the two medications, with some people wondering if they would be better off changing from injections to tablets.

In this article, we’ll explore switching from Mounjaro to Foundayo, outline the process, explain why you might want to do it, and describe what your weight-loss journey could look like on the new medication. Let’s begin. 

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Can You Change From Mounjaro to Foundayo?

You can switch from Mounjaro injections to Foundayo pills, but only under the supervision of a licensed clinician. People change their GLP-1 medication for a variety of reasons; for example, to:

• Increase weight loss
• Improve blood sugar control
• Reduce side effects
• Enhance cardiovascular benefits
• Improve convenience and adherence to the dosing schedule
• Manage the cost-effectiveness of treatment

If you want to swap one GLP-1 medication for another, it’s important to weigh your reasons for the change and research alternatives carefully. Speak to a clinician about your motivation to switch, so they can help you ‌determine if Foundayo is the most suitable choice for your needs.

Who Can Switch From Mounjaro to Foundayo?

You can swap Mounjaro for Foundayo if a prescribing clinician deems the change appropriate for your personal needs. GLP-1 medications vary in their strength and usage, and switching without proper medical guidance could increase your risk of side effects or make your treatment less effective.

You must also meet the prescription criteria for Foundayo. Doctors usually prescribe Foundayo to people with a BMI of 30 kg/m² or to those whose BMI falls between 27 kg/m² and 30 kg/m² and who have at least one weight-related health condition. Examples of weight-related health problems include:

• Prediabetes
• Type 2 diabetes
• High blood pressure
• High cholesterol
• Obstructive sleep apnoea
• Impaired heart function
• Medical history of heart attack, stroke, or other cardiovascular events

Always seek the advice of a healthcare professional before changing your GLP-1 medication. If Foundayo is a more suitable option for you than Mounjaro, they will create a treatment plan that allows you to safely swap one medication for the other.

Why Consider Stopping Mounjaro for Foundayo

Different GLP-1 medications have different administration methods, benefits, and side effects. People may consider stopping Mounjaro in favour of Foundayo because they prefer taking pills to self-injecting, to manage gastrointestinal side effects, or to maintain their weight loss.

Preference for Pills

A key reason to swap Mounjaro for Foundayo may be a preference for pills over injections. Foundayo is a once-daily oral medication you can take at any time of day. Many people find this more convenient than Mounjaro, which is a weekly injection that requires users to prepare and prime the injection pen before each dose. This can make Foundayo a more attractive choice for people with busy schedules or who travel frequently.

Foundayo may also be the preferable option for people with a fear of needles or mobility issues that make self-injection challenging. Taking an oral medication also eliminates the risk of injection site reactions such as rashes, pain, redness, and swelling.

Managing Gastrointestinal Side Effects

All GLP-1 medications have the potential to cause gastrointestinal side effects such as nausea, vomiting, diarrhoea, and constipation. These side effects are dose-dependent and typically spike at the start of treatment and around dose increases. Though most are mild to moderate and improve as your body adjusts to the medication, their intensity can vary between individuals. Therefore, people with severe gastrointestinal symptoms on Mounjaro may try Foundayo as an attempt to mitigate these side effects.

Maintaining Weight Loss

Mounjaro is a highly effective weight loss medication, but its effects don’t continue indefinitely. Clinical trials have found that most tirzepatide users reach a weight loss plateau, where they stop losing weight, by week 72 of treatment. Switching to Foundayo won’t necessarily restart weight loss, but it may help people maintain their lower weight.

Studies show that people often regain a large proportion of weight after they stop Mounjaro injections. However, people who used Foundayo after stopping Mounjaro managed to keep around three-quarters of the weight off. Therefore, you may want to try Foundayo to maintain your Mounjaro weight loss after stopping the injections.

Foundayo (Orforglipron)

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• Oral GLP-1 tablet
• Manufactured by Eli Lilly
• Clinical trials show weight loss of around 12.4% after 72 weeks

• Discreet delivery next working day
• Online prescription - No doctor visit

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What Will Your Starting Dose of Foundayo Be?

Because Foundayo and Mounjaro contain different active ingredients (orforglipron and tirzepatide, respectively), the process of switching from Mounjaro to Foundayo isn’t as straightforward as swapping one dose for another. There is actually a designated switching protocol in place to help you make the change as safely as possible.

Your starting dose of Foundayo will depend on several factors, such as your current Mounjaro dose and how well you are responding to treatment (for example, whether you're tolerating side effects well and achieving acceptable weight loss). The table below illustrates what your first dose of orforglipron could be at Prescription Doctor, though this is not a guarantee. 

It’s important to note that the designated switching protocol does not allow for a starting Foundayo dose higher than 9 mg. This means that even if you’re well-established at the highest strengths of Mounjaro, it’s not possible to begin on the 14.5 mg or 17.2 mg tablets.

Ultimately, your starting Foundayo dose will depend on your unique circumstances. Our experienced clinicians will review your treatment history to determine the safest and most appropriate strength for you. 

How Do the Side Effects Compare?

Both Mounjaro and Foundayo frequently cause gastrointestinal side effects, including nausea, vomiting, and diarrhoea. These symptoms are most common at the start of treatment and during dose escalation, but usually decrease over time. The table below outlines the most common adverse reactions associated with tirzepatide and orforglipron. 

Both medications can also cause hypoglycemia (very low blood sugar), especially when used alongside other anti-diabetic medications. Both medications can also cause more serious medical conditions, such as acute pancreatitis or kidney injury (usually as a consequence of dehydration brought about by diarrhoea and vomiting). Though they have similar safety profiles, one meta-analysis reported that Foundayo has a higher nausea risk than Mounjaro.

If you’d like more information about the side effects of Foundayo, check out our dedicated article. You can also find an in-depth look at Mounjaro’s side effects on our website. 

How to Switch From Mounjaro to Foundayo

Tirzepatide, the active ingredient in Mounjaro, has a half-life of around 5 days, meaning it can take several weeks for the medication to fully leave your system.

For this reason, your prescriber may recommend a washout period: a planned pause between taking Mounjaro and starting Foundayo. This may be necessary to avoid exposing your body to two different GLP-1 medications at once, which could increase your risk of hypoglycaemia and other side effects.

UK health sources don’t specify a defined washout period for Mounjaro, as the number of days you should wait between medications depends on several factors. These may include your reasons for switching medications, your medical history, and the strength of your Mounjaro dose. Therefore, you should always consult a licensed clinician for advice before attempting to swap one GLP-1 medication for another.

Foundayo (Orforglipron)

Rated 0 out of 5 based on 0 reviews

Rated 0 out of 5 based on 0 reviews

• Oral GLP-1 tablet
• Manufactured by Eli Lilly
• Clinical trials show weight loss of around 12.4% after 72 weeks

• Discreet delivery next working day
• Online prescription - No doctor visit

Prices from £109.00 Review More Prices

Start Order More Info

Get Started

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How Will Switching From Mounjaro to Foundayo Affect Weight Loss Progress?

How the change from Mounjaro to Foundayo may affect weight loss progress will vary between individuals. Tirzepatide is a dual-receptor agonist, meaning it mimics two gut hormones simultaneously (GLP-1 and GIP), whereas orforglipron only targets the GLP-1 pathway. This often translates to greater weight loss efficacy, with people on Mounjaro typically losing more weight than those taking Foundayo. Therefore, your rate of weight loss may slow down if you switch from Mounjaro to Foundayo.

However, Foundayo can also promote significant weight loss, with one clinical study finding that participants lost an average of 12.4% of their body weight after 72 weeks of treatment.

Some people consider changing from Mounjaro to Foundayo when they reach a weight loss plateau. The goal here is often weight maintenance rather than further weight loss. It is very common for people to regain weight when they stop using GLP-1 injections, but research suggests that Foundayo may help people maintain a lower weight after discontinuing Mounjaro.

What to Expect After Switching From Mounjaro to Foundayo?

Mounjaro and Foundayo have similar effects on the body, but they are not the same drug. Therefore, switching from one to the other requires a clinician-led plan to safely discontinue injections and begin a Foundayo dosing schedule. Here, we’ll discuss what you can expect in the first 3 and 6 months after switching from Mounjaro to Foundayo.

First 3 Months

The first 3 months of switching from Mounjaro to Foundayo are likely to involve a transition and titration phase. Your prescribing clinician will set a washout period during which you won’t take either medication. After this, you will begin the Foundayo treatment plan.

As Foundayo is a different medication than Mounjaro, your body will need time to adjust even if you were taking a high tirzepatide dose. The official starting dose for Foundayo is 0.8mg, increasing to 2.5 mg, 5.5 mg, 9 mg, 14.5 mg, and finally 17.2 mg. You must stay on each dose for at least 30 days, titrating up only to improve weight-loss results if you tolerate the medication well.

It may take a few weeks to feel the effects of Foundayo, with one study reporting appetite suppression by week 4 of treatment. By week 12, participants had reduced their food intake and begun losing weight.

First 6 Months

By month 6, you may have increased your Foundayo dose to the maximum 17.2 mg per day. As the effects of the medication are dose-dependent, your appetite and food intake may have continued to decline throughout treatment. However, your rate of weight loss in the first 6 months will heavily depend on your starting weight, your Mounjaro dosage, and whether you reached a weight loss plateau on Mounjaro.

You may continue losing weight at a steady rate, or your weight loss may slow on Foundayo. If you had stopped losing weight on Mounjaro, your weight may remain stable once you switch to Foundayo.

Can You Switch Back to Mounjaro From Foundayo?

You can switch back to Mounjaro from Foundayo, and may choose to do so if you are dissatisfied with your rate of weight loss on Foundayo, or if you experience uncomfortable side effects. Always discuss your concerns with a licensed clinician before changing your treatment plan, so they can assess your needs and recommend the most appropriate medication. If you decide to go back on Mounjaro, your clinician will also formulate a treatment plan that allows you to do so safely.

Specialist Support Throughout Your Journey

If you’re considering switching from Mounjaro to Foundayo, Prescription Doctor is here to help. Since 2013, we’ve supported countless individuals with their weight loss journeys, and we’re perfectly placed to do the same for you.

Our experienced clinicians are on hand to discuss the process with you, including your reasons for switching, and to assess whether Foundayo would suit your individual circumstances and routine. This helps you make a more informed decision about your next course of action. Once you're on your new routine, they will also check in regularly to monitor progress and ensure everything is working as planned.

We’re with you at every stage of your weight loss journey, offering advice and support that’s tailored for you. We even have a library of essential information about Foundayo on our website, including an overview of the medication and comparison guides between Wegovy injections and Wegovy pills.

Ready to begin? Start your consultation with Prescription Doctor today.

Authored By

Kate Latham

Medical Content Writer

Kate has been a scientific content writer since 2017. With a BSc in Biology and a background in cancer research, she is adept at identifying the latest findings in medical research and utilising these

Published on: 29/09/2026

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 29/09/2026