Orforglipron Vs Mounjaro For Weight Loss: What’s The Difference And Which Is Right For You?

Now that there are prescription weight loss treatments available to help manage obesity, new GLP-1 medicines (glucagon-like peptide-1 receptor agonists) are emerging all the time thanks to new research and clinical developments. That's good news for those who need help to lose weight, but it can make it difficult to know which treatment is the best option.

Two of the most talked about are orforglipron, an oral weight loss medication, and Mounjaro, an injectable treatment. In this guide, our experts will weigh up the key differences of orforglipron vs Mounjaro to help you understand how they compare, and which is better suited to your health goals.

Article Summary:

• Orforglipron and Mounjaro are two prescription weight loss medications created by the global pharmaceutical company Eli Lilly. They support weight loss by helping to increase fullness, regulate blood sugar levels, slow digestion and improve appetite regulation.
• Mounjaro contains the active ingredient tirzepatide, a dual GIP receptor and GLP-1 receptor agonist, and is taken as a weekly injection. Orforglipron is the active ingredient in Foundayo™, an oral GLP-1 receptor agonist that's taken as a daily pill.
• The main differences between the two weight loss treatments are how they’re taken, how they work, how effective they are, and their side effects.

Why Eli Lilly created orforglipron and Mounjaro

Eli Lilly is an American pharmaceutical company that’s known for creating treatments for type 2 diabetes, weight loss medications and other health products.

The company launched Mounjaro for weight loss in 2023, with availability starting from February 2024. It then developed orforglipron (under the brand name Foundayo), which was approved by the FDA in April 2026. Mounjaro is an injectable treatment, while Foundayo is an oral medication.

Though they're made by the same company, orforglipron is not 'oral Mounjaro', which is a common misconception. While Mounjaro contains that active ingredient tirzepatide, a dual GIP and GLP-1 receptor agonist, orforglipron is a different ingredient and is a GLP-1 receptor agonist only. They work in different ways, and produce different weight loss results.

Offering both delivery methods gives patients the choice of an oral or injectable medication, and may make weight loss treatments more accessible to those who need them.

What is orforglipron?

Orforglipron (pronounced or-FOR-gli-pron) is an oral weight loss medication launching in the UK in 2026. It’s marketed under the brand name Foundayo, but orforglipron is the name of the active ingredient.

It’s a glucagon-like peptide-1 receptor agonist, which means it mimics a natural hormone in your gut to help you to lose weight. It’s in the same class of medications as other weight loss treatments like Wegovy (semaglutide) and Mounjaro (tirzepatide). [1]

However, while these other treatments are peptide-based, orforglipron is a smaller, synthetic, non-peptide molecule. This is important because it means that orforglipron can resist being broken down by the digestive system when swallowed, making it possible to take it in an oral tablet form. [2]

Who it’s for: Orforglipron may be prescribed for adults with a body mass index (BMI) of 30 or higher. It may also be prescribed for those with a BMI of 25 or higher if you also have a weight-related health condition such as type 2 diabetes, high blood pressure, cardiovascular disease or high cholesterol. This is considered ‘off-label’ prescribing, meaning it’s not the officially approved usage but it is safe and common practice. [3]

What is Mounjaro (tirzepatide)?

Mounjaro is the brand name for an injectable weight loss medication. It contains the active ingredient tirzepatide, which was initially developed to treat type 2 diabetes but later approved to treat obesity. [4]

Tirzepatide is a dual GIP and GLP-1 receptor agonist, which means it mimics two natural gut hormones to support weight loss. It’s made from peptides (protein-like building blocks), which is why it’s given by an injection rather than an oral tablet. Peptide drugs can be broken down by the stomach and may not be as effective when taken orally. [4]

Who it’s for: Tirzepatide can be prescribed for adults with a BMI of 30 or higher, or a BMI of 27 or higher if you also have a weight-related health condition, such as high blood pressure, type 2 diabetes, cardiovascular disease or high cholesterol levels. [5]

Orforglipron vs Mounjaro: Comparing the key differences

So, which weight loss medication is right for you? Here we’ll break down the main differences between Foundayo and Mounjaro to help you compare their health benefits, side effects and results.

How you take and store your treatment

The most obvious difference between orforglipron and Mounjaro is how you take the medication and its dosing frequency.

Mounjaro comes in a pre-filled injection pen, and is injected once a week into the back of your upper arm, your thigh or your stomach. You’ll use a fresh needle for each dose, with each pen containing enough for four doses. Your injection should be taken at around the same time each week, at a time that suits your schedule. Mounjaro should also be stored in the fridge to keep the medication stable. [6]

Orforglipron (Foundayo) is an oral medication, designed to be taken once daily with water. It can be taken with or without food, so there’s no fasting required like there is with oral semaglutide, another oral weight loss medication (sold under the brand name Wegovy). Unlike Mounjaro, orforglipron doesn’t have to be refrigerated and can be stored at room temperature. [7]

Both treatments are usually prescribed at the lowest dose to start with. Your healthcare provider will then gradually increase your dose each month, if it’s appropriate and you’re tolerating the medication well (a process known as your titration schedule).

How they work in the body

They may be taken differently and have very different ingredients, but both orforglipron and Mounjaro work in similar ways.

They both help to support weight loss by:

• Reducing hunger by mimicking the hormone that tells your brain you're full
• Slowing stomach emptying to help you stay full between meals
• Regulating blood sugar levels to help reduce food cravings
• Managing appetite by silencing 'food noise', so that you think about food less often [2, 8]

Beyond weight loss, both treatments may also bring broader benefits for your cardiovascular and metabolic health, including better blood sugar control and improved blood pressure. However, because tirzepatide also acts on the GIP receptors in your body, Mounjaro may produce stronger effects in reducing your body weight. [4]

Efficacy and clinical data comparison

On that note, it’s important to know what results you can expect. This is another key factor to bear in mind when choosing orforglipron vs Mounjaro.

In clinical trials, users taking the highest dose of tirzepatide lost an average of 22.5% of their body weight over 72 weeks (1 year, 5 months). [10]

Meanwhile in clinical trials of orforglipron, users taking the highest dose lost an average of 12.4% of their body weight over 72 weeks. [11]

These results suggest that the injectable treatment, Mounjaro, is likely to produce more significant weight loss than the oral medication. However, this is based on different trials in different people, so they can't be compared directly.

Safety and side effects

When it comes to side effects, both medications come with a similar list. The most common are gastrointestinal, such as nausea, vomiting, diarrhoea, constipation, and indigestion.

For Mounjaro users, less common side effects include allergic reactions, dizziness, stomach pain, bloating, gas, fatigue, hair loss, and increased heart rate. [12]

For Foundayo users, other side effects include stomach (abdominal) pain, headache, swollen belly, fatigue, belching, heartburn, gas, and hair loss. [11]

Cost

When choosing between GLP-1 medicines, you’ll want to consider cost as well. This will vary based on your dose and healthcare provider, but in general, it’s likely that injectable treatments like Mounjaro will be more expensive than orforglipron.

Choosing the right treatment for your lifestyle

Deciding which weight loss treatment is right for you doesn’t only come down to the medical information, like how it works and what results it’s proven to deliver. The most important factor is how well it fits with your lifestyle, because the best treatment for you is the one you can take conveniently and consistently, without disrupting your routine too much.

With that in mind, there are a few things to consider when choosing your preferred medication.

Convenience for travel

Do you travel a lot for work, or go away often? You can take your medication with you, but you’ll need to make sure you have enough for the duration of your trip and that you stick to your dosing schedule. The oral option, orforglipron, may be easier to travel with.

Fitting it into your routine

How chaotic is your routine? Do you take other medications first thing? If the morning rush is a struggle, you might find a weekly treatment suits you better than a daily pill.

Fear of needles vs finding pills hard to swallow

This may be the most simple way to choose your treatment, but it’s just as important. If you have a fear of needles, or don’t feel comfortable injecting yourself weekly, then the oral medication will be the best fit for you. On the other hand if you’re forgetful when it comes to taking daily medications or struggle to swallow pills, you’ll be better suited to the injectable Mounjaro option.

The final verdict: Orforglipron vs Mounjaro

There’s no right answer here. Think about which format feels best for you, what results you’re looking for and how easily it’ll fit into your routine. And don’t forget, both medications need to be taken alongside a calorie-controlled diet and increased physical activity to achieve lasting weight management. [2, 9]

Weighing up a daily pill against a weekly injection? The right choice depends on your individual needs and preferences. At MedExpress, we offer online consultations with regular clinical check-ins, and a range of weight loss treatments including Mounjaro Pen, Wegovy Pen, Wegovy Pill and Foundayo (coming soon) and our team can help you find the right treatment for you.

References

1. Wharton S, Blevins T, Connery L, Rosenstock J, Raha S, Liu R, et al. Daily Oral GLP-1 Receptor Agonist Orforglipron for Adults with Obesity. The New England Journal of Medicine. 2023 June 23;389(10).
2. Dutta D, Lakshmi Nagendra, Anne B, Kumar M, Sharma M, A. B. M. Kamrul‐Hasan. Orforglipron, a novel non‐peptide oral daily glucagon‐like peptide‐1 receptor agonist as an anti‐obesity medicine: A systematic review and meta‐analysis. Obesity science & practice [Internet]. 2024 Feb 26 [cited 2026 July 29];10(2). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10896246/
3. Lilly E. Find Lilly Clinical Trials | Learn About Our Research [Internet]. Lilly Trials. 2026 [cited 2026 July 29]. Available from: https://trials.lilly.com/en-US/trial/609396
4. Galindo RJ, Alice, Longuet C, Ai M, Coskun T, Malik R, et al. Insights into the Mechanism of Action of Tirzepatide: A Narrative Review. Diabetes Therapy. 2025 Nov 6;.
5. MHRA. MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss [Internet]. GOV.UK. 2023 Nov [cited 2026 July 29]. Available from: https://www.gov.uk/government/news/mhra-authorises-diabetes-drug-mounjaro-tirzepatide-for-weight-management-and-weight-loss
6. England N. NHS England » Weight management injections [Internet]. England.nhs.uk. 2025 [cited 2026 July 29]. Available from: https://www.england.nhs.uk/ourwork/prevention/obesity/medicines-for-obesity/weight-management-injections/
7. DailyMed - FOUNDAYO- orforglipron tablet, film coated [Internet]. Nih.gov. 2026 [cited 2026 July 29]. Available from: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8ac446c5-feba-474f-a103-23facb9b5c62
8. Mounjaro KwikPen 10mg solution for injection in pre-filled pen - Summary of Product Characteristics (SmPC) - (emc) [Internet]. www.medicines.org.uk. [cited 2026 July 29]. Available from: https://www.medicines.org.uk/emc/product/15484/smpc#gref
9. Tirzepatide for managing overweight and obesity [Internet]. Nih.gov. National Institute for Health and Care Excellence (NICE); 2024 Dec [cited 2026 July 29]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK611612/
10. Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, et al. Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine [Internet]. 2022 June 4 [cited 2026 July 29];387(3):205–16. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
11. Wharton S, Aronne LJ, Stefanski A, Alfaris NF, Ciudin A, Yokote K, et al. Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment. New England Journal of Medicine. 2025 Sept 16;.
12. Package leaflet: Information for the patient Mounjaro ® 2.5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 7.5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 10 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 12.5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 15 mg KwikPen ® solution for injection in pre. In [cited 2026 July 29]. Available from: https://www.medicines.org.uk/emc/files/pil.15481.pdf