Foundayo (orforglipron) side effects and how to deal with them

Foundayo is a daily tablet manufactured by Eli Lilly. It’s prescribed to help reduce body weight alongside diet and activity changes. It can cause side effects, like all medicines, particularly in the first few weeks or after a dose increase. Most are mild, short-lived, and linked to how medication changes the way your appetite and digestion work.

Most of this is manageable once you know what you’re dealing with. This guide covers the most common Foundayo side effects, how to ease them, and when it’s best to speak to a clinician.

What are the common Foundayo side effects?

Nausea, vomiting, constipation, diarrhoea, indigestion, and stomach pain are the most common side effects. These may affect more than 1 in 10 people and are usually mild to moderate.

Most happen because orforglipron (the active ingredient) slows how quickly food leaves your stomach. That is part of how it helps you feel fuller for longer, but your body takes time to adjust.

The other side effects reported in clinical trials affect up to 1 in 10 people. These include:

• bloating and wind
• burping
• dizziness
• hair loss, which is temporary and linked to weight loss, not the medication itself
• headaches
• heartburn/acid reflux
• low blood pressure
• tiredness

Side effects are usually most noticeable in the first few weeks and in the days after each dose increase. For most people, though, they tend to ease as the body settles.

"Many people worry when they experience side effects, but they're a common part of treatment with medications like Foundayo. Most side effects are short-lived and tend to settle over time, particularly when dose increases are introduced gradually. If you do experience symptoms, try not to panic. In many cases, it’s simply a sign your body is getting used to the treatment”

Niya MansuriPrescribing Pharmacist

Foundayo side effects vs other weight loss medication

Foundayo, Wegovy, and Mounjaro all belong to a group of medicines called a glucagon-like-peptide-1 (GLP-1) receptor agonists. However, they contain different active ingredients.

While Foundayo contains orforglipron, both Wegovy pills and Wegovy injections contain semaglutide, and Mounjaro contains tirzepatide, which works on two hormones rather than one. Even though they have different active ingredients, their side effects overlap a lot because they all act on appetite and digestion in a similar way.

Here’s how the most commonly reported side effects compare:

Very common means it may be experienced by more than 1 in 10 people. Common means up to 1 in 10 people.

Dealing with Foundayo side effects

Most of these side effects can be eased at home. Adjusting what and how you eat, staying well hydrated, and giving your body time at each dose are what help the most. Always speak to your clinician before starting any new medication, including anything bought over the counter.

Nausea

Nausea (feeling sick) is one of the most reported Foundayo side effects, and if you are dealing with it, you’re certainly not alone. It’s more common after eating a rich or large meal, and it usually peaks in the first few days after a dose increase before easing off again.

• Medication: our clinicians may be able to prescribe anti-sickness medication free of charge if symptoms are affecting daily life.
• Home remedies: ginger or peppermint tea can help settle your stomach, and some people find acupressure bands useful.
• Lifestyle adjustments: eat smaller portions more often, slow down at mealtimes, avoid fatty foods, and stay upright after eating.

Constipation

Constipation happens because food moves more slowly through your digestive system. Eating less overall and taking in less fibre and fluid can make this more common. Also, it tends to hang around longer than other digestive side effects, so it’s one worth getting ahead of instead of waiting it out.

• Medication: the NHS suggests diet and lifestyle changes first, then a laxative if those do not help. Most laxatives will work within three days but are meant for short-term use, so it’s best to speak to one of our expert clinicians before taking them.
• Home remedies: warm drinks in the morning, prunes, and a glass of water before each meal can all help to get things moving.
• Lifestyle adjustments: build up fibre gradually with whole grains, vegetables, beans, and fruit. It’s also best to stay hydrated and regularly do some gentle exercise.

Indigestion and heartburn

A burning feeling in your chest after eating, or when you lie down in the evening, is a fairly common one early on. Indigestion and heartburn tend to show up alongside the other digestive effects, and usually ease at the same time.

• Medication: alginates and antacids can help to ease symptoms. They are typically taken after meals and before bedtime. Our clinicians can advise if something stronger would suit you.
• Home remedies: raise the head of your bed by 10 to 20cm using wood or books, so your chest sits above your waist. Extra pillows do not have the same effect and can make symptoms worse.
• Lifestyle adjustments: cut back on rich, acidic, and spicy foods. It’s best to also eat slowly, avoid eating late, and to limit alcohol and caffeine.

Stomach pain and bloating

Feeling uncomfortably full, or bloated after eating less than you normally would, is common in the early weeks. If you’re experiencing this, you’re certainly not alone, and it usually settles as your body adjusts.

• Medication: our clinicians can advise what might help with mild cramping alongside Foundayo.
• Home remedies: a warm compress on your stomach, or peppermint tea after meals, can be soothing.
• Lifestyle adjustments: eat smaller meals, stop when comfortably full, and take a short walk after eating.

Severe or persistent stomach pain is not expected and should be checked by a doctor if you experience this.

Diarrhoea

Diarrhoea is common in the early weeks, and you may notice looser or more frequent bowel movements as your digestive system adapts. It’s usually nothing to worry about, and for most people goes away once your body adjusts.

• Medication: Loperamide may help occasional episodes, and rehydration sachets can replace lost fluids and salt. Always read the patient leaflet, and speak to one of our clinicians before using either regularly.
• Home remedies: sip water or squash slowly and steadily throughout the day instead of drinking large amounts at once. The NHS advises against fruit juice and fizzy drinks, which can make diarrhoea worse.
• Lifestyle adjustments: eat when you feel able to and try to avoid fatty or spicy foods until the symptoms settle.

If your diarrhoea lasts more than a few days or you find you cannot keep fluids down, speak to one of our clinicians.

Headaches and dizziness

Headaches and dizziness are usually linked to eating less, drinking less, or changes in blood sugar rather than the medication itself.

• Medication: Paracetamol or Ibuprofen may help occasional headaches.
• Home remedies: have a glass of water and eat a small snack, standing up slowly if you feel lightheaded.
• Lifestyle adjustments: ensure you eat regularly, even when your appetite is low. Keep fluids topped up, and avoid leaving long gaps between meals.

Tiredness and hair loss

Tiredness is often a sign you’re not eating enough, particularly if your appetite has dropped away quickly and you haven’t adjusted what you’re eating to match. Also, hair loss is usually temporary and linked to losing weight quickly rather than Foundayo itself.

• Medication: there is no specific treatment for either, though our clinicians can check whether anything else is contributing.
• Home remedies: slow down, prioritise sleep, and choose something like walking or swimming over pushing through more intense workouts.
• Lifestyle adjustments: make sure you’re getting enough protein. The NHS has guidance on how much you should be eating.

We’re here to help!

You do not have to manage side effects alone. As part of your Foundayo treatment plan, myBMI offers free unlimited side effect support on request.

If something is not sitting right, please speak to our pharmacy team at your consultation or through your account and, if appropriate, they can prescribe treatment to help, whether that’s anti-sickness medication, something for heartburn, or another option.

If you’re considering Foundayo or are already taking it and want that support behind you, you can see what’s included in our treatment plans.

Are there more serious side effects of Foundayo?

The side effects below are rare, and most people taking Foundayo will never come across them, but they’re the ones to know the signs of so you can act quickly if something doesn’t feel right:

• Inflammation of the pancreas (pancreatitis) affects up to 1 in 100 people. It usually causes severe stomach pain that may spread to your back, often with ongoing vomiting, and does not settle with rest or changes made to your diet.
• Gallbladder problems, including gallstones, can develop when weight loss happens quickly. Symptoms include pain on the upper right side of your stomach, sometimes with fever or yellowing of the skin or eyes.
• Low blood sugar is uncommon on Foundayo alone, but more likely if you are also taking medication for diabetes. Please let your prescriber know if you are on any diabetic medication or have any changes to your medication regime.
• Eye disorders are rare, but non-arteritic anterior ischaemic optic neuropathy (NAION) can occur. This is a condition that can cause decreased vision, including permanent loss of vision. Rare cases have been reported with medicines that act on the GLP-1 receptor. If you experience a sudden change or loss of vision, seek urgent medical attention.
• Dehydration from ongoing vomiting or diarrhoea can impact your kidneys. The signs to watch for are dark urine, passing very little, and feeling weaker than usual.
• Allergic reactions are rare, but can be serious. Mild reactions may cause a rash or itching, while severe reactions can cause swelling of the face, lips or throat, and difficulty breathing.

Eli Lilly (the manufacturer) also advises that Foundayo is not suitable for people with a personal or family history of medullary thyroid carcinoma, a rare form of thyroid cancer, or an inherited condition called multiple endocrine neoplasia syndrome type 2 (MEN 2). This warning comes from animal studies, and it has not been confirmed whether the same risk applies to people. If you’d like to know more about this, Macmillan Cancer Support has lots of information. Our clinicians will ask about your medical history before prescribing.

"Reading about serious side effects can understandably feel worrying, but it's important to remember that these events are rare. The vast majority of people taking Foundayo will only experience mild side effects. While it's important to be aware of the warning signs and know when to seek medical advice, serious side effects affect only a small number of people and should be viewed in the context of the many people who take treatment safely under clinical supervision."

Niya MansuriPrescribing Pharmacist

When should I contact my doctor about Foundayo side effects?

Contact a doctor straight away if you have severe stomach pain spreading to your back, ongoing vomiting that stops you eating or drinking, or signs of dehydration such as dark urine.

You should also seek urgent medical help if you notice:

• pain on the upper right side of your stomach, particularly after eating
• yellowing of your skin or the whites of your eyes
• sudden changes to your vision
• a lump or swelling in your neck, hoarseness, or trouble swallowing
• shaking, sweating, confusion, or feeling faint (which can indicate low blood sugar)

Call 999 if you have swelling of your face, lips, or throat, or difficulty breathing, as these can be signs of a severe allergic reaction. Do not drive yourself to hospital.

For milder symptoms that are not improving, speak to our clinical team as there’s often something that can be done.

If you are weighing up whether Foundayo is right for you, our clinicians will review your medical history and let you know whether it’s suitable.

Frequently asked questions

How long do Foundayo side effects last?

Most people tend to experience stronger side effects in the first few weeks. However, these tend to ease as the body adjusts. When a dose is increased, side effects may return briefly before settling again and are not expected to continue long-term.

Do side effects mean Foundayo is working?

No. Side effects are not a sign of how well treatment is working, and plenty of people lose weight without experiencing any.

Does alcohol make side effects worse?

Alcohol may worsen nausea, reflux, and dizziness, whilst also adding to the risk of dehydration if you’re already dealing with vomiting or diarrhoea. Drinking in moderation, or not at all for the first few weeks while your body adjusts, may make things more comfortable.

Sources:

• Foundayo Medication Guide. (2026) Eli Lilly. [Accessed 22 August 2026]
• Foundayo 0.8 mg film-coated tablets – Patient Information Leaflet. (2026) Electronic Medicines Compendium. [Accessed 22 August 2026]
• GLP-1 medicines for weight loss and diabetes: what you need to know. (2026) GOV.UK. [Accessed 22 August 2026]
• Wegovy 25 mg tablets. (2026) Electronic Medicines Compendium. [Accessed 23 August 2026]
• Water, drinks and hydration. (2024) NHS. [Accessed 23 August 2026]
• Feeling sick (nausea). (2025) NHS. [Accessed 22 August 2026]
• Using pressure points to relieve nausea. (2024) NHS. [Accessed 22 August 2026]
• Constipation. (2026) NHS. [Accessed 22 August 2026]
• Heartburn and acid reflux. (2025) NHS. [Accessed 23 August 2026]
• Antacids. (2025) NHS. [Accessed 22 August 2026]
• Imodium Original 2mg Capsules – Patient Leaflet. (2024) Electronic Medicines Compendium. [Accessed 24 August 2026]
• Diarrhoea and vomiting. (2025) NHS. [Accessed 22 August 2026]
• Dizziness. (2025) NHS. [Accessed 22 August 2026]
• Protein. (2025) NHS. [Accessed 22 August 2026]
• Type 2 diabetes. (2025) NHS. [Accessed 23 August 2026]
• Diabetic retinopathy. (2025) NHS. [Accessed 23 August 2026]
• Thyroid cancer. (2025) NHS. [Accessed 23 August 2026]
• Medullary thyroid cancer. (2025) Macmillan Cancer Support. [Accessed 23 August 2026]
• Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen. (2026) Electronic Medicines Compendium. [Accessed 22 August 2026]
• Wegovy 0.25 mg, FlexTouch solution for injection in pre-filled pen. (2026) Electronic Medicines Compendium. [Accessed 22 August 2026]