¹Ayoub, Mark, et al. "Pancreatitis Risk Associated with GLP-1 Receptor Agonists, Considered as a Single Class, in a Comorbidity-Free Subgroup of Type 2 Diabetes Patients in the United States: A Propensity Score-Matched Analysis." Journal of Clinical Medicine, vol. 14, no. 3, 1 Feb. 2025, p. 944, doi.org/10.3390/jcm14030944.
Been wanting to try weight loss medication but not a fan of needles? There's good news: a new generation of oral GLP-1 weight loss pills is here.
Orforglipron, sold under the brand name Foundayo in the US, was approved in April 2026. It isn't yet available in the UK, but approval is expected by late 2026. Like any medicine, it comes with side effects. Here's what we know about orforglipron (Foundayo) side effects so far.
Key Takeaways
- Orforglipron is a GLP-1 receptor agonist weight loss pill
- Common side effects include digestive issues like nausea, constipation, and diarrhoea, similar to other GLP-1 injections
- Serious side effects like pancreatitis and gallbladder inflammation are rare
- Most side effects occur when beginning treatment or when the dose increases, and often improve as the body adjusts
- Orforglipron was approved in the US in April 2026 under the brand name Foundayo; UK availability is expected by late 2026
Treatment management
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What is orforglipron and how does it work?
Orforglipron, sold as Foundayo in the US, is a once-daily weight loss pill that belongs to a family of medicines called GLP-1 receptor agonists.
If that sounds familiar, that's because popular medicines like Wegovy and Mounjaro are also GLP-1 receptor agonists (technically, Mounjaro weight loss injections are GLP-1/GIP receptor agonists).
These medicines work by mimicking GLP-1, a natural hunger hormone (Mounjaro also mimics the hormone GIP). This suppresses your appetite and keeps cravings at bay, so you eat less.
Unlike Wegovy and Mounjaro injections, orforglipron is taken as a daily tablet. And unlike the Wegovy pill and Rybelsus (the other oral GLP-1 medications), Foundayo can be taken at any time of day, with or without food.
For the full guide to how orforglipron works, dosing, and effectiveness, see our orforglipron medication page.
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Common side effects of orforglipron (Foundayo)
Orforglipron side effects mostly affect the digestive system as your body adjusts to the medication. The most commonly reported side effects include:
- Nausea
- Constipation
- Diarrhoea
- Vomiting
- Indigestion
- Stomach (abdominal) pain
- Headache
- Swollen belly (bloating)
- Feeling tired
- Belching
- Heartburn
- Gas
- Hair loss
Most symptoms were mild to moderate in clinical trials and tended to ease over time. They were broadly comparable to Wegovy side effects and Mounjaro side effects.
In the ACHIEVE-4 trial, around 10.6% of people stopped taking orforglipron over 52 weeks because of side effects. The majority continued treatment.
Side effects support at Voy
"If you're using Voy and you experience any side effects, rest assured that our expert clinicians are just a message or phone call away. They can adjust your dose, prescribe medication to ease your symptoms, or simply offer reassurance.
Everyone responds differently to weight loss treatment and we'll help you find what feels right for you."
When do the side effects start and how long do they last?
Orforglipron side effects tend to come on when you first start the medicine or increase your dose. They’re usually mild to moderate and often improve as your body adapts.
Like other GLP-1 medicines, orforglipron is started at a lower dose and increases gradually over time. This slow build-up helps your body get used to the medicine and can reduce gut-related side effects.
Why do these side effects happen?
Orforglipron (Foundayo) works by slowing down digestion and signalling to the brain to curb your appetite, helping you feel fuller for longer and eat less. The same actions that make orforglipron effective for weight loss are also what cause most of its side effects, particularly gut-related ones like nausea, constipation, and bloating.
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Orforglipron isn’t available yet in the UK, but Wegovy and Mounjaro are already helping people lose weight. Start your journey today with proven treatments and support that sticks.
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Rare but serious side effects of orforglipron (Foundayo)
More serious orforglipron (Foundayo) side effects are rare, but it's worth knowing the signs. Based on the Foundayo prescribing information, these include:
- Inflammation of the pancreas (pancreatitis) — severe stomach pain that may spread to the back
- Gallbladder problems — pain in the upper stomach, fever, or yellowing of skin or eyes
- Severe stomach problems — issues that are severe or won't ease over time
- Dehydration leading to kidney problems — from severe nausea, vomiting, or diarrhoea
- Low blood sugar (hypoglycaemia) — particularly if taken with insulin or sulfonylureas (such as gliclazide)
- Serious allergic reactions — swelling of the face, lips, tongue, or throat, or problems breathing or swallowing
- Changes in vision — mainly in people with type 2 diabetes
- Food or liquid getting into the lungs during surgery or procedures that use anaesthesia or deep sedation
Orforglipron also carries a warning about possible thyroid cancer. People with a personal or family history of medullary thyroid cancer (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) shouldn't take orforglipron.
Overall, across more than 11,000 people studied in clinical trials, orforglipron (Foundayo) has shown a consistent safety record.
Can orforglipron cause pancreatitis?
Pancreatitis has occasionally been reported with GLP-1 medicines like Wegovy and Mounjaro, but it remains rare. A few cases have also appeared in orforglipron studies, although numbers are very small.
Large real-world studies suggest GLP-1 medicines do not increase pancreatitis risk. In a major US analysis of over 160,000 people, pancreatitis rates were low and similar between GLP-1 users and non-users.
It's also important to remember that rapid weight loss can increase the risk of gallstones, which are a common trigger for pancreatitis. This means pancreatitis can occur during rapid weight loss from lifestyle changes alone, not just medication.
Overall, pancreatitis with orforglipron (Foundayo) appears to be uncommon.
How to manage orforglipron side effects
Here are some tips for easing orforglipron side effects:
- Follow your prescriber’s dosing advice exactly. Taking a higher strength than prescribed, or moving up too quickly, can bring on side effects
- Have more frequent, smaller meals, and eat them slowly. This can minimise the strain on your gut
- Avoid spicy, greasy, or highly processed foods. They can irritate your stomach
- Taking regular sips of cold water can help with nausea. It can also ease constipation and ensure you’re staying hydrated if you’ve been sick
When to seek medical help
Orforglipron isn't yet available in the UK, but if you're taking it (or any other GLP-1 medicine), seek medical help if:
- Your symptoms aren't going away, are bothering you, or are getting worse
- You have severe pain in your stomach, particularly if it spreads to your back. This can be a sign of pancreatitis or an inflamed gallbladder
- You have swelling in your face, lips, or tongue. These are signs of an allergic reaction. Seek help right away
Your weight loss journey
Orforglipron isn't yet available in the UK, with approval expected by late 2026. But there are plenty of other weight loss medications that can help you reach your goals, and you can get started right now.
At Voy, we offer Wegovy, Mounjaro, and Orlos (orlistat) weight loss tablets. Through our weight loss treatment, we post your medicine each month, with support from our clinical team every step of the way.
Take our short quiz to see if you're eligible.
