Foundayo has just been approved in the UK, and it's a genuinely new kind of medicine, not just another version of something you've already heard of. Here's what it is, how it works, and what the evidence shows.

What is Foundayo?

Foundayo is the brand name for orforglipron, Eli Lilly's oral GLP-1 receptor agonist. It's a once-daily tablet, but importantly, it isn't a peptide like semaglutide or tirzepatide. That distinction is what makes Foundayo behave differently from both injectable GLP-1 medicines and oral Wegovy.

How it works

Orforglipron is a small-molecule GLP-1 receptor agonist, the first of its kind to be approved. The GLP-1 medicines you already know, semaglutide, liraglutide, tirzepatide are peptides: chains of amino acids that would normally be broken down by stomach acid and digestive enzymes. That's why they're usually injected, or, in the case of oral Wegovy, formulated with special absorption technology and a strict fasting rule to get the peptide past the stomach lining intact.

Orforglipron is a much simpler molecule chemically. It survives the stomach and is absorbed like an ordinary tablet, think aspirin or paracetamol, which is why it can be taken with or without food, at any time of day.

Once it's absorbed, it works the same way any GLP-1 medicine does:

• It mimics the gut hormone GLP-1, acting on receptors in the brain to increase feelings of fullness and reduce appetite and food cravings
• It slows down how quickly the stomach empties, so people feel full for longer after eating
• In people with type 2 diabetes, it helps the pancreas release more insulin when blood sugar is high

In short: the same mechanism as the injectable GLP-1s people already know, delivered in a tablet that behaves like a normal medicine rather than a specialist peptide formulation.

The evidence

Foundayo's weight-loss evidence comes from Lilly's ATTAIN phase 3 programme. The headline trial is:

ATTAIN-1 (adults with obesity or overweight, no diabetes)

• 3,127 participants with obesity or overweight plus at least one weight-related complication (e.g. hypertension, high cholesterol, sleep apnoea, cardiovascular disease), and no diabetes
• 72 weeks, randomised, double-blind, placebo-controlled
• Published in full in the New England Journal of Medicine
• At the highest dose, 59.6% of participants lost at least 10% of their body weight, and 39.6% lost at least 15%

On average, that works out to around 11–12% body weight loss at the top dose over 72 weeks, alongside meaningful improvements in blood pressure, triglycerides, cholesterol and inflammatory markers. That's slightly below oral Wegovy's headline 13.6% figure, but still a genuinely competitive result.

Side effects

As with every GLP-1 medicine, gastrointestinal side effects are the most common. They're dose-related and tend to settle over the first few weeks at each new dose step.

Most GI reactions were mild (around 60%) or moderate (36%), with only 4% classed as severe. 8% of people on Foundayo stopped treatment because of side effects, compared with 3% on placebo, and GI symptoms were the main driver of that.

Less common but important warnings

These mirror warnings that are already familiar from injectable GLP-1s:

• Acute pancreatitis — treatment should stop and medical review sought if suspected
• Gallbladder disease — cholelithiasis reported in 1% of patients (vs 0.7% on placebo)
• Acute kidney injury — usually secondary to dehydration from vomiting or diarrhoea, so hydration matters
• Hypoglycaemia — increased risk when combined with insulin or sulfonylureas; low risk in people without diabetes
• Hypersensitivity reactions, including rare reports of anaphylaxis and angioedema
• Diabetic retinopathy — rapid improvement in blood sugar can, as with semaglutide, transiently worsen existing retinopathy in those with a history
• Not recommended in severe gastroparesis (delayed stomach emptying)
• Thyroid C-cell tumour warning — a class-wide signal carried over from rodent studies of GLP-1 receptor agonists; human relevance hasn't been established, but the same contraindication applies for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2
• Pulmonary aspiration risk under anaesthesia or deep sedation, due to delayed gastric emptying — anyone taking Foundayo should flag this ahead of any surgical or endoscopic procedure

How to take it

• One tablet, once a day
• Can be taken with or without food, at any time of day, no fasting window, no water-volume rule, and no 30-minute wait before eating. This is the headline practical difference from oral Wegovy
• Swallow the tablet whole, don't break, crush or chew it
• Only one strength is taken at a time; strengths aren't combined
• If a dose is missed, follow the specific guidance in the UK patient information leaflet once it's published, don't improvise or double up without checking

Dose titration schedule

Foundayo is titrated slowly, in the same way as Mounjaro and Wegovy, to help minimise GI side effects. Every step up requires a minimum of 30 days at the current dose.

The key headlines

1. Foundayo an oral small-molecule GLP-1 medicine approved in the UK. MHRA approval came through on 10 August 2026. It's a genuinely different kind of tablet to oral Wegovy.
2. No fasting, no water rules, take it any time of day. This is Foundayo's main practical advantage over oral Wegovy, which requires an empty stomach, a small amount of water, and a 30-minute wait before eating.
3. Meaningful weight loss with real cardiometabolic benefit. Around 11–12% average body weight loss at the top dose over 72 weeks, alongside meaningful drops in blood pressure, triglycerides, cholesterol and inflammatory markers.
4. Same eligibility bar as existing GLP-1 options. BMI ≥30, or 27+ with a weight-related comorbidity, nothing new for screening.
5. Not yet available on the NHS. NICE guidance isn't expected until 18 November 2026, so for now Foundayo sits alongside other private-only options.
6. Switching pathways exist for people already on Mounjaro, injectable Wegovy or oral Wegovy, but every switch still goes through clinical review rather than being self-service. More detail on this to follow.