Everything you need to know about Orforglipron (Foundayo)

DoktorABC editorial team

Accurate, up-to-date health information written by our editorial team and reviewed by UK-registered prescribers.

What is orforglipron?

Orforglipron is an oral, non-peptide GLP-1 receptor agonist. In the UK, it is available under the brand name Foundayo, manufactured by Eli Lilly and Company.

The MHRA authorised Foundayo on 10 August 2026 for two indications: weight management in eligible adults, and improving blood sugar control in adults with insufficiently controlled type 2 diabetes. The UK was the first country in Europe to license it for either indication.

How does orforglipron work?

Orforglipron mimics the action of GLP-1, a hormone your body produces naturally in the gut after eating. GLP-1 acts on receptors in the brain that regulate appetite and food intake, and it also influences how the body handles blood sugar.

In practice, orforglipron works through several complementary mechanisms:

• Appetite regulation: By activating GLP-1 receptors in areas of the brain that control hunger and satiety, orforglipron reduces the drive to eat and helps you feel full sooner after smaller amounts of food. Many people notice a reduction in background food preoccupation, sometimes described as quieter food noise.
• Delayed gastric emptying: Orforglipron slows the rate at which food moves from the stomach into the small intestine. This extends the feeling of fullness after meals and reduces the speed at which glucose enters the bloodstream.
• Glucose-dependent insulin effects: Orforglipron stimulates insulin release in response to elevated blood sugar and reduces glucagon, a hormone that raises blood sugar. These effects only occur when blood sugar is already elevated, which limits the risk of hypoglycaemia in people without diabetes. The overall effect is a sustained reduction in calorie intake, which, when combined with dietary changes and increased physical activity, supports weight loss over time.
• What orforglipron does not do: It is not a fat burner and does not directly target or break down stored fat. Weight loss occurs because the medicine supports a calorie deficit, not because it acts on fat tissue directly.

Foundayo tablets: form, strengths, and how to take them

Foundayo is a once-daily prescription tablet, not an injection. It is available in six strengths: 0.8 mg, 2.5 mg, 5.5 mg, 9 mg, 14.5 mg, and 17.2 mg. The maximum licensed dose is 17.2 mg once daily.

How to take it: One tablet is taken orally once daily, with or without food, at any time of day. There are no restrictions on what you eat, drink, or take alongside it in terms of timing, which distinguishes it from the Wegovy pill. Swallow the tablet whole. Do not split, crush, or chew it.

Dose escalation: Treatment starts at the lowest dose and is increased gradually over several months to reduce the risk of gastrointestinal side effects. The standard titration schedule, based on the UK SmPC published on the electronic Medicines Compendium (medicines.org.uk, last updated 14 August 2026), is as follows:

This table is a reference, not a self-titration guide. Your prescriber will determine the appropriate dose and escalation schedule for your individual circumstances. Some people achieve a satisfactory response at an earlier step and may remain there. The maximum dose is not an automatic target.

Who may be eligible in the UK?

The UK licence for Foundayo for weight management covers adults with:

• A BMI of 30 kg/m² or above, or
• A BMI of 27 to 29.9 kg/m² with at least one weight-related comorbidity, such as type 2 diabetes, high blood pressure, high cholesterol, obstructive sleep apnoea, or cardiovascular disease

Treatment must be used as an adjunct to a reduced-calorie diet and increased physical activity. It is not a standalone treatment.

Clinical evidence and realistic results

The main evidence for orforglipron's weight management effect comes from the Phase 3 ATTAIN-1 trial, published in the New England Journal of Medicine in 2025. ATTAIN-1 enrolled 3,127 adults with obesity but without type 2 diabetes. Participants were randomly assigned to one of three doses of orforglipron or placebo and followed for 72 weeks. All participants received dietary and lifestyle support alongside the medicine.

At 72 weeks, the results across the intention-to-treat population were:

• Orforglipron 6 mg: average body weight reduction of 7.9%
• Orforglipron 12 mg: average body weight reduction of 10.1%
• Orforglipron 36 mg (equivalent to the 17.2 mg licensed tablet dose): average body weight reduction of 11.1%
• Placebo: average body weight reduction of 2.1%

Among participants who completed the full 72-week trial on the highest dose, average weight loss was 12.4%.

In terms of responder rates at the highest dose, 77.1% of participants lost at least 5% of their starting body weight, 59.6% lost at least 10%, 39.6% lost 15% or more, and 20.1% lost at least 20%.

Beyond weight, ATTAIN-1 also showed improvements in waist circumference, non-HDL cholesterol, triglycerides, and systolic blood pressure across all doses.

What these figures mean in practice: These are averages from a controlled clinical trial in which all participants received dietary and lifestyle support. Individual outcomes vary. The figures should not be used to predict what any specific person will lose, and achieving the trial average is not guaranteed. Results depend on adherence, dietary changes, physical activity, starting weight, and individual biological response.

Side effects and safety

As with all medicines, Foundayo can cause side effects. The information below is drawn from the UK SmPC published on the electronic Medicines Compendium (medicines.org.uk, last updated 14 August 2026). Always read the patient information leaflet supplied with your medication and contact your prescriber with any concerns. Do not attempt to self-diagnose or self-manage symptoms that concern you.

Common gastrointestinal side effects

In the weight management studies, gastrointestinal disorders occurred in 60 to 69% of people taking orforglipron, compared with 36% taking placebo. The most frequently reported effects were nausea, constipation, diarrhoea, vomiting, abdominal pain, dyspepsia (indigestion), and eructation (burping). These were mostly mild to moderate in severity. The incidence was highest during the dose escalation period and decreased over time as the body adjusted.

Approximately 6 to 7% of participants on the higher doses discontinued treatment due to gastrointestinal side effects, compared with 0.6% on placebo.

Other commonly reported side effects include headache, fatigue, and hair loss (alopecia), which has been reported with GLP-1 medicines generally and is thought to be related to the physiological effects of rapid weight loss rather than a direct drug effect.

Clinically important warnings

• Gastrointestinal reactions: Severe gastrointestinal events were reported in approximately 3% of people taking orforglipron in clinical trials. If you experience severe or persistent vomiting, diarrhoea, or abdominal pain, stop taking the medicine and contact your prescriber or seek medical attention.
• Pancreatitis: Cases of pancreatitis have been reported with GLP-1 medicines. If you experience severe and persistent abdominal pain, with or without vomiting, stop taking Foundayo and seek urgent medical attention. Pancreatitis is uncommon but serious.
• Gallbladder problems: Cholelithiasis (gallstones) and cholecystitis (gallbladder inflammation) have been associated with GLP-1 medicines, in part due to rapid weight loss. Report significant right-sided upper abdominal pain to your prescriber.
• Tachycardia: An increased heart rate has been observed with orforglipron. If you notice a persistently fast, irregular, or pounding heartbeat, contact your prescriber.
• Dehydration: Persistent nausea, vomiting, or diarrhoea can lead to dehydration, which can in turn affect kidney function. Stay well hydrated, particularly during dose increases, and seek medical attention if you are unable to keep fluids down.
• Vision changes: Sudden changes in vision have been reported with GLP-1 medicines. Seek prompt medical attention if this occurs.

Contraindications and precautions

Foundayo should not be used in people who:

• Are pregnant or breastfeeding. There are no adequate data on the use of orforglipron during pregnancy. Animal studies have shown reproductive toxicity. Orforglipron should not be used during pregnancy and should be stopped before trying to conceive. Discuss the appropriate washout period with your prescriber.
• Have a known hypersensitivity to orforglipron or any of the excipients

Foundayo should be used with caution and only after careful prescriber assessment in people with:

• A history of or risk factors for pancreatitis
• Gallbladder disease
• Significant kidney impairment
• Severe gastrointestinal conditions

Oral contraceptive interaction: Because orforglipron delays gastric emptying, it can reduce the absorption of oral hormonal contraceptives. The UK SmPC advises that people using oral contraceptives should switch to a non-oral method or add a barrier method of contraception for 30 days after starting Foundayo and for 30 days after each dose increase.

Other drug interactions

• Strong CYP3A4 inhibitors that also inhibit OATP1B (such as ritonavir) should be avoided. If you are taking a strong CYP3A4 inhibitor without OATP1B inhibition, the maximum dose of Foundayo is capped at 9 mg, not 17.2 mg.
• Strong CYP3A4 inducers should be avoided, as they reduce orforglipron exposure.
• Simvastatin: Do not exceed 20 mg of simvastatin once daily when taking Foundayo.
• Insulin or insulin secretagogues: Concurrent use may increase the risk of hypoglycaemia. A dose reduction of insulin or the secretagogue may be needed.

Always disclose your full medication list, including over-the-counter medicines and supplements, to your prescriber before starting Foundayo.

Surgery and procedures: If you are planning a surgical procedure requiring anaesthesia, inform your surgical team that you are taking Foundayo, as delayed gastric emptying can affect anaesthetic management. Your prescriber can advise on whether a temporary pause in treatment is appropriate.

How long does it take to work?

The question of when results will be noticeable has two parts, appetite and glucose effects, and visible weight change.

Many people notice a reduction in appetite, fewer cravings, or an earlier sense of fullness within the first few weeks of starting Foundayo, even at the lowest doses. Blood sugar improvements in people with type 2 diabetes may also appear relatively early in treatment.

Visible weight change takes longer. Weight loss accumulates gradually during the titration phase as doses increase, and the most significant changes typically become apparent from three months onwards, with results continuing to build over the full 72-week period studied in ATTAIN-1.

Individual variation is considerable. Factors including starting weight, dietary adherence, activity levels, metabolic rate, and how well the medicine is tolerated during titration all influence the pace and scale of results. The titration schedule itself means the full therapeutic dose is not reached until several months into treatment, and results that seem modest early on often build substantially over time.

Orforglipron vs tirzepatide

Orforglipron (Foundayo) and tirzepatide (Mounjaro) are both MHRA-approved for weight management in the UK, and both are manufactured by Eli Lilly. They are different medicines with different mechanisms, delivery routes, and evidence bases.

On the efficacy figures: The weight loss data above come from separate trials with different populations and durations. They are not the result of a head-to-head comparison in people without diabetes. The ACHIEVE-3 trial compared the two medicines in people with type 2 diabetes, a different population from the weight management trials. Cross-trial comparisons suggest tirzepatide produces greater average weight loss at its maximum dose, but individual response varies and these figures cannot reliably predict what any one person will experience.

On mechanism: Tirzepatide's dual GIP and GLP-1 receptor action is thought to explain its stronger average efficacy signal in trials. Orforglipron activates only the GLP-1 receptor. Neither mechanism is inherently superior, and factors such as tolerability, convenience, and daily routine compatibility are equally important considerations in treatment choice.

The right choice between these treatments depends on your individual health picture, preferences, and lifestyle. A UK-registered prescriber can help you weigh the options in the context of your specific circumstances.

Accessing orforglipron in the UK

Foundayo is a prescription-only medicine. It cannot be obtained without a valid prescription from a UK-registered prescriber following a medical assessment.

Legitimate routes to access in the UK:

• A UK-registered private online clinic or prescribing service, following a medical assessment
• A GP, where they are willing to prescribe it privately (NHS prescribing is not currently available)
• NHS specialist services, if and when NICE recommends it and local commissioning confirms availability

Final thoughts

Orforglipron (Foundayo) is a clinically meaningful addition to the weight management options available in the UK. For people who want the metabolic support of a GLP-1 treatment without needles, refrigeration, or a fasting morning routine, it offers a genuinely different experience from both the injectable options and the Wegovy pill.

The clinical trial evidence shows meaningful weight loss in a significant proportion of participants, alongside improvements in several cardiometabolic markers. As with all GLP-1 treatments, results depend on adherence, dietary changes, physical activity, and consistent clinical support. The medicine works best as part of a structured approach, not independently of it.

FAQ

The DoktorABC medical advisory board

Dr. Roland Ruiken

Medical advisor, Norway

Dr. Viktor Simunovic

Medical advisor, Croatia

To the medical advisory board