Jump to: What the trials found | How Foundayo compares to the Wegovy pill | Switching from injectables to a pill | How orforglipron works differently from semaglutide | Side effects | Limitations to keep in mind | What this means for the UK | Take home message
The FDA has approved Foundayo (orforglipron), a once-daily GLP-1 weight-loss pill that can be taken at any time of day without food or water restrictions.1
In the Phase 3 ATTAIN-1 trial, adults living with obesity taking the highest dose lost an average of 11.2% of their body weight over 72 weeks.2
Foundayo is the second oral GLP-1 approved for weight loss in the U.S., following the Wegovy pill (oral semaglutide) in December 2025.
It was approved on 1 April 2026 under the FDA’s new National Priority Voucher programme, making it the fastest new drug approval since 2002.1
The weight loss is lower than that produced by injectable Mounjaro or Wegovy. The difference is in convenience: there are no injections, no fasting, and no timing requirements.
For people who have avoided GLP-1 treatment because of needles or the strict dosing routine of the Wegovy pill, this removes both barriers.
Important safety information: Foundayo (orforglipron) is a prescription-only medication approved in the U.S. for weight management. It’s not yet approved in the UK. This article is for informational purposes only. Always consult with your healthcare provider before starting any new medication.
What the trials found
Foundayo’s approval is based on the ATTAIN clinical trial programme, which studied orforglipron across multiple populations.
The main weight-loss trial, ATTAIN-1, enrolled 3,127 adults with obesity or overweight (with at least one weight-related condition) who did not have type 2 diabetes.
Participants were randomly assigned to receive orforglipron at one of three doses (6 mg, 12 mg, or 36 mg) or placebo for 72 weeks, alongside a healthy diet and physical activity.2
Weight loss results by dose:
- 7.5% average weight loss with 6 mg
- 8.4% with 12 mg
- 11.2% with 36 mg (approximately 25 lbs)
- 2.1% with placebo
Among participants in the highest-dose group who stayed on treatment for the full 72 weeks, the average weight loss was 12.4% (approximately 27 lbs).2
At the 36 mg dose, 54.6% of participants lost at least 10% of their body weight, 36% lost at least 15%, and 18.4% lost at least 20%.2
The trial also found improvements in waist circumference, blood pressure, triglycerides, and non-HDL cholesterol across all doses.
A separate trial, ATTAIN-2, studied orforglipron in adults with type 2 diabetes and obesity. At the highest dose, participants lost an average of 10.5% of their body weight over 72 weeks, alongside significant reductions in HbA1c.3
How Foundayo compares to the Wegovy pill
There are now two oral GLP-1 medications approved for weight loss in the U.S. They work through the same receptor (GLP-1) but differ in how they’re taken and the amount of weight loss they produce.
The Wegovy pill (oral semaglutide 25 mg) produced 13.6% average weight loss over 64 weeks in the OASIS 4 trial.4 That’s higher than Foundayo’s 11.2% over 72 weeks.
The trials weren’t head-to-head comparisons, so direct comparison isn’t appropriate, but the difference is consistent across the data.
Still, there’s a difference in how you take the medications. The Wegovy pill must be taken first thing in the morning on an empty stomach, with no more than 120 ml of water, followed by a 30-minute fast. If these conditions aren’t met, the medication may not be absorbed properly.
Foundayo can be taken at any time of day, with or without food, with no water restrictions.1 If you miss a dose, you can take it as soon as you remember rather than skipping until the next day.
The Wegovy pill’s fasting requirement is a known barrier to adherence, particularly for people who take other morning medications or who find the routine difficult to maintain.
The Wegovy pill also requires refrigeration in some markets, while Foundayo tablets can be stored at room temperature.
Switching from injectables to a daily pill for maintenance
One of the most clinically useful findings from the ATTAIN programme came from ATTAIN-MAINTAIN, a trial that tested a new treatment model: starting with an injectable GLP-1 for initial weight loss, then switching to oral orforglipron (Foundayo) for long-term maintenance.5
Participants who had already lost weight on injectable Wegovy or Mounjaro were re-randomised to receive either orforglipron or placebo for 52 weeks.
Those who switched from Wegovy to orforglipron regained an average of just 0.9 kg over 52 weeks, maintaining nearly all of their previous weight loss.5
A common concern with GLP-1 medications is what happens when you stop or reduce treatment.
The STEP 1 extension trial showed that people who stopped taking injectable semaglutide regained around two-thirds of the weight they had lost within a year.6
ATTAIN-MAINTAIN suggests a potential alternative: rather than staying on injections indefinitely or stopping and risking regain, people could transition to a daily pill that maintains their weight loss in the long term.
How orforglipron works differently from semaglutide
Orforglipron and semaglutide both mimic the hormone GLP-1, reducing appetite and slowing digestion. The difference is in their molecular structure.
Semaglutide is a peptide, a modified version of the natural GLP-1 hormone. Peptides are broken down by stomach acid, which is why injectable semaglutide bypasses the gut entirely and why the Wegovy pill needs the SNAC absorption enhancer and strict fasting conditions to work.
Orforglipron is a small molecule, not a peptide. It was designed to be taken orally, and it doesn’t get degraded by digestive enzymes, which means it can be absorbed reliably regardless of whether there’s food in your stomach.2
Orforglipron is also a GLP-1 agonist only. Injectable Mounjaro (tirzepatide) mimics two hormones: GLP-1 and GIP, which is one reason it produces greater weight loss.
Foundayo doesn’t mimic GIP, which partly explains the lower weight-loss figures compared to Mounjaro.
Side effects
The side-effect profile is consistent with that of other GLP-1 medications. The most common side effects in the ATTAIN trials were nausea, constipation, diarrhoea, vomiting, indigestion, and abdominal pain, occurring most frequently during dose escalation and generally rated as mild to moderate.2
Hair loss is also listed as a common side effect of Foundayo, which was not a prominent finding in the injectable GLP-1 trials.1
Treatment discontinuation due to adverse events ranged from 5.3% to 10.3% across the orforglipron dose groups, compared to 2.7% with placebo.2
Foundayo carries the same boxed warning as other GLP-1 medications regarding thyroid C-cell tumours observed in animal studies. The medication isn’t recommended for anyone with a personal or family history of medullary thyroid carcinoma.
Limitations to keep in mind
Foundayo produces less weight loss than GLP-1 weight-loss injections.
The 11.2% average at the highest dose is clinically meaningful, but it’s lower than injectable Wegovy 2.4 mg (14.9%), injectable Wegovy 7.2 mg (20.7%), and injectable Mounjaro 15 mg (22.5%).
The ATTAIN-1 trial tested doses up to 36 mg in a capsule formulation, but the approved tablet doses go up to 17.2 mg.1
The approved doses produced weight loss ranging from 7.4% to 11.1% in the trial data cited on the Foundayo prescribing label, which is slightly lower than the 36 mg capsule results.
Orforglipron mimics GLP-1 only. It doesn’t mimic GIP, so it’s not a direct oral replacement for Mounjaro’s dual action. People switching from Mounjaro to Foundayo may experience increased hunger levels as their body adapts to the new medication.
The ATTAIN-MAINTAIN trial enrolled a relatively small number of participants (376) and only followed them for 52 weeks after switching.5 Whether the maintenance effect holds over longer periods is still unknown.
No UK regulatory submission has been confirmed. While Lilly has indicated global filings are underway, there’s no timeline for MHRA review.
What this means for the UK
Foundayo is currently only available in the U.S., where it launched on 6 April 2026.
For people in the UK, injectable Mounjaro and injectable Wegovy remain the most effective GLP-1 options currently available.
The Wegovy pill is expected to reach the UK by late 2026 and will likely be the first oral GLP-1 weight-loss option available here.
When Foundayo does receive UK approval, it will offer something the Wegovy pill doesn’t: a GLP-1 tablet with no fasting requirements and no timing restrictions.
For people who find the Wegovy pill’s morning routine impractical, this could be a better fit.
The ATTAIN-MAINTAIN data also open a future treatment pathway: lose weight with injectable Mounjaro or Wegovy with structured lifestyle support, then transition to a daily oral GLP-1 for maintenance.
For a detailed comparison of oral GLP-1 options, including the Wegovy pill and how they compare to injectable Mounjaro, see our guides:
Take home message
Foundayo is the first oral GLP-1 that can be taken without food, water, or timing restrictions.
It produces less weight loss than injectable options, but removes the two main practical barriers that have kept people from starting GLP-1 treatment: needles and strict dosing routines.
The ATTAIN-MAINTAIN data suggest it could also serve as a maintenance option for people who have already lost weight on injectable GLP-1s, though longer-term data are needed.
Foundayo isn’t yet available in the UK. When it does arrive, it will join the Wegovy pill as a second oral option, giving people and prescribers more flexibility in how GLP-1 treatment is delivered.
Whichever medication or format you choose, the evidence consistently shows that combining GLP-1 treatment with structured behaviour change support improves long-term outcomes.
Second Nature’s published research found that members taking semaglutide alongside dietitian-led support achieved an average of 19.1% weight loss at 12 months.7
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
References
- U.S. Food and Drug Administration. (2026). FDA approves first new molecular entity under National Priority Voucher program. Press release, 1 April 2026.
- Wharton, S., et al. (2025). Orforglipron, an oral small-molecule GLP-1 receptor agonist, for obesity treatment. New England Journal of Medicine.
- Eli Lilly. (2025). FDA approves Lilly’s Foundayo (orforglipron), the only GLP-1 pill for weight loss that can be taken any time of day without food or water restrictions. Press release, 1 April 2026.
- Wharton, S., et al. (2025). Oral semaglutide at a dose of 25 mg in adults with overweight or obesity. New England Journal of Medicine, 393(11).
- Eli Lilly. (2025). Lilly’s orforglipron helped people maintain weight loss after switching from injectable incretins to oral GLP-1 therapy. Press release, 18 December 2025.
- Wilding, J.P.H., et al. (2022). Weight regain and cardiometabolic effects after withdrawal of semaglutide. Diabetes, Obesity and Metabolism, 24(8), 1553-1564.
- Richards, R., et al. (2025). A remotely delivered, semaglutide-supported specialist weight management program: 12-month outcomes. JMIR Formative Research, 9(1), e72577.
