Foundayo Weight Loss Results

How much weight can you lose on Foundayo?

Adults on the highest approved Foundayo dose lost around 11% of body weight on average over 72 weeks. The figure comes from the ATTAIN-1 clinical trial. The trial enrolled over 3000 adults who were obese. None suffered from type 2 diabetes.

What is Foundayo? Foundayo (orforglipron) is a once-daily oral GLP-1 (glucagon-like peptide-1) receptor agonist. Eli Lilly makes both Foundayo and injectable Mounjaro. 

The US Food and Drug Administration (FDA) approved Foundayo in April 2026. The approval covers adults with obesity or adults with overweight who have at least one weight-related medical problem.

Higher Foundayo doses produced more weight loss in the ATTAIN-1 trial. Orforglipron weight loss averaged around 7.5% at the lowest tested dose. Adults on the highest dose lost about 11%. 

The placebo treatment group (those given an inactive pill for comparison purposes) lost around 2%. This gives a rough sense of what dietary changes and increased physical activity might achieve on their own.

Individual Foundayo results were varied. Some people in the trial lost a lot of weight. More than half of adults on the highest Foundayo dose lost at least 10% of their starting weight, and about a third reached 15% or more. 

A smaller group, close to one in five, lost over 20%. Wide variation like this can be common in obesity trials, with a number of possible factors.

People with type 2 diabetes still lost weight on Foundayo, although the average drop was smaller. In the ATTAIN-2 trial, patients with type 2 diabetes lost around 9.6% of body weight on the highest dose. The trial ran for 72 weeks. 

The gap between diabetic and non-diabetic groups is typical for GLP-1 weight loss medications. Results across both trials show meaningful weight loss for most adults who stay on treatment. Dose is the biggest factor, but time on treatment matters too.

How long does it take to see results?

Most people do not see dramatic weight loss in the first few weeks of Foundayo. Appetite changes usually come first, sometimes within the first month. The timeline to seeing visible weight and inch loss often takes a few months. 

During the first few months, we would strongly encourage you to focus on making healthy, sustainable changes to your diet, as well as trying to increase the amount of movement in your day. This can help support your weight loss while also improving your overall health and wellbeing.

Weight loss in the ATTAIN-1 trial built up steadily over the first year, then plateaued . Most of the reduction came within the first 48 weeks. After that, the medication helps you maintain your new weight.

Foundayo’s starting dose is 0.8 mg once a day. From there, you stay on each strength for at least 30 days before stepping up through 2.5 mg, 5.5 mg, 9 mg, 14.5 mg, and 17.2 mg. The step-up schedule is slow for a reason. Side effects are much more common when doses rise too quickly. 

Getting to the final maintenance dose usually takes around five months. You do not have to reach 17.2 mg. The 9 mg and 14.5 mg strengths are also maintenance doses. Staying at either one is fine if you are seeing results and feel well.

The gentle step-up frustrates some people, especially during the first two or three dose increases. Some adults see steady weight loss from the first month. Others find the scale shifts little at starter doses and only moves as the dose climbs. Both of these response patterns are completely normal.

What factors affect results?

Dosage is the biggest factor. The Foundayo trial results show higher doses produce more weight loss. Average weight loss at the 17.2 mg maximum strength was noticeably larger than at the lowest tested dose.

Consistency comes next. Missing doses regularly will reduce results. Adults who stayed on Foundayo for the full 72 weeks in ATTAIN-1 lost more weight on average than those who stopped early. 

Foundayo should always be used alongside an improved diet and increased physical activity, not as a replacement. The placebo group in ATTAIN-1 lost about 2% of body weight from lifestyle support alone.

Two people on the same dose can lose markedly different amounts of weight. Foundayo’s efficacy varies more than the averages suggest. Starting BMI is part of it. People with a higher BMI tend to lose more weight in actual kilograms, even when the percentage loss is similar. 

Type 2 diabetes lowers the average response, as ATTAIN-2 showed. In the Foundayo clinical trials, a small group of people lost little weight, even on the highest dose. 

Why some people respond so weakly is not fully understood. Individual differences in biology may play a role. If weight loss stalls, a dose adjustment or extra support may help.

How do results compare to other GLP-1 weight loss medications?

Foundayo’s average weight loss falls below injectable Wegovy and Mounjaro. Injectable Wegovy (semaglutide 2.4 mg) produced an average 15% weight loss over 68 weeks in its STEP-1 trial. 

Mounjaro (tirzepatide 15mg) reached up to around 21% over 72 weeks in the SURMOUNT-1 trial. At the highest dose, Foundayo’s average weight loss was roughly 11%. Without a trial that put all three drugs side by side, the percentages give only a rough comparison.

The one head-to-head comparison so far is the ACHIEVE-3 trial. It tested Foundayo against Rybelsus, oral semaglutide at the doses used for type 2 diabetes, over 52 weeks. Foundayo lowered blood sugar more than Rybelsus at matched doses. 

Weight loss was not the main thing the trial measured, but the numbers favoured Foundayo too – around 9% body weight reduction at the top dose, compared with around 5% on the top Rybelsus dose used in the trial. The trial did not include the higher-dose oral semaglutide approved for weight loss. 

That comparison has not been done. And no trial yet compares Foundayo against injectable Wegovy or Mounjaro.

Convenience is where Foundayo earns its place. You can take the small molecule, non-peptide pill at any time of day, with no food or water restrictions. Injectable Wegovy and Mounjaro are weekly injections and injectable liraglutide is daily. The oral form of Wegovy, made by Novo Nordisk, is a once-daily pill. 

You take it on an empty stomach, with strict water and fasting rules. Side effects look broadly similar across these GLP-1 weight loss medications. Tablets remove the issue of injection site reactions. 

For some people, an easy routine and avoiding injections matter more than maximising weight loss. For others, the strongest result wins.

When should I see a doctor?

In the ATTAIN-1 trial, between roughly 5% and 10% of adults stopped Foundayo due to adverse events. Most were stomach-related, like nausea and diarrhoea. But the majority managed to continue with treatment, and reported stomach-related  symptoms to be mild or moderate.

Speak to our clinical team for support with:

• Persistent nausea or mild vomiting that does not stop you from being able to eat or drink.
• Mild diarrhoea or constipation.
• Indigestion or reflux.
• Questions about whether to step up, stay on, or pause your dose because of side effects.

Contact your GP or call NHS 111 if you notice any of the following:

• Vomiting that stops you from keeping fluids down
• A lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath, which may signal a rare thyroid tumour.
• Yellowing of skin or eyes, or severe pain in the upper right side of your stomach, which may signal a gallbladder problem.
• Symptoms of low blood sugar if you also take insulin or another type 2 diabetes medication.
• Any changes to your vision

Stop Foundayo and call 999 or go to A&E if you notice any of the following:

• Signs of a severe allergic reaction, including swelling of the face, lips, tongue, or throat, rash, or difficulty breathing.
• Severe stomach pain that spreads to the back may signal pancreatitis (inflammation of the pancreas).
• Signs of severe dehydration: dark urine, dizziness, confusion or feeling faint.

You should not take Foundayo if you or a close family member has had medullary thyroid cancer. You should also not take Foundayo if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). MEN 2 is a rare inherited condition that raises the risk of certain tumours.

Frequently asked questions

Does Foundayo work?

Yes, for most adults. In the ATTAIN-1 trial, more than half of adults on the highest dose lost at least 10% of their starting weight over 72 weeks. Around one in five lost over 20%. A small number of people in the Foundayo clinical trials saw little weight loss, even on the highest dose.

How effective is Foundayo?

Orforglipron results from ATTAIN-1 show average weight loss of around 11% of body weight at the highest dose over 72 weeks. That sits below injectable Wegovy (around 15% at 2.4mg) and Mounjaro (up to around 21%). Foundayo’s effectiveness and how much you lose depends on the dose and how long you stay on treatment, alongside increased movement and healthier diet.

What happens if I stop taking Foundayo?

Most people regain some weight after stopping GLP-1 weight loss medications. A 2026 BMJ review found that adults who stopped semaglutide or tirzepatide were estimated to regain about 10 kg on average within the first year after stopping. 

Data on stopping Foundayo specifically is limited because the medication is new. The pattern seen with similar drugs is for appetite to return within weeks of stopping. Weight regain typically follows in the months after. Speak to our clinical team before stopping if you are considering it.

Key takeaways

• Adults on the highest dose of Foundayo lost around 11% of body weight on average over 72 weeks in ATTAIN-1. Adults with type 2 diabetes lost around 9.6% on the highest dose in ATTAIN-2.
• More than half of adults on the highest dose lost at least 10% of their starting weight, and roughly one in five lost over 20%.
• Most of the weight loss happens in the first year of treatment. After the first year, weight loss often slows down and becomes more steady, rather than continuing to drop at the same pace. 
• Foundayo’s success rate depends on dose, how consistently you take it, dietary changes, increased physical activity, starting weight, and individual biological response.
• Average weight loss is lower than injectable Wegovy (around 15% at 2.4mg) and Mounjaro (up to around 21%). For many patients, the main advantage is convenience: a once-daily pill with no food or water restrictions.

References

Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment, New England Journal of Medicine, 2025 [Accessed 14 May 2026].

Orforglipron, an oral small-molecule GLP-1 receptor agonist, for the treatment of obesity in people with type 2 diabetes (ATTAIN-2): a phase 3, double-blind, randomised, multicentre, placebo-controlled trial, The Lancet, 2026 [Accessed 14 May 2026].

Efficacy and safety of once-daily oral orforglipron compared with oral semaglutide in adults with type 2 diabetes (ACHIEVE-3): a multinational, multicentre, non-inferiority, open-label, randomised, phase 3 trial, The Lancet, 2026 [Accessed 14 May 2026].

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, Eli Lilly and Company, 2026 [Accessed 14 May 2026].

Foundayo (orforglipron) Prescribing Information, U.S. Food and Drug Administration, 2026 [Accessed 14 May 2026].

Once-Weekly Semaglutide in Adults with Overweight or Obesity, New England Journal of Medicine, 2021 [Accessed 14 May 2026].

Tirzepatide Once Weekly for the Treatment of Obesity, New England Journal of Medicine, 2022 [Accessed 14 May 2026].

Semaglutide for managing overweight and obesity: NICE technology appraisal guidance TA875, National Institute for Health and Care Excellence, 2023 [Accessed 14 May 2026].

Weight regain after cessation of medication for weight management: systematic review and meta-analysis, The BMJ, 2026 [Accessed 14 May 2026]. 

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