Not Losing Weight on Foundayo: Why and What to Do

How much weight can I lose with Foundayo?

In the ATTAIN-1 clinical trial, the highest dose of Foundayo produced average weight loss of 11.2% of body weight over 72 weeks. For someone starting at 100kg, 11.2% works out at roughly 11kg. Adults in the placebo treatment group, given an inactive pill for comparison, 2.1% over the same 17 months. Foundayo’s weight loss results have been recorded in several clinical trails.

The ATTAIN-1 trial enrolled 3,127 adults with obesity or overweight plus a weight-related condition. Just over half of the people on the top dose lost at least 10% of their starting weight. Around a third reached 15% or more, and close to one in five lost 20% or more. 

Everyone else lost under 10%, and a minority lost almost nothing at all. Two people can take the same daily pill, at the same dose, for the same length of time, and finish in completely different places.

All four figures below come from ATTAIN-1, counting every participant whether or not they stayed on treatment. 

Foundayo dose in ATTAIN-1	Average weight change at 72 weeks
6mg	7.5% loss
12mg	8.4% loss
36mg	11.2% loss
Placebo	2.1% loss

The numbers on your Foundayo tablet box will not match the numbers in the headlines. ATTAIN-1 used capsules at 6mg, 12mg and 36mg. However, Foundayo is manufactured in tablet form. The lowest dose is 0.8mg, increasing to a maximum of 17.2mg. Foundayo tablets and capsules are not bioequivalent, meaning they don’t deliver the same amount of medicine into the body in the same way, so the available strengths differ between the two formulations. 

The UK Foundayo prescribing information describes the 36mg orforglipron capsule as equal in effect to the 17.2mg tablet. Foundayo weight loss results also build slowly, and the 11.2% trial figure reflects 17 months of consistent treatment.

Why am I not losing weight on Foundayo?

Dose and time on treatment are the first two things to check. Four other things can hold your weight steady, and each one needs a different approach:

• skipping or forgetting doses
• a shift in your eating habits
• an undiagnosed or untreated health condition
• taking a medicine that interacts with Foundayo

Have you reached the highest dose of Foundayo yet?

0.8mg is a starting dose used to build tolerance, and it is not the maintenance dose that produced the trial figures. The Medicines and Healthcare products Regulatory Agency (MHRA) licensed the tablet in August 2026. The licensed doses run 0.8mg, 2.5mg, 5.5mg, 9mg and 14.5mg, up to a maximum of 17.2mg. Each dose runs for at least 30 days before the next increase. That gradual increase is there to help your body adjust to the medicine.

It takes at least five months to reach the highest 17.2mg dose. The journey is often slower if you are seeing good results at lower doses, or are experiencing side effects.

If you have sat at the lowest 0.8mg dose or at 2.5mg for several months, you have not yet reached your Foundayo maintenance dose. The higher doses of Foundayo are the ones that produced the headline weight loss figures.

Has Foundayo had enough time to work?

Foundayo’s 11.2% figure comes from 72 weeks of treatment, which is roughly 17 months. Most people spend their first five months climbing the dose ladder. 

Seeing nothing on the scales in the first two months doesn’t tell you much, because you have not reached the dose the trial measured. We would encourage anyone judging their results at that point to give it longer. The trial evidence has almost nothing to say about progress by week eight.

Are you taking Foundayo the same way every day?

Taking Foundayo daily is what holds a steady level of the medicine in your blood. That level builds over roughly a week of daily dosing. If you forget a dose, the prescribing information says to take it as soon as you can. Never double up the following day. 

With Foundayo, no weight loss is not tied to when you take your daily dose. Foundayo does not need an empty stomach. You can take it at any time of day, with or without food, and with no restriction on water. Make sure to swallow the tablet whole instead of crushing or chewing it.

Has what you eat drifted without you noticing?

Weight loss medication reduces hunger, but might not influence what you eat when hunger returns. In our experience, appetite suppression feels strongest in the weeks just after a dose increase, then settles into something milder. Portions often creep back up subconsciously, and snacks reappear.

Body composition is the other half of this. Weight loss generally takes some muscle alongside fat. Your body uses energy to maintain muscle tissue, even when you are resting. A lighter body already burns less energy than a heavier one did. Losing muscle pushes that number down further. It means eating exactly as you did before does less for you than it used to.

Foundayo is licensed for use alongside healthy dietary changes and increased physical activity. The ATTAIN-1 participants were doing both throughout the trial. Current guidance for people on GLP-1 treatment is to keep protein up across meals and add structured resistance work alongside regular physical activity. Both are worth starting while you are still climbing the dose ladder.

Could another condition or medicine be affecting my Foundayo weight loss?

Some conditions and medicines slow weight loss, whatever the medication is doing. The NHS lists weight gain among the symptoms of an underactive thyroid, alongside tiredness and increased sensitivity to cold. The World Health Organization links polyendocrine metabolic ovarian syndrome (PMOS) with insulin resistance, type 2 diabetes and obesity.

ATTAIN-2 studied orforglipron in people with type 2 diabetes. It reported 9.6% average weight loss at the top dose over 72 weeks. This compares to 11.2% in the diabetes-free ATTAIN-1 population. Those were separate trials with different participants, so the gap does not prove diabetes was the cause.

Prescribed medicines are worth checking as well. Some medications speed up how quickly your liver breaks Foundayo down, which leaves less of it circulating in your system. The prescribing information calls these CYP3A4 inducers.

We will not prescribe Foundayo alongside a strong inducer. The ones most likely to affect you include:

• carbamazepine for epilepsy
• rifampicin for tuberculosis
• the herbal remedy St John’s wort

You can take Foundayo with a moderate inducer, but we will monitor you more closely and may need to increase your dose.

Never stop or change a medicine on your own to make Foundayo work better. Bring your full medicine list to any review so we can check for interactions and give you the correct advice.

What is a Foundayo weight loss plateau?

A Foundayo plateau can be a normal stage of weight loss. It does not mean the medicine has stopped working. Your energy needs fall as your weight falls. Part of that is simple maths, because a smaller body costs less to run. 

Studies showing this effect suggest the drop goes further than your smaller size can explain. Your body also becomes more efficient, using less fuel to do the same work. Eating as you did at 100kg may no longer produce losses. At 88kg, the same eating pattern may only hold you level.

Four checks are worth running before you decide that Foundayo is no longer working:

• Dose headroom: whatever gap remains between your current dose and 17.2mg, or the maximum dose you can tolerate
• Food intake: portions, snacks and drinks compared with three months ago
• Muscle: any resistance work at all across a typical week, which helps protect the muscle that keeps your energy use up 
• Timescale: how long the reading on your scales has genuinely not moved. A few weeks of no movement is common

What are the alternatives to Foundayo?

Published trial averages for some licensed injections run higher than the ATTAIN-1 average for orforglipron. Foundayo sits at the lower end of the licensed options, and the weekly injections sit at the upper end.

Medicine and dose	Average weight loss	Trial
Mounjaro (tirzepatide) 15mg	20.9% over 72 weeks	SURMOUNT-1
Wegovy injection 7.2mg	18.7% over 72 weeks	STEP UP
Wegovy injection 2.4mg	14.9% over 68 weeks	STEP 1
Wegovy pill 25mg	13.6% over 64 weeks	OASIS 4
Foundayo 17.2mg	11.2% over 72 weeks	ATTAIN-1

None of those trials compared their medicine directly against Foundayo. Different trials recruit different people, so treat those figures as a rough guide.

Switching also carries no guarantee of a better outcome. People respond differently to GLP-1 medicines, and nobody yet knows why. Someone who loses little on one may lose little on the next.

Mounjaro acts on two gut hormone receptors, while orforglipron acts on one. In SURMOUNT-5, the only head-to-head trial of the two, Mounjaro produced 20.2% average weight loss against 13.7% for Wegovy at 2.4mg. If you are looking to explore a switch, discuss it with us. 

When should I see a doctor?

Foundayo is not suitable for everyone. The UK prescribing information lists one reason not to take it: a known allergy to orforglipron or to anything else in the tablet. The US label also rules it out for anyone with a personal or family history of medullary thyroid carcinoma (MTC). The same applies to multiple endocrine neoplasia syndrome type 2. Tell us about any family history of thyroid cancer before you start.

Some symptoms below need urgent care whether or not Foundayo caused them.

Contact our clinical team for mild side effects and dose questions:

• Persistent mild nausea, vomiting, diarrhoea or constipation that you can still manage
• Reflux, heartburn, wind or changes in appetite
• Questions about whether to step up or hold your current dose

Contact your GP or call NHS 111 the same day if you notice:

• A lump or swelling in your neck, a hoarse voice, or trouble swallowing
• Yellowing of the skin or eyes, or severe pain in the upper right of your abdomen
• Vomiting or diarrhoea so persistent that you cannot keep fluids down
• Changes to your vision, particularly if you have diabetic eye disease
• Shakiness, sweating or confusion if you also take insulin or a sulfonylurea

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

• Severe abdominal pain that spreads through to your back
• Swelling of the face, lips or throat, or any trouble breathing
• Signs of severe dehydration, such as passing unusually little urine or feeling faint
• Thoughts of harming yourself, in which case go to A&E and ask for the CRISIS team. If you are not in immediate danger, call 111 and select the mental health option

Common questions about Foundayo not working

Has Foundayo stopped working?

A plateau does not mean that orforglipron is not working, but both can look identical on the scales. Appetite is the more useful signal. If your hunger levels are still lower than before you started, the medicine is likely still acting even though the weight is staying put. If your appetite has returned to where it was, tell us, because that is worth reviewing properly.

Is Foundayo less effective than the injections?

On published trial averages, the injections come out higher. Whether Foundayo is less effective for you specifically is a different question. Some people lose 20% or more on Foundayo, and some lose far less on Mounjaro. Trial averages describe groups rather than the individuals inside them.

Is Foundayo available on the NHS?

Foundayo is not currently available on the NHS. The National Institute for Health and Care Excellence (NICE) is reviewing orforglipron for NHS use. It expects to publish a decision in late 2026.

Key takeaways

• Average weight loss on the highest dose reached 11.2% over 72 weeks in ATTAIN-1
• Just over half of that group lost 10% or more, and close to one in five lost 20% or more
• If you have not yet reached your maintenance dose, slow progress is too early to call a failure
• A plateau is a normal stage in a weight loss journey
• The bottom line: check dose and time on treatment first, then adherence, eating patterns, medical conditions and medicines

References

Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment (ATTAIN-1), New England Journal of Medicine, 2025 [Accessed 17 August 2026].

Orforglipron, an oral small-molecule GLP-1 receptor agonist, for the treatment of obesity in people with type 2 diabetes (ATTAIN-2), The Lancet, 2025 [Accessed 17 August 2026].

UK first in Europe to authorise orforglipron for weight management and type 2 diabetes, GOV.UK, 2026 [Accessed 17 August 2026].

Foundayo 17.2 mg film-coated tablets, Summary of Product Characteristics, electronic medicines compendium, 2026 [Accessed 17 August 2026].

Foundayo (orforglipron) tablets: prescribing information, Eli Lilly and Company, 2026 [Accessed 17 August 2026].

Adaptive thermogenesis in humans, International Journal of Obesity, 2010 [Accessed 17 August 2026].

Underactive thyroid (hypothyroidism), NHS, 2026 [Accessed 17 August 2026].

Where to get urgent help for mental health, NHS, 2026 [Accessed 17 August 2026].

Polycystic ovary syndrome, World Health Organization, 2026 [Accessed 17 August 2026].

Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), New England Journal of Medicine, 2022 [Accessed 17 August 2026].

Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5), New England Journal of Medicine, 2025 [Accessed 17 August 2026].

Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1), New England Journal of Medicine, 2021 [Accessed 17 August 2026].

Once-weekly semaglutide 7·2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial, The Lancet Diabetes & Endocrinology, 2025 [Accessed 17 August 2026].

Single-dose 7.2mg semaglutide (Wegovy) pen approved to treat adult patients with obesity, GOV.UK, 2026 [Accessed 17 August 2026].

Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity (OASIS 4), New England Journal of Medicine, 2025 [Accessed 17 August 2026].

Orforglipron for managing overweight and obesity [ID6516], NICE, 2026 [Accessed 17 August 2026].

Optimizing GLP-1 therapies for obesity and diabetes management, Obesity Pillars, 2025 [Accessed 17 August 2026]. 

GLP-1 agonists and changes in body mass and composition in adults with overweight or obesity with or without type 2 diabetes mellitus: a systematic review and meta-analysis, International Journal of Obesity, 2026 [Accessed 17 August 2026]. 

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