Foundayo for maintenance: Dosing, plateaus and weight loss results

Foundayo authorisation for weight maintenance in the UK

Indeed it is. The MHRA authorised orforglipron, sold as Foundayo, on 10 August 2026 for weight loss and weight maintenance alongside a reduced-calorie diet and increased physical activity. For weight management, the authorisation covers adults with a BMI of 30kg/m² or above, or a BMI from 27kg/m² to below 30kg/m² with at least one weight-related comorbidity. [1]

That matters because ‘maintenance’ is not an off-label interpretation of the medicine’s purpose. It is part of the authorised UK use.

It does not, however, mean that everyone who has reached a lower weight should automatically move to Foundayo. Weight maintenance can involve continuing the same treatment, changing treatment, or using another clinically appropriate plan. The evidence for Foundayo after injectable treatment answers one part of that decision, not all of it.

What does ‘weight maintenance’ mean with Foundayo?

In this context, weight maintenance means trying to preserve weight reduction that has already been achieved. It does not necessarily mean keeping body weight completely unchanged, and it does not mean that treatment has failed if a small amount of weight is regained.

ATTAIN-MAINTAIN measured how much of the weight reduction achieved during the preceding SURMOUNT-5 trial was still present after another 52 weeks. This is why figures such as 74.7% and 79.3% should not be read as new percentages of body weight lost on Foundayo. They describe the proportion of earlier weight reduction that was maintained. [2]

The distinction is important for people considering Foundayo maintenance after Zepbound, Mounjaro or Wegovy. The relevant question is not simply ‘will I keep losing weight?’ It is ‘how much of the reduction I have already achieved might be preserved if my treatment changes?’

Foundayo maintenance dosing

There is no single Foundayo maintenance dose that is appropriate for everyone. The MHRA’s UK authorisation announcement states that treatment starts at 0.8mg once daily and is escalated through 2.5mg, 5.5mg, 9mg, 14.5mg and 17.2mg, with a minimum of one month at each dose level. [1]

The important point is that ‘maintenance dose’ does not mean there is one fixed tablet strength for everyone who is maintaining weight. Foundayo dosing selection depends on the authorised UK product information, treatment response, tolerability and individual clinical circumstances.

Important: Foundayo was authorised in the UK on 10 August 2026. The MHRA said the UK Summary of Product Characteristics and Patient Information Leaflet would be published on the MHRA Products website within seven days of approval. As of 13 August 2026, those documents were not yet available there, so the MHRA authorisation notice is the UK source used here for the published dose-escalation sequence. [1]

ATTAIN-MAINTAIN trial study results

ATTAIN-MAINTAIN was a phase 3b, randomised, double-blind, placebo-controlled trial conducted at 29 sites in the United States. It enrolled 376 adults who had completed 72 weeks of treatment in SURMOUNT-5. One cohort had previously received tirzepatide and the other injectable semaglutide. [2]

The tirzepatide cohort included 205 participants and the semaglutide cohort 171. Eligible participants had lost at least 5% of their body weight during SURMOUNT-5 and did not have diabetes. [2]

The primary analysis focused on participants whose weight had reached a plateau near the end of the preceding trial. Plateau was defined as less than 5% body-weight change between weeks 60 and 72 of SURMOUNT-5. [2]

Participants then received once-daily orforglipron or placebo for a further 52 weeks. The study asked how much of the earlier weight reduction was maintained.

Weight loss maintenance results with Foundayo

Among participants who had reached a weight plateau before entering ATTAIN-MAINTAIN, orforglipron preserved substantially more of the previous weight reduction than placebo. [2]

The trial also looked at a higher threshold: maintaining at least 80% of the previous weight reduction. In the tirzepatide cohort, 43.7% of plateau participants taking orforglipron achieved this, compared with 16.4% on placebo. In the semaglutide cohort, the figures were 55.0% and 6.9%, respectively. [2]

These are group averages from a defined trial population. They cannot predict exactly how much weight an individual person will maintain.

Switching from Zepbound to Foundayo for maintenance

Zepbound is the US brand name for tirzepatide used for chronic weight management. In the UK, tirzepatide is authorised for weight management under the brand name Mounjaro. [3][4]

ATTAIN-MAINTAIN therefore provides evidence relevant to people considering Zepbound-to-Foundayo maintenance, even though UK prescribing uses Mounjaro rather than Zepbound.

Participants in the tirzepatide cohort had previously completed 72 weeks of tirzepatide at a maximum tolerated dose of 10mg or 15mg once weekly. They had lost an average of 21.5% of their original SURMOUNT-5 body weight by the time they entered ATTAIN-MAINTAIN. After a further 52 weeks on orforglipron, average body weight remained 16.8% below the original baseline in a sensitivity analysis. This represented average regain of roughly 5kg from the point of transition while preserving most of the earlier weight reduction. [2]

That is useful evidence, but it is not evidence that everybody moving from tirzepatide to Foundayo should expect the same result.

Trial use dose used after tirzepatide

This is where trial evidence and prescribing instructions need to be kept separate. ATTAIN-MAINTAIN used an investigational capsule formulation of orforglipron. Participants randomised to active treatment started at 12mg of that capsule formulation, which the paper states is equivalent to the marketed 9mg tablet dose.

The first dose was intended to be taken within 14 days of the last SURMOUNT-5 injection, and participants then increased every four weeks until reaching the study target or their maximum tolerated dose. [2]

Foundayo maintenance weight regain after switching to Zepbound

This is not the case. The trial was designed to assess preservation of previous weight reduction, not to require every participant to remain at exactly the same weight.

People moving from tirzepatide to orforglipron regained some weight on average, but they still retained most of their previous reduction and maintained substantially more than the placebo group. [2]

The trial authors proposed one possible explanation for the difference between the tirzepatide and semaglutide cohorts: tirzepatide acts at both GIP and GLP-1 receptors, whereas orforglipron acts at the GLP-1 receptor. They described this as a hypothesis that requires further investigation, not a proven explanation for an individual person’s response. [2]

So a small amount of regain after changing treatment should not automatically be interpreted as ‘Foundayo not working’. The clinical question is whether the person is maintaining a meaningful proportion of previous weight reduction, how their health markers and appetite are changing, whether treatment is tolerable, and whether the overall plan remains appropriate.

What happened after moving from injectable Wegovy to Foundayo?

The semaglutide cohort showed stronger preservation of previous weight reduction on average.

Participants assigned to orforglipron had been 16.5% below their original SURMOUNT-5 baseline when ATTAIN-MAINTAIN began. After 52 weeks, average body weight remained 15.1% below that original baseline in the sensitivity analysis — an average difference of around 1kg from the point of transition. [2]

Among plateau participants, 79.3% of the previous weight reduction was maintained with orforglipron, compared with 37.6% with placebo. [2]

This evidence relates to injectable semaglutide. It should not be presented as direct evidence for a move from the newer oral Wegovy tablet to Foundayo because that route was not studied in ATTAIN-MAINTAIN.

Foundayo vs Zepbound for maintenance: which is better?

ATTAIN-MAINTAIN cannot answer that directly. The trial compared moving to orforglipron with moving to placebo after previous tirzepatide or semaglutide treatment. It did not include a group that simply stayed on its existing injectable medicine. [2]

That means the study can support this conclusion:

In this trial population, moving to orforglipron maintained more previous weight reduction than stopping active treatment and receiving placebo.

It cannot support this conclusion:

Foundayo is as effective as, better than or worse than continuing Zepbound or Mounjaro for maintenance.

Those are different questions. A person deciding whether to continue tirzepatide or move to Foundayo needs an individual comparison of expected weight control, side effects, treatment preferences, medical history and the practicalities of long-term treatment.

Why the ATTAIN-MAINTAIN results need careful interpretation

The study provides unusually direct evidence about oral maintenance treatment after substantial weight loss, but several limitations matter.

First, participants had already completed 72 weeks in another obesity trial. This was not a group starting weight-management treatment for the first time. [2]

Second, all study sites were in the United States, and the study population was predominantly white. [2]

Third, placebo participants who regained at least 50% of the weight they had previously lost could receive rescue orforglipron from week 24. By week 52, only 25 placebo participants in the tirzepatide cohort and 12 in the semaglutide cohort had remained on placebo without another active weight-management intervention. This makes the later placebo comparison more complex. [2]

Fourth, the maintenance period lasted 52 weeks. The study therefore provides one year of evidence after the transition, not indefinite evidence about long-term maintenance. [2]

Finally, the investigators noted that there is no single widely agreed definition or calculation for ‘maintenance of weight reduction’. They reported several endpoints and sensitivity analyses for that reason. [2]

What should be considered before using Foundayo for maintenance?

A maintenance decision is not only about the number on the scales or the tablet strength.

A prescriber may need to consider:

• which medicine you are currently taking and the dose you have reached
• how much weight you have lost and whether your weight has stabilised
• whether your aim is to maintain the current reduction or continue losing weight
• side effects and how well the current treatment is tolerated
• other medicines and health conditions
• whether the evidence from ATTAIN-MAINTAIN resembles your circumstances
• the current UK Foundayo product information and any reasons a switch may not be suitable

The right maintenance plan can therefore differ between people who have reached a similar weight.

Foundayo is authorised in the UK for weight maintenance in eligible adults, and ATTAIN-MAINTAIN provides direct evidence that orforglipron can preserve a substantial proportion of weight previously lost with injectable tirzepatide or semaglutide. [1][2]

The strongest evidence is not that a Foundayo pill will keep every kilogram off, or that it is equivalent to staying on Zepbound, Mounjaro or Wegovy. It is that people who switched to orforglipron maintained substantially more of their earlier weight reduction than people randomised to placebo over the following 52 weeks. [2]

There is also no universal Foundayo maintenance dose or safe do-it-yourself conversion from an injectable treatment. Dose and treatment-change decisions need to follow current UK product information and prescriber review.