Foundayo Weight Loss Results by Dose and Week From the Trials

Foundayo (orforglipron) weight loss results in ATTAIN-1, the 72-week trial behind the tablet, averaged 11.1% on the top 17.2 mg daily dose in adults without diabetes, against 2.1% on placebo, by the US label’s count (Foundayo prescribing information, section 14). That is about 24.4 lb from a 220 lb start (11.1 kg from 100 kg), and the 9 mg and 5.5 mg doses averaged 8.3% and 7.4%. The UK label prints 12.4% for the same dose, counted a different way (UK SmPC, Table 3).

Key facts

• On 17.2 mg, 54.5% lost at least 10% of their weight and 35.9% lost at least 15% by week 72, against 13% and 6% on placebo (US label, Table 6).
• The trial used capsules, and the 17.2 mg tablet matches the 36 mg capsule, 9 mg matches 12 mg and 5.5 mg matches 6 mg (UK SmPC, Table 2).
• The 622 people assigned 17.2 mg who were weighed at week 72 averaged 12.3% lighter (US label, Figure 1).
• The trial’s top-dose group reached its full dose at week 20 (FDA review, Table 16), while the label’s 30-day steps put 17.2 mg on day 151 at the earliest.
• With type 2 diabetes, the ATTAIN-2 trial averaged 9.6% on 17.2 mg against 2.5% on placebo (US label, section 14).
• In its own 64-week trial, the Wegovy pill averaged 13.6% against 2.4% on placebo, in a different population (Wegovy label, Table 11).

How much weight can you lose on Foundayo?

In ATTAIN-1, Foundayo weight loss results rose with the dose, from 7.4% on 5.5 mg to 8.3% on 9 mg and 11.1% on 17.2 mg at week 72, against 2.1% on placebo (US label, Table 6).

The US label’s Table 6 gives the result for each tablet dose, and the UK SmPC, Table 2 names the trial capsule each tablet matches.

The UK label’s 12.4% works out to about 27.3 lb from 220 lb, or 12.4 kg from 100 kg.

On 17.2 mg, 28.5% of people had not lost 5% of their starting weight by week 72, while 18.4% had lost 20% or more (US label, Table 6).

Across both trials, 8% of people on Foundayo stopped it because of side effects, from 6% on 5.5 mg to 10% on 17.2 mg, against 3% on placebo (US label, section 6.1). In the ATTAIN-1 paper, the most common adverse events were gastrointestinal and mostly mild to moderate (ATTAIN-1, NEJM 2025).

Why do Foundayo results say 11.1% in the US and 12.4% in the UK?

The US label’s 11.1% counts all 730 people assigned the top dose in ATTAIN-1, whether or not they kept taking it (US label, Table 6). The UK label’s 12.4% matches the figure a Lilly-funded paper gives for the efficacy estimand, the result if everyone had kept taking the drug as intended (ATTAIN-1 analysis, Obesity Pillars 2026). Four published numbers describe that one group at week 72.

• 11.1% is the US label’s figure. It fills in possibly treatment-related gaps in week-72 weights from people in the same group who stopped treatment but were still weighed (US label, Table 6).
• 11.2% is the orforglipron weight loss result in the NEJM paper, which also uses the treatment-regimen estimand (ATTAIN-1, NEJM 2025).
• 12.3% is the average of the 622 people assigned 17.2 mg who were weighed at week 72, with nothing filled in (US label, Figure 1).
• 12.4% is the UK label’s figure, which matches the efficacy estimand in a Lilly-funded analysis of the trial (ATTAIN-1 analysis, Obesity Pillars 2026).

The FDA disagreed with Lilly’s method for filling in missing weights and used retrieved dropouts multiple imputation, which put the top dose 9.0 points ahead of placebo, the gap the US label prints (FDA review, section 8.1). Lilly’s superiority conclusion "stays the same", the FDA added (FDA review, section 8.1).

The treatment-regimen estimand counts everyone regardless of whether they stopped, while the efficacy estimand "represents the treatment effect under the assumption that all patients adhered to their medication as intended" (indirect comparison, DOM 2026). In ATTAIN-1, 24% of people on 17.2 mg stopped the trial drug (US label, section 14).

The UK SmPC does not name its method, and its placebo figure is 0.9% against 2.1% in the US label (UK SmPC, Table 3). If you keep taking 17.2 mg, 12.4% is the trial estimate that assumes everyone did, and 11.1% also counts people who stopped (ATTAIN-1 analysis, Obesity Pillars 2026).

Why did the Foundayo trial use 36 mg when the top tablet is 17.2 mg?

ATTAIN-1 gave orforglipron as capsules, and Foundayo is a tablet that is absorbed differently, so the same effect comes from fewer milligrams (bioequivalence study, DOM 2026). A Lilly-funded study found the six tablets bioequivalent to the six capsules and explained that "the tablet dose strengths are numerically lower than the capsule dose strengths" (bioequivalence study, DOM 2026).

The UK SmPC pairs each Foundayo tablet with the trial capsule it matches (UK SmPC, Table 2).

• 0.8 mg tablet and 1 mg capsule
• 2.5 mg tablet and 3 mg capsule
• 5.5 mg tablet and 6 mg capsule
• 9 mg tablet and 12 mg capsule
• 14.5 mg tablet and 24 mg capsule
• 17.2 mg tablet and 36 mg capsule

The SmPC warns that the two forms "are not substitutable on a mg-per-mg basis" (UK SmPC, section 5.1). The US label shows the same trial results "as equivalent dosages of once daily FOUNDAYO" (US label, section 14).

The 14.5 mg tablet, the 24 mg capsule in the trial, was only a 4-week step taken in weeks 16 to 20 by the top-dose group, so no trial result exists for staying on 14.5 mg (FDA review, Table 16).

What does Foundayo weight loss look like by week and by month?

The US label’s chart of observed averages shows the three Foundayo dose groups on top of each other through week 12, and each Foundayo curve reaches its lowest plotted point at week 48 (US label, Figure 1). The 5.5 mg group falls behind first, and the 9 mg and 17.2 mg groups stay together through week 16 before they separate. The week-72 averages of 8.1%, 9.4% and 12.3% are slightly smaller losses than at week 48 (US label, Figure 1).

In the data Lilly gave the FDA, every orforglipron group was significantly ahead of placebo "beginning at Week 4 (1-mg dose), the first postbaseline time point assessed, through Week 72" (FDA review).

Everyone started on the 1 mg capsule and moved up one level every 4 weeks until reaching their assigned dose (UK SmPC, section 5.1). In tablet terms, every group took 0.8 mg in weeks 0 to 4, 2.5 mg in weeks 4 to 8 and 5.5 mg in weeks 8 to 12. The top-dose group then took 9 mg in weeks 12 to 16, 14.5 mg in weeks 16 to 20 and 17.2 mg from week 20 to week 72 (FDA review, Table 16).

The FDA treats 52 weeks at the maintenance dose as enough to show that weight loss holds, and the top-dose group had that, from week 20 to week 72 (FDA review). Outside the trial, the label’s steps of at least 30 days, set out in the Foundayo dosage schedule, put 17.2 mg on day 151 at the earliest, against week 20 in the trial (US label, section 2.1).

How much weight can you lose on Foundayo in 3 to 6 months?

The US label’s chart prints values only at week 72, and neither the label nor the ATTAIN-1 abstract gives an average for any earlier week (US label, Figure 1).

Three months into ATTAIN-1, at week 12, every group had just finished 4 weeks at the 5.5 mg level (FDA review, Table 16). On the label’s earliest schedule, 5.5 mg starts on day 61 and 9 mg on day 91, so month 3 is your first month on 5.5 mg.

The 36-week phase 2 trial of orforglipron prints averages at week 26 and week 36. Groups on 12 mg to 45 mg of orforglipron averaged 8.6% to 12.6% at week 26 and 9.4% to 14.7% at week 36, against 2.0% and 2.3% on placebo (phase 2 trial, NEJM 2023). Those are phase 2 doses, and none is a Foundayo tablet strength (UK SmPC, Table 2).

How do Foundayo results compare with the Wegovy pill?

In separate trials, the Wegovy pill (oral semaglutide 25 mg) averaged 13.6% at week 64 in OASIS 4 against 2.4% on placebo (Wegovy label, Table 11), and Foundayo 17.2 mg averaged 11.1% at week 72 in ATTAIN-1 against 2.1% (US label, Table 6). At least 10% and 15% were lost by 59.8% and 47% on the pill, against 54.5% and 35.9% on Foundayo 17.2 mg (Wegovy label, Table 11; US label, Table 6). Both labels count everyone randomized and fill in missing weights from retrieved dropouts (Wegovy label, Table 11; FDA review, section 8.1). Both trials also held the top dose for 52 weeks (Wegovy label, section 14.2; FDA review, Table 16).

OASIS 4 ran 64 weeks with 307 people, 76% of them women and 93% White (Wegovy label, section 14.2). ATTAIN-1 ran 72 weeks with 3,127 people, 64% women, 56% White and 28% Asian (US label, section 14).

Head-to-head evidence on weight loss for the 25 mg Wegovy pill against the top orforglipron dose "is currently lacking" (indirect comparison, DOM 2026). ACHIEVE-3, a direct test against oral semaglutide, enrolled 1,698 adults with type 2 diabetes, used the 7 mg and 14 mg diabetes doses, and measured HbA1c as its main result (ACHIEVE-3, Lancet 2026).

An indirect comparison funded by Novo Nordisk, which makes the Wegovy pill, adjusted for the differences between the trial populations and put the 25 mg pill 3.2 percentage points ahead of the top orforglipron dose (indirect comparison, DOM 2026). A simpler method in the same paper gave 2.3 points, which was not statistically significant.

Foundayo is taken "once daily, with or without food" (US label, section 2.1). The rules for how to take the Wegovy pill are stricter, with the tablet swallowed on an empty stomach in the morning with up to 4 ounces of water and at least 30 minutes before food (Wegovy label, section 2.1). The Wegovy results timeline follows the pill month by month.

How do Foundayo results compare with Wegovy and Zepbound injections?

In adults without diabetes, each weekly injection averaged more weight loss in its own trial than Foundayo did in ATTAIN-1, though these are separate trials, not a head-to-head test. The figures below come from each medicine’s US label (Foundayo, Wegovy, Zepbound).

Placebo groups in these trials lost between 2.1% and 3.9%. With type 2 diabetes, Foundayo 17.2 mg averaged 9.6% at week 72, the same figure Wegovy 2.4 mg reached at week 68, while Zepbound 15 mg averaged 14.7% (US label, section 14; Wegovy label, Table 8; Zepbound label, Table 2).

For a 12-month projection on semaglutide or tirzepatide from your own starting weight, the GLP‑1 weight loss calculator shapes its curve from those trials; it has no Foundayo setting. Tirzepatide results month by month shows the injection’s dose steps beside its weight curve.

How do you compare your own Foundayo results with the trial?

Compare yourself with the trial at the same dose and week. The top-dose group in ATTAIN-1 did not reach 17.2 mg until week 20 (FDA review, Table 16).

Steps above 5.5 mg depend on "treatment response and tolerability", and neither the US label nor the UK SmPC sets a weight-loss target by a given week for stopping (US label, section 2.1).

Your own weight, laid out dose by dose, is what you can hold against the trial path. In Pensday, Foundayo is in the medication list with all six strengths from 0.8 mg to 17.2 mg, and each daily tablet is logged with a reminder. The weight report draws your trend in a different color for each dose step, with one row per dose showing how long you were on it, how far the trend moved and the weekly pace. The report is descriptive and makes no dose suggestions, and dose logging, reminders and weight are in the free tier.