The ATTAIN Trial Data

Foundayo is supported by two Phase 3 trials: ATTAIN-1 for people without diabetes (3,127 participants) and ATTAIN-2 for people with type 2 diabetes (1,613 participants). Both ran for 72 weeks and were randomised, double-blind, placebo-controlled studies.

In ATTAIN-1, three doses of orforglipron were tested against placebo: 6mg, 12mg, and 36mg daily. At the highest dose of 36mg, participants achieved an average weight loss of 12.4% or 27.3 pounds over 72 weeks. All three doses met the primary endpoint of superior weight loss compared to placebo. Cardiometabolic improvements including reductions in blood pressure, triglycerides, and non-HDL cholesterol were observed across all doses.

In ATTAIN-2, orforglipron also demonstrated efficacy in people with type 2 diabetes, with similar dose-dependent weight loss and safety profiles.

The critical additional trial is ATTAIN-MAINTAIN, which studied whether people could switch from injectable GLP-1s — semaglutide (Wegovy) or tirzepatide (Zepbound) — to oral orforglipron. Participants who had completed 72 weeks on an injectable and were then switched to orforglipron maintained their weight loss over a further 52 weeks, confirming that the oral formulation is effective for maintenance after initial injectable therapy.

Foundayo vs Ozempic vs Mounjaro — Direct Comparison

Head-to-head clinical trials comparing oral orforglipron directly to injectable GLP-1s do not exist. However, comparing the results from their respective Phase 3 trials gives a realistic picture of relative efficacy.

The data shows that orforglipron at 12.4% weight loss falls between semaglutide (14.9%) and what would be a lower tirzepatide dose, but direct comparison is complicated by different patient populations and trial designs. However, the ATTAIN-MAINTAIN trial’s demonstration that people can switch from injectables to orforglipron and maintain their weight loss suggests the formulations are functionally equivalent for maintenance purposes.

The key advantage: no restrictions

Foundayo can be taken at any time of day without restrictions on food or water intake. This is a genuine convenience advantage over some other oral formulations that have strict timing and food requirements. Weekly injections also have timing considerations around when to inject. For someone who values daily oral simplicity, Foundayo removes the injection burden entirely.

The efficacy trade-off

Orforglipron produces slightly lower average weight loss than the highest doses of tirzepatide (20.9% vs 12.4%) but comparable or slightly higher loss than semaglutide (14.9% vs 12.4%). Individual response varies significantly with all GLP-1 medications — some people respond better to one class than another. The difference between 12% and 21% weight loss is meaningful at the population level but may be less important than finding the medication that works best for your individual response and side effect tolerance.

Can You Switch From Ozempic or Mounjaro to Oral GLP-1?

Yes. The ATTAIN-MAINTAIN trial specifically studied this transition. Participants who had completed 72 weeks on either Wegovy (semaglutide) or Zepbound (tirzepatide) were switched to oral orforglipron and maintained their weight loss over 52 weeks.

However, switching is not as simple as taking a tablet instead of injecting. The dose equivalence is not one-to-one and your clinician will need to determine the appropriate starting dose of orforglipron based on your prior response to the injectable. The typical approach would be to transition from the injectable at the dose you have been stable on to an intermediate dose of orforglipron (likely 12mg) and then adjust based on your response and side effects.

The reasons to consider switching would be needle phobia, inconvenience with weekly injections, desire to simplify medication management, or preference for oral medications. The reasons to stay on injectables would be greater weight loss with the injectable formulation (particularly tirzepatide) or better side effect tolerability on the injectable you are already using.

Who Benefits Most From Oral GLP-1?

Oral orforglipron is worth considering if you have needle phobia or injection anxiety that has prevented you from starting injectable GLP-1 therapy. For many people, oral medication is psychologically easier to take consistently than weekly injections, even if the efficacy is slightly lower.

Oral GLP-1 is also worth considering if you are already on an injectable and experiencing needle site reactions, injection-related pain, or simply prefer the simplicity of a daily pill. The ATTAIN-MAINTAIN data shows you can make the switch without losing the weight loss benefits.

Oral GLP-1 is less optimal if you are a strong responder to tirzepatide — the 20.9% weight loss from Mounjaro/Zepbound is substantially higher than the 12.4% from orforglipron, and switching down would likely result in some weight regain.

Cost considerations matter too. Orforglipron’s pricing has not yet been fully established in the market as of June 2026, but it is expected to be comparable to injectable GLP-1s. Insurance coverage will vary.

Frequently Asked Questions