Compound Profile — Last checked June 4, 2026

Foundayo (Orforglipron) — Oral Non-Peptide GLP-1 Profile

Q: What is orforglipron?

Orforglipron (LY3502970) is Eli Lilly's once-daily oral non-peptide GLP-1 receptor agonist. Unlike semaglutide or tirzepatide, which are peptide drugs requiring injection or special absorption chemistry, orforglipron is a small-molecule GLP-1 agonist that can be taken as a conventional oral tablet without food or timing restrictions. It received FDA approval under the brand name Foundayo on April 1, 2026 for chronic weight management in adults with obesity, or overweight with at least one weight-related comorbidity.

Q: Is orforglipron approved?

Yes. Orforglipron received FDA approval under the brand name Foundayo on April 1, 2026 for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity. It is the first non-peptide oral GLP-1 receptor agonist to reach market. Approval was issued under the Commissioner's National Priority Voucher pilot programme 50 days after filing. The ACHIEVE programme supports a separate type 2 diabetes filing path. For the latest regulatory status, see our approval tracker.

Q: How much weight loss does orforglipron produce?

In ATTAIN-1, the pivotal Phase 3 obesity trial, orforglipron at the highest tested dose (36 mg) produced approximately 14.3% mean weight loss at 72 weeks. The FDA-approved Foundayo label caps maintenance dosing at 17.2 mg, with approximately 12.4% mean weight loss at 72 weeks at that approved dose. Both ranges land in the same band as injectable semaglutide 2.4 mg in STEP 1 (~14.9% at 68 weeks), making orforglipron the first oral GLP-1 agent with injectable-class weight-loss efficacy.

Q: How does orforglipron work mechanistically?

Orforglipron is a small-molecule GLP-1 receptor agonist. It binds the GLP-1 receptor at an allosteric site distinct from where native GLP-1 or peptide analogs like semaglutide bind, but it triggers similar downstream G-protein signalling. The clinical effects — appetite suppression, slowed gastric emptying, enhanced glucose-dependent insulin secretion — mirror injectable GLP-1 agonists. The critical pharmacokinetic difference is that orforglipron is stable in the gastrointestinal tract and absorbed reliably without food or timing restrictions.

Q: What makes oral orforglipron different from Rybelsus?

Rybelsus is an oral formulation of the peptide semaglutide, paired with the absorption enhancer SNAC. Peptide stability in the gastric environment is inherently unreliable, so Rybelsus must be taken on an empty stomach with a small sip of water and a 30-minute fast afterward. Orforglipron is a small molecule, not a peptide, so it is metabolically stable in the gut and has no food or timing restrictions. This is a practical convenience advantage that may broaden GLP-1 class adoption.

Q: How does orforglipron compare to tirzepatide and semaglutide?

On weight-loss efficacy, orforglipron (~12.4% at the FDA-approved 17.2 mg dose, ~14.3% at the 36 mg dose tested in ATTAIN-1) is comparable to injectable semaglutide 2.4 mg (~14.9% in STEP 1) but below tirzepatide 15 mg (~22.5% in SURMOUNT-1) and retatrutide 12 mg (~28.7% in Phase 3 TRIUMPH-4, December 2025). The differentiator is oral convenience. Orforglipron expands GLP-1 class access for patients who resist injectables, but it does not match the weight-loss ceiling of dual and triple agonists.

Q: Is orforglipron available for research?

Orforglipron as a finished drug product is proprietary to Eli Lilly. Remy Peptides does not supply orforglipron. For laboratories characterising oral GLP-1 receptor pharmacology, the published ACHIEVE and ATTAIN clinical pharmacology disclosures are the primary reference. Remy Peptides supplies HPLC-verified retatrutide pens as its next-generation obesity reference compound for in-vitro research.

Eli Lilly’s once-daily small-molecule GLP-1 receptor agonist, FDA approved as Foundayo on April 1, 2026 for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity. The first non-peptide oral GLP-1 agonist, free of the food-and-timing restrictions that constrain Rybelsus. ATTAIN-1 reported ~14.3% weight loss at the 36 mg trial dose; the approved Foundayo label caps maintenance at 17.2 mg (~12.4% at 72 weeks).

Remy Peptides Editorial Team · Updated June 4, 2026

Fact-checked · Reviewed by Remy Peptides Editorial Board

Update History ▾

June 4, 2026: Added ATTAIN-MAINTAIN (NCT06584916) to the Phase 3 programme table and cited the ClinicalTrials.gov registry record for the Phase 3b maintenance trial alongside the existing Nature Medicine readout.
May 23, 2026: Added Lilly ATTAIN-MAINTAIN press readout (May 12, 2026) on Foundayo and lower-dose Zepbound holding weight loss after switch from max-tolerated Wegovy with modest regain (~0.9–5 kg by cohort); added ATTAIN-1/-2 post-hoc geriatric data (adults ≥65, May 2026); added ACHIEVE-4 sustained T2D + weight benefit at extended follow-up.
May 18, 2026: Added second May 2026 research update on ATTAIN-MAINTAIN Phase 3b (Aronne et al, Nat Med, PMID 42120723) — first Phase 3 data on orforglipron preserving weight loss after stopping injectable tirzepatide or semaglutide.
May 18, 2026: Added May 2026 research update on the Zaman & Amin Expert Opinion on Pharmacotherapy positioning review (PMID 42138103), which frames orforglipron as a route-preference option rather than an efficacy leader and flags four gating uncertainties: durability, persistence, affordability, and real-world safety.
May 17, 2026: Corrected Foundayo indication — FDA approval (April 1, 2026) is for chronic weight management, not type 2 diabetes; ACHIEVE supports the separate T2D filing path. Added approved-label dose context (17.2 mg cap, ~12.4% at 72 weeks) alongside the 36 mg ATTAIN-1 trial data. Refreshed retatrutide comparator to Phase 3 TRIUMPH-4 (28.7%).
April 22, 2026: Initial publication of dedicated compound profile

TL;DR — What Is Orforglipron?

Orforglipron (LY3502970) is Eli Lilly’s once-daily oral non-peptide GLP-1 receptor agonist, FDA approved under the brand name Foundayo on April 1, 2026 for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity. Unlike Rybelsus (an oral formulation of the peptide semaglutide), orforglipron is a small molecule that is metabolically stable in the gastrointestinal tract and has no food or timing restrictions. In ATTAIN-1, orforglipron 36 mg produced approximately 14.3% weight loss at 72 weeks; the FDA-approved Foundayo label caps maintenance at 17.2 mg (~12.4% at 72 weeks) — both ranges sit in the same band as injectable semaglutide and mark the first oral GLP-1 with injectable-class efficacy.

Key Takeaways

Architecture: Small-molecule non-peptide GLP-1 receptor agonist — not a peptide drug.
Sponsor: Eli Lilly — same company as tirzepatide and retatrutide.
Dosing: Once-daily oral tablet. No food or timing restrictions, unlike Rybelsus.
Regulatory: FDA approved as Foundayo on April 1, 2026 for chronic weight management.
ATTAIN-1 efficacy: ~14.3% at the 36 mg trial dose, ~12.4% at the 17.2 mg label-cap dose (72 weeks).
Positioning: Oral convenience matching injectable-class efficacy — but below tirzepatide and retatrutide on weight-loss ceiling.

What Is Orforglipron?

Orforglipron (development code LY3502970) is Eli Lilly’s once-daily oral GLP-1 receptor agonist. The critical structural distinction: it is a small-molecule non-peptide. Every other clinically meaningful GLP-1 agonist — semaglutide, liraglutide, dulaglutide, tirzepatide, retatrutide — is a peptide or engineered peptide variant. Peptides are not natively stable in the gastric environment, which is why they are either injected or paired with absorption enhancers (as in Rybelsus).

Because orforglipron is a small molecule, it survives the GI tract intact and absorbs reliably without food or timing restrictions. This is the single most consequential pharmacokinetic difference in the oral GLP-1 space. Orforglipron received FDA approval under the brand name Foundayo on April 1, 2026 for chronic weight management. For the full approval timeline and current regulatory status, see Is orforglipron approved?

Mechanism of Action

Orforglipron binds the GLP-1 receptor at an allosteric site distinct from the orthosteric pocket where native GLP-1 and peptide analogs like semaglutide bind. Despite the different binding geometry, orforglipron triggers similar downstream G-protein signalling and produces clinically comparable effects:

Central appetite suppression: Reduced food intake via hypothalamic and brainstem GLP-1 receptor activation.
Slowed gastric emptying: Prolonged satiety and attenuated postprandial glucose rise.
Glucose-dependent insulin secretion: Improved HbA1c without hypoglycemia risk.
Suppressed glucagon secretion: Reduced hepatic glucose output.

The practical implication of non-peptide architecture is pharmacokinetic rather than pharmacodynamic. Orforglipron is absorbed reliably regardless of food intake or timing — a sharp contrast with Rybelsus, which requires dosing on an empty stomach with a small sip of water followed by a 30-minute fast. For patients and laboratories comparing oral options, this is the decisive differentiator. See oral obesity drugs in 2026 for class context.

Phase 3 Programmes — ACHIEVE & ATTAIN

Orforglipron’s Phase 3 dataset is organised into two programmes: ATTAIN for obesity (supporting the approved Foundayo label) and ACHIEVE for type 2 diabetes (supporting a separate filing path). Eli Lilly tested 3, 12, 24, and 36 mg once-daily doses across the programmes; the FDA-approved Foundayo maintenance dose caps at 17.2 mg.

Orforglipron Phase 3 Programme Overview

Programme	Focus	Headline readout
ACHIEVE-1	Type 2 diabetes monotherapy	HbA1c reduction ~1.3–1.6%
ACHIEVE-2–5	T2D add-on / special populations	Consistent glycemic & weight effect
ATTAIN-1	Obesity without T2D, 72 wk	~14.3% weight loss at 36 mg
ATTAIN-2	Obesity + T2D	Reported 2025
ATTAIN-MAINTAIN	Weight-loss maintenance after injectable GLP-1/GIP switch (Phase 3b)	Held 74.7% (post-tirzepatide) and 79.3% (post-semaglutide) of weight loss at 52 wk

Regulatory status: Foundayo (orforglipron for chronic weight management) was FDA approved on April 1, 2026 under the Commissioner’s National Priority Voucher pilot programme. A separate T2D filing path is supported by the ACHIEVE programme. For a running regulatory view, see the Foundayo FDA approval tracker.

Efficacy Data — ATTAIN-1

ATTAIN-1 was a 72-week, randomised, placebo-controlled Phase 3 trial in adults with obesity without type 2 diabetes. Orforglipron 36 mg once daily produced approximately 14.3% mean weight loss at 72 weeks; lower trial doses (3, 12, 24 mg) produced proportionally less, yielding a clean dose-response. The FDA-approved Foundayo label caps maintenance dosing at 17.2 mg, which delivered approximately 12.4% weight loss at 72 weeks at the highest approved dose.

Two framing points matter for positioning:

Oral efficacy achieves injectable-class weight loss. Orforglipron’s ~14.3% is comparable to injectable semaglutide 2.4 mg in STEP 1 (~14.9% at 68 weeks). This is the first time an oral GLP-1 agent has matched the injectable benchmark.
It does not match dual or triple agonists. Tirzepatide 15 mg produced ~22.5% in SURMOUNT-1 and retatrutide 12 mg produced ~24.2% in Phase 2. Orforglipron’s weight-loss ceiling is meaningfully below the mono-molecule multi-receptor agents.

The glycemic data from ACHIEVE-1 (HbA1c reductions in the 1.3–1.6% range) is competitive with injectable semaglutide in diabetes populations, which supports the Foundayo type 2 diabetes label. For a focused oral-class comparison, see oral obesity drugs 2026. For a head-to-head framing, see retatrutide vs orforglipron.

May 2026 Research Update — ATTAIN-MAINTAIN Phase 3b

A Phase 3b maintenance trial in Nature Medicine (Aronne et al, May 12, 2026) tested whether orforglipron could preserve weight loss in 376 adults who had already lost weight on injectable GLP-1s. Over 52 weeks, orforglipron maintained 74.7% of weight loss in patients previously on tirzepatide (vs 49.2% on placebo; Δ 25.5%, 95% CI 14.5–36.5; P<0.001) and 79.3% in patients previously on semaglutide (vs 37.6%; Δ 41.7%, 95% CI 24.4–59.0; P<0.001). Adverse events were predominantly mild-to-moderate GI. This is the first Phase 3 evidence that an oral GLP-1 can hold the line on weight loss achieved by injectable incretins.

May 12, 2026 Update — Foundayo + Lower-Dose Zepbound Maintain Weight After Wegovy Step-Down

Lilly’s May 12, 2026 press readout of two late-phase trials reported that both Foundayo (orforglipron) and lower-dose Zepbound (tirzepatide) maintained weight loss after participants switched from max-tolerated injectable Wegovy, with only ~modest regain (~0.9 kg post-semaglutide, ~5 kg post-tirzepatide) across the maintenance period. The result repositions Foundayo as a viable oral maintenance step-down option after injectable GLP-1 induction and reshapes the maintenance-dosing narrative for the wider GLP-1 class.

May 2026 Update — ATTAIN-1/-2 Post-Hoc in Older Adults (≥65)

A post-hoc analysis of ATTAIN-1 and ATTAIN-2 showed adults aged 65 and older achieved weight loss comparable to younger participants on Foundayo, supporting use in older populations and broadening the relevant age band beyond the headline pivotal cohort.

April 2026 Update — ACHIEVE-4 Sustained T2D + Weight Benefit

ACHIEVE-4 reported sustained glycemic control and weight benefit on orforglipron at extended follow-up in adults with type 2 diabetes, supporting the forthcoming diabetes indication filing on top of the obesity-only Foundayo label.

Safety & Tolerability

Orforglipron’s safety profile is consistent with the GLP-1 class:

Most common AEs: nausea, diarrhea, vomiting, constipation, decreased appetite — canonical GLP-1 GI profile, concentrated in dose-escalation.
Severity: Most events mild to moderate; frequency diminishes with continued exposure.
Discontinuation: Reported in the typical single-digit-percent range in ATTAIN and ACHIEVE trials at top doses, comparable to injectable GLP-1 agents.
Cardiovascular: No unexpected signals in the Phase 3 dataset to date.
Class warnings: Thyroid C-cell tumor boxed warning carried forward from the GLP-1 class based on rodent data; human relevance remains uncertain.

Because orforglipron is oral and small-molecule, there is no injection-site reaction class typical of subcutaneous peptide drugs. This simplifies long-term adherence.

How It Compares — Orforglipron vs Class

Orforglipron’s strategic position is defined by the intersection of oral convenience and injectable-class efficacy:

vs Rybelsus: Same oral route, but orforglipron has no food/timing restrictions. Efficacy is similar at their respective top doses.
vs injectable semaglutide (Ozempic/Wegovy): Comparable weight-loss efficacy; oral route is the convenience differentiator.
vs Tirzepatide (Mounjaro/Zepbound): Tirzepatide’s dual GLP-1/GIP mechanism produces substantially more weight loss (~22.5% vs ~14.3%). Injectable route is the cost for that extra efficacy.
vs Retatrutide profile: Retatrutide’s triple agonism produces the deepest weight loss in the pipeline (~24.2% Phase 2). Orforglipron is not in the same efficacy tier, but it is in a different convenience tier.
vs CagriSema: CagriSema is injectable combination therapy with ~22.7% weight loss in REDEFINE 1. Orforglipron wins on route, CagriSema wins on efficacy.

The clinical and commercial question orforglipron answers is: how much oral convenience is worth, relative to 7–10 percentage points more weight loss from an injectable dual or triple agonist? For patients resistant to injectables, orforglipron is likely the preferred first-line agent. For patients seeking maximum weight loss, it is not competitive with tirzepatide or retatrutide.

May 2026 Research Update — Clinical-Position Review

A narrative review in Expert Opinion on Pharmacotherapy (Zaman & Amin, May 15, 2026) frames orforglipron as a meaningful expansion of obesity pharmacotherapy for patients who prefer oral routes, but cautions that comparative efficacy may not exceed leading injectable incretins. The authors flag four uncertainties as the gating issues: long-term durability, persistence on therapy, affordability, and real-world safety. The review positions orforglipron as a route-preference option rather than an efficacy leader, with clinical value depending on tolerability, access, and individualised goals rather than headline weight loss alone.

Research Use Notes

Orforglipron as a finished drug product is proprietary to Eli Lilly and is not supplied as a research-grade reference standard through mainstream channels. Laboratories characterising oral GLP-1 receptor pharmacology typically rely on the published ACHIEVE and ATTAIN clinical pharmacology disclosures and class-adjacent oral GLP-1 research compounds.

Remy Peptides supplies HPLC-verified retatrutide pens (Janoshik Analytical Batch RETP002, 99.262% purity) as its anchor next-generation obesity reference compound. Retatrutide is the unimolecular triple agonist at the mechanistic ceiling of the obesity pipeline — the logical reference for laboratories comparing novel oral and injectable GLP-1-class mechanisms. See the retatrutide in Dubai guide for full laboratory context.

All Remy Peptides products are supplied for in-vitro laboratory research only. Not for human or veterinary use. UAE MoHAP Circular 17/2022 compliance statement.

Frequently Asked Questions

What is orforglipron?

Orforglipron (LY3502970) is Eli Lilly’s once-daily oral non-peptide GLP-1 receptor agonist. Unlike semaglutide or tirzepatide, which are peptide drugs requiring injection or special absorption chemistry, orforglipron is a small-molecule GLP-1 agonist that can be taken as a conventional oral tablet without food or timing restrictions. It received FDA approval under the brand name Foundayo for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity.

Is orforglipron approved?

Yes. Orforglipron received FDA approval under the brand name Foundayo on April 1, 2026 for chronic weight management. It is the first non-peptide oral GLP-1 receptor agonist to reach market. The ACHIEVE programme supports a separate type 2 diabetes filing path; the approved Foundayo label is for weight management. For the latest regulatory status, see our approval tracker.

How much weight loss does orforglipron produce?

In ATTAIN-1, the pivotal Phase 3 obesity trial, orforglipron 36 mg once daily produced approximately 14.3% mean weight loss at 72 weeks in adults with obesity. This is comparable to injectable semaglutide 2.4 mg in STEP 1 (~14.9% at 68 weeks), making orforglipron the first oral GLP-1 agent with injectable-class weight-loss efficacy.

How does orforglipron work mechanistically?

Orforglipron is a small-molecule GLP-1 receptor agonist. It binds the GLP-1 receptor at an allosteric site distinct from where native GLP-1 or peptide analogs like semaglutide bind, but it triggers similar downstream G-protein signalling. The clinical effects — appetite suppression, slowed gastric emptying, enhanced glucose-dependent insulin secretion — mirror injectable GLP-1 agonists. The critical pharmacokinetic difference is that orforglipron is stable in the gastrointestinal tract and absorbed reliably without food or timing restrictions.

What makes oral orforglipron different from Rybelsus?

Rybelsus is an oral formulation of the peptide semaglutide, paired with the absorption enhancer SNAC. Peptide stability in the gastric environment is inherently unreliable, so Rybelsus must be taken on an empty stomach with a small sip of water and a 30-minute fast afterward. Orforglipron is a small molecule, not a peptide, so it is metabolically stable in the gut and has no food or timing restrictions. This is a practical convenience advantage that may broaden GLP-1 class adoption.

How does orforglipron compare to tirzepatide and semaglutide?

On weight-loss efficacy, orforglipron (~14.3% in ATTAIN-1) is comparable to injectable semaglutide 2.4 mg (~14.9% in STEP 1) but below tirzepatide 15 mg (~22.5% in SURMOUNT-1) and retatrutide 12 mg (~24.2% in Phase 2). The differentiator is oral convenience. Orforglipron is expected to expand GLP-1 class access for patients who resist injectables, but it does not yet match the weight-loss ceiling of dual and triple agonists.

Is orforglipron available for research?

Orforglipron as a finished drug product is proprietary to Eli Lilly. Remy Peptides does not supply orforglipron. For laboratories characterising oral GLP-1 receptor pharmacology, the published ACHIEVE and ATTAIN clinical pharmacology disclosures are the primary reference. Remy Peptides supplies HPLC-verified retatrutide pens as its next-generation obesity reference compound for in-vitro research.

Our Research Standards

This article cites peer-reviewed studies, FDA filings, and ClinicalTrials.gov data. All claims are cross-referenced against primary sources. We update articles when new trial data or regulatory decisions are published. Read our editorial policy →

Editorial Review

Remy Peptides Editorial Team

Editorial Board, Remy Peptides

The Remy Peptides Editorial Board reviews research articles covering GLP-1 receptor agonists, triple agonists, and the obesity drug pipeline. Its review spans peptide analytical chemistry, HPLC purity validation, and clinical trial data interpretation.

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References & Citations

Eli Lilly. FDA approval of Foundayo (orforglipron) for chronic weight management. 2026. investor.lilly.com
Eli Lilly. ACHIEVE Phase 3 programme: Orforglipron in type 2 diabetes. investor.lilly.com
Eli Lilly. ATTAIN-1 Phase 3 obesity trial results. investor.lilly.com
Wharton S, Blevins T, Connery L, et al. Daily Oral GLP-1 Receptor Agonist Orforglipron for Adults with Obesity. N Engl J Med. 2023;389(10):877-888. nejm.org
Frías JP, Hsia S, Eyde S, et al. Efficacy and safety of oral orforglipron in patients with type 2 diabetes. Lancet. 2023;402(10403):693-704. thelancet.com
ClinicalTrials.gov. ATTAIN-1: A Study of Daily Oral Orforglipron in Adult Participants With Obesity. clinicaltrials.gov
Zaman W, Amin A. Orforglipron and the emergence of oral GLP-1 therapy for obesity: efficacy, safety, and clinical positioning. Expert Opin Pharmacother. 2026 May 15. PMID 42138103. pubmed.ncbi.nlm.nih.gov
Aronne LJ, le Roux CW, et al. Maintenance of weight loss with orforglipron after discontinuation of injectable GLP-1 receptor agonists (ATTAIN-MAINTAIN). Nat Med. 2026 May 12. PMID 42120723. pubmed.ncbi.nlm.nih.gov
ClinicalTrials.gov. ATTAIN-MAINTAIN: A Study of Orforglipron for the Maintenance of Body Weight Reduction in Participants Who Have Obesity or Overweight With Weight-Related Comorbidities (NCT06584916). Eli Lilly and Company. Phase 3b. clinicaltrials.gov
Eli Lilly. Foundayo and lower-dose Zepbound helped people maintain weight loss after switching from higher doses of injectable incretin therapy — ATTAIN-MAINTAIN readout. May 12, 2026. prnewswire.com
Orforglipron linked to weight loss in older adults in ATTAIN post-hoc analysis. Patient Care Online. May 2026. patientcareonline.com
Orforglipron demonstrates sustained glycemic control and weight loss in Phase 3 ACHIEVE-4 trial. Pharmacy Times. April 2026. pharmacytimes.com