Orforglipron

An oral, once-daily, non-peptide small-molecule GLP-1 receptor agonist discovered by Chugai and developed by Lilly, approved by the FDA in April 2026 as Foundayo for chronic weight management; a US type 2 diabetes filing was planned for mid-2026 and no FDA action on it has been published, while the UK has approved both indications.

Also referenced as: Foundayo, LY3502970, OWL833, LY-3502970, Orforglipron calcium

Also appears in: Metabolic

What is Orforglipron?

Orforglipron is an orally active, once-daily agonist of the glucagon-like peptide-1 (GLP-1) receptor. It is not a peptide: it is a synthetic small molecule (development codes OWL833 and LY3502970) discovered by Chugai Pharmaceutical and licensed worldwide to Eli Lilly in September 2018, which binds the same receptor as semaglutide, liraglutide, and native GLP-1 but shares none of their amino-acid structure. Because it is not digested by gut proteases, it is absorbed as an ordinary tablet without the absorption enhancer that oral semaglutide requires, and the approved label allows it to be taken with or without food. It appears in the research-compound market because it is the first non-peptide GLP-1 agonist to reach approval, and because its small-molecule chemistry makes it easy to synthesize and sell as capsules or powder alongside injectable GLP-1 peptides.

How it works

• Direct GLP-1 receptor agonism — orforglipron binds a pocket in the upper helical bundle of the GLP-1 receptor formed by the extracellular domain, extracellular loop 2, and transmembrane helices 1, 2, 3, and 7, a site distinct from where the peptide hormone docks; the cryo-EM structure (PDB 6XOX) showed how a non-peptide ligand can stabilize the active receptor conformation (Kawai et al., Proceedings of the National Academy of Sciences, 117(47):29959–29967, 2020)
• G protein-biased partial agonism — the molecule is a partial agonist biased toward G protein activation over β-arrestin recruitment, which the structural work proposed as a consequence of the distinct receptor conformation it induces; whether that bias changes clinical outcomes in humans is inferred from receptor-level models rather than demonstrated directly (Kawai et al., PNAS, 2020; Tran et al., Molecular Metabolism, 105:102321, 2026)
• Species selectivity via Trp33 — activity depends on a primate-specific tryptophan (Trp33) in the receptor’s extracellular domain, so the compound is inactive at rodent GLP-1 receptors; the approved label states it is not pharmacologically active in rats or mice, and preclinical efficacy was shown in humanized GLP-1 receptor transgenic mice and nonhuman primates rather than ordinary rodents (Kawai et al., PNAS, 2020)
• Downstream incretin effects — like peptide GLP-1 agonists, receptor activation produces glucose-dependent insulin secretion, reduced glucagon, slowed gastric emptying, and reduced appetite and food intake, which account for the HbA1c and body weight reductions seen in trials (Frias et al., The Lancet, 2023; Wharton et al., New England Journal of Medicine, 2023)

Research status

Orforglipron has one of the largest Phase 3 programs of any oral obesity or diabetes drug, and as of late October 2026 it is an FDA-approved product for weight management, with the type 2 diabetes indication approved in the UK and recommended in the EU; a US filing for that indication was planned for mid-2026, and no FDA action on it has been published.

• Phase 2: in 272 adults with obesity without diabetes, 36 weeks of orforglipron produced mean weight reductions of 9.4% to 14.7% across doses versus 2.3% with placebo (Wharton et al., New England Journal of Medicine, 389(10):877–888, 2023). In type 2 diabetes, a 26-week dose-response study against placebo and dulaglutide showed HbA1c reductions of up to 2.1 percentage points versus 0.43 with placebo and 1.1 with dulaglutide (Frias et al., The Lancet, 402(10400):472–483, 2023).
• ATTAIN-1 (NCT05869903): 3,127 adults with obesity without diabetes randomized to 6, 12, or 36 mg or placebo for 72 weeks; mean weight change was −7.5%, −8.4%, and −11.2% versus −2.1% with placebo, with 54.6% of the 36 mg group losing 10% or more; adverse events led to discontinuation in 5.3% to 10.3% of orforglipron patients versus 2.7% on placebo (Wharton et al., New England Journal of Medicine, 393(18):1796–1806, 2025).
• ATTAIN-2 (NCT05872620): 1,613 adults with obesity or overweight and type 2 diabetes treated for 72 weeks; mean weight change was −5.1%, −7.0%, and −9.6% at 6, 12, and 36 mg versus −2.5% with placebo, with discontinuations for adverse events of 6.1% to 9.9% versus 4.1% (Horn et al., The Lancet, 406(10522):2927–2944, published online November 2025).
• ACHIEVE-1 (NCT05971940): 559 adults with early type 2 diabetes on diet and exercise alone; at 40 weeks HbA1c fell 1.24 to 1.48 percentage points versus 0.41 with placebo, reaching mean values of 6.5% to 6.7%, with adverse-event discontinuations of 4.4% to 7.8% versus 1.4% (Rosenstock et al., New England Journal of Medicine, 393(11):1065–1076, 2025).
• ACHIEVE-2, -3, and -5: an open-label non-inferiority trial against dapagliflozin met its primary objective at 40 weeks, with HbA1c reductions of 1.23 to 1.56 points versus 0.81 (Welch et al., The Lancet, 408(10550):125–140, 2026); against oral semaglutide 7 and 14 mg, both orforglipron doses met non-inferiority and then showed superiority at 52 weeks, with HbA1c reductions of 1.71 and 1.91 points versus 1.23 and 1.47 (Rosenstock et al., The Lancet, 407(10534):1147–1160, 2026); added to titrated insulin glargine, all three doses were superior to placebo without increasing clinically significant hypoglycemia (Giorgino et al., JAMA, 336(5):389–399, 2026).
• ACHIEVE-4 (NCT05803421): an event-driven cardiovascular safety trial of 2,749 adults with type 2 diabetes and obesity or overweight at increased cardiovascular risk; over a median two years, four-point MACE occurred in 4.2% on orforglipron versus 5.0% on insulin glargine (hazard ratio 0.84), meeting non-inferiority; gastrointestinal events were the most frequent adverse event and the most common reason for discontinuation (Klein et al., The Lancet, 408(10564):1557–1570, 2026). A cardiovascular superiority or outcomes benefit comparable to that shown for some peptide GLP-1 agonists has not been demonstrated.
• Maintenance: in the Phase 3b ATTAIN-MAINTAIN trial, participants switched from tirzepatide or semaglutide retained about 75% to 79% of their prior weight loss on orforglipron over 52 weeks versus 38% to 49% on placebo; the trial had no arm continuing the injectable (Aronne et al., Nature Medicine, 32(7):2679–2687, 2026).
• Regulatory: the FDA approved orforglipron as Foundayo on April 1, 2026, for chronic weight management in adults with obesity, or overweight with at least one weight-related condition, as the first new molecular entity under the Commissioner’s National Priority Voucher program; the label carries the class boxed warning for thyroid C-cell tumors and warnings for acute pancreatitis, severe gastrointestinal reactions, acute kidney injury, hypoglycemia, hypersensitivity, diabetic retinopathy complications, acute gallbladder disease, and pulmonary aspiration under anesthesia. Lilly said in June 2026 that it would submit the type 2 diabetes indication to the FDA by the end of that quarter under the same voucher program; no FDA decision on that indication had been published as of late October 2026, and the July 2026 label lists weight management only. The UK’s MHRA approved Foundayo for obesity and type 2 diabetes on August 10, 2026, and the European Medicines Agency’s CHMP adopted a positive opinion covering both obesity and type 2 diabetes at its October 12–15, 2026 meeting, pending a European Commission decision.

Common dosage forms

The approved pharmaceutical product is a film-coated oral tablet (Foundayo) supplied in six strengths of 0.8, 2.5, 5.5, 9, 14.5, and 17.2 mg, taken once daily with or without food. The Phase 2 and Phase 3 trials used an investigational capsule labeled by a different milligram convention (1, 3, 6, 12, 24, and 36 mg, with 3, 6, 12, and 36 mg as the studied maintenance doses); the label describes the trial data as coming from an investigational formulation at equivalent tablet doses, and Lilly’s medical information states that capsules and tablets are not substitutable milligram for milligram because the tablet is absorbed more efficiently, so the 36 mg trial capsule corresponds to the 17.2 mg tablet. Research vendors list orforglipron as capsules of stated milligram content or as bulk powder marked for research use only; unlike most compounds on those catalogs it is neither a peptide nor injectable, and vendor milligram labels may follow either the trial or the commercial convention.

Key considerations

• Status: orforglipron is an FDA-approved prescription drug (Foundayo, April 1, 2026) for chronic weight management, which is the basis of its FDA Approved status; the type 2 diabetes indication is approved in the UK and recommended in the EU but is not yet on the US label, so any US use for glycemic control alone remains off-label
• Not a peptide: orforglipron is a small organic molecule (supplied as a calcium salt, molecular weight about 902) with no amino-acid backbone; it is grouped with peptides only because it targets the GLP-1 receptor and is sold through the same channels, and purity or identity testing designed for peptides (for example, mass-spectrometry against a peptide sequence) does not apply to it
• Class safety signals: gastrointestinal adverse events drove discontinuation rates of roughly 1.5 to more than 5 times those of placebo across the placebo-controlled Phase 3 trials (for example 5.3% to 10.3% versus 2.7% in ATTAIN-1 and 4.4% to 7.8% versus 1.4% in ACHIEVE-1); the label’s warnings mirror the GLP-1 agonist class, and published correspondence has questioned how pancreatitis risk was assessed in the diabetes trials (Biswas et al., JAMA, October 2026, with reply from Giorgino et al.)
• Evidence gaps: weight loss at the highest dose (about 11% at 72 weeks in adults without diabetes, about 10% with diabetes) is smaller than reported for injectable tirzepatide or semaglutide; data beyond 72 weeks of continuous treatment, a cardiovascular outcome benefit (as opposed to safety), and the clinical meaning of G protein-biased signaling are not established, and the one maintenance trial lasted a year and lacked a continued-injectable comparator
• Naming and dose confusion: trial doses (up to 36 mg capsules) and approved tablet strengths (up to 17.2 mg) refer to different formulations of the same drug, and the code names OWL833 and LY3502970 both denote orforglipron; because it is inactive at rodent receptors, animal data from standard mouse or rat models should be treated with skepticism