Orforglipron

Non-peptide oral GLP-1 receptor agonist (Eli Lilly, LY3502970 / OWL833), not approved, late-stage as of 2026. All cited studies are orforglipron-specific phase 1 to phase 3 trials. Keep distinct from danuglipron (Pfizer, oral small molecule, discontinued), the injectable peptides semaglutide and tirzepatide (tirzepatide is dual GIP/GLP-1), retatrutide (triple agonist), and oral semaglutide (a peptide needing an absorption enhancer and a fasting protocol).

The side-effect profile is the class profile. Gastrointestinal events dominate: nausea, vomiting, diarrhea, and constipation, mostly mild to moderate and concentrated during dose escalation. Across the phase 3 trials, adverse events led to discontinuation in roughly 4% to 20% of participants depending on dose and trial, and the rate was higher at 36 mg. Used on its own it did not cause severe hypoglycemia, though that risk rises when it is combined with insulin or a sulfonylurea.

A small increase in resting pulse rate was seen, as with injectable GLP-1 drugs. A pooled analysis of the phase 3 trials found no signal of liver toxicity, and a small number of mild pancreatitis cases were reported in the obesity programme. What is not known matters as much as what is. There are no long-term cardiovascular outcome data, no data on how durable the weight loss is after stopping, and no established safety in pregnancy. It is not a treatment for type 1 diabetes.

Orforglipron slows gastric emptying, and that is the interaction touching the most drugs: anything swallowed alongside it can be absorbed more slowly and reach a lower peak. The effect is largest after the first dose and after each dose increase, then fades with continued use; acetaminophen peak concentrations fell by about 28 percent after a first dose in healthy volunteers. Oral drugs with a narrow margin, such as phenytoin, digoxin and cyclosporine, are where that shift matters most. Absorption of oral hormonal contraceptives has not been formally studied, so contraceptive failure around initiation and each escalation is a live concern rather than a settled one.

Orforglipron is cleared mainly by CYP3A4, so moderate and strong CYP3A4 inducers such as rifampin, carbamazepine and St John's wort lower its exposure and can blunt the glucose and weight effects. Combining it with insulin or a sulfonylurea raises hypoglycemia risk; orforglipron on its own rarely drops glucose far, but it adds to agents that do.

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Orforglipron was originally discovered by Chugai Pharmaceutical and licensed to Eli Lilly, which advanced it under the code LY3502970 (also seen as OWL833). Phase 1 studies in healthy participants characterized its oral pharmacokinetics. A phase 2 trial in type 2 diabetes and a phase 2 trial in obesity, both reported in 2023, established the dose range and the weight and glucose effects. Lilly then ran two large phase 3 programmes: ATTAIN, in obesity, and ACHIEVE, in type 2 diabetes. The first phase 3 results arrived in 2025, with head-to-head comparisons against oral semaglutide and dapagliflozin reported in 2026.