The first GLP-1 you swallow instead of inject cleared the FDA this April. Here is what the 72-week trial behind it actually measured — and why two different weight-loss numbers keep getting quoted.
ATTAIN-1 (NCT05869903) was a phase 3, randomized, double-blind, placebo-controlled trial that ran for 72 weeks across nine countries and Puerto Rico. It enrolled 3,127 adults with obesity, or overweight plus at least one weight-related condition — hypertension, dyslipidemia, obstructive sleep apnea, or cardiovascular disease. Nobody in the trial had diabetes.
Participants were randomized to once-daily oral orforglipron at 6mg (n=723), 12mg (n=725), or 36mg (n=730), or to placebo (n=949), all alongside a healthy diet and physical activity. Mean age was 45; 64% were women.
Orforglipron is not a shrunk-down injectable. It is a small-molecule, non-peptide GLP-1 receptor agonist — chemically closer to an ordinary tablet than to semaglutide or tirzepatide — which is why it survives the stomach without the food-and-water timing rules that oral semaglutide requires. The primary endpoint was percent change in body weight at week 72.
All three doses beat placebo on the primary endpoint (p<0.001 for every comparison).
Here is where the headline confusion comes from. Lilly's release quotes 12.4%, or 27.3 lb, at the top dose. The NEJM paper reports 11.2%. Both are correct — they are two different estimands. The 12.4% figure estimates what happens if everyone stays on the drug for the full 72 weeks. The 11.2% figure counts everyone as randomized, including people who stopped early. The second number is the more conservative real-world read.
Waist circumference, systolic blood pressure, non-HDL cholesterol, triglycerides, and glycemic markers all improved more on orforglipron than placebo. Gastrointestinal side effects were the most common adverse events and were typically mild to moderate. Discontinuation due to adverse events ran 5–10% across the orforglipron groups versus 3% on placebo.
On April 1, 2026, the FDA approved orforglipron as Foundayo for chronic weight management in adults — the first oral small-molecule GLP-1 receptor agonist for obesity, and one that can be taken any time of day with or without food or water.
Sources: Wharton S, Aronne LJ, Stefanski A, et al., New England Journal of Medicine, Sept 16 2025 (ATTAIN-1, NCT05869903, doi:10.1056/NEJMoa2511774) · American College of Cardiology journal scan, Sept 24 2025 · Eli Lilly FDA approval release, April 1 2026 · Drugs.com FDA approval history, updated May 24 2026. NEJM full text · Lilly approval release.
Daily changes the whole reminder problem. A missed weekly shot is one event you notice. A missed daily tablet is easy to lose track of entirely. Per the label, take a missed dose as soon as possible, never take two in the same day, and if you miss seven days or more in a row, call your prescriber before restarting.
The tablet strengths do not match the trial doses. Foundayo is supplied as 0.8, 2.5, 5.5, 9, 14.5, and 17.2mg tablets — not the 6/12/36mg used in ATTAIN-1. Titration starts at 0.8mg and steps up no sooner than every 30 days, to a maximum of 17.2mg. Go by the label and your prescriber, not by trial numbers you read online.
Oral contraceptives are a specific flag. The label warns birth control pills may not work as well on orforglipron, and advises a second method for 30 days after starting and for 30 days after each dose increase. That is easy to miss and worth a calendar entry.
The class warnings still apply. Foundayo carries a boxed warning for thyroid C-cell tumors, and the same cautions as injectable GLP-1s around pancreatitis, gallbladder disease, dehydration, and aspiration risk under anesthesia. An oral route is not a milder drug.
This article summarizes published clinical trial results, a professional-society trial summary, and manufacturer and FDA-approval information for general education. It is not medical advice. Individual results vary, and any decision about starting, adjusting, or stopping any GLP-1 medication should be made with a prescriber.