A daily pill helped people lose 11.3 percent more body weight than a placebo over 36 weeks, and most of them never touched a needle. That is the headline number from the full Phase 2b results for aleniglipron, an oral weight-loss drug from Structure Therapeutics, published June 5 in Nature Medicine ↗ and presented the same afternoon at the American Diabetes Association meeting in New Orleans.
The 11.3 percent figure is placebo-adjusted, which means it is the extra weight lost on the drug after subtracting what the placebo group lost on its own. In plain terms, the people on the highest dose of aleniglipron lost about 27 pounds more than the people swallowing a dummy pill. That is the strongest number any oral weight-loss drug has posted outside of Lilly's program, and it matters because almost every blockbuster in this class so far has been an injection.
Why a pill is the hard part
Semaglutide ↗ and tirzepatide ↗, the drugs sold as Wegovy, Ozempic, Zepbound and Mounjaro, are peptides. Peptides are short chains of amino acids, and the gut digests them the way it digests the protein in a steak, which is why they are injected rather than swallowed. Getting that same appetite-suppressing effect from a molecule the stomach will not destroy has been the field's standing problem.
Aleniglipron sidesteps it. It is not a peptide at all. It is a small molecule, the kind of compact, stable chemical that survives the gut and can be pressed into a tablet, and it switches on the same GLP-1 receptor ↗ that the injectables hit. The receptor is the appetite-and-blood-sugar switch on cells in the gut, pancreas and brain. Hit it and people eat less.
What the trial actually showed
The ACCESS study randomized 230 adults who were either obese or overweight with at least one weight-related health problem. Everyone started at a low 5 mg dose and climbed to a maintenance dose of 45, 90 or 120 mg once a day. At 36 weeks, the placebo-adjusted weight loss came in at 8.2 percent, 9.8 percent and 11.3 percent across the three doses, each clearing statistical significance at the strictest level the trial set.
The responder numbers are the part a normal reader should hold onto. On the top dose, 86 percent of people lost at least 5 percent of their body weight, 70 percent lost at least 10 percent, and 38 percent lost at least 15 percent. On placebo, those same milestones were hit by 23 percent, 7 percent and 1 percent. The drug did not nudge a few people a little. It moved most people past the bars that almost nobody clears on their own.
The weight loss also kept going. In an open-label extension that followed patients past the core trial, people coming off the three doses reached 13.3, 16.2 and 15.3 percent total weight loss, evidence the curve had not flattened at 36 weeks. About one in ten patients (10.4 percent) stopped the drug because of side effects, and the side effects were the usual GLP-1 story: nausea and other gut complaints, mostly mild to moderate, fading over time.
The honest caveats
This is a mid-stage trial, not the final word. Phase 2b reads efficacy and safety in a few hundred people; the Phase 3 program that decides approval has not started, though Structure says it will begin in the third quarter of 2026 with a gentler 2.5 mg starting dose meant to blunt early nausea. And 11.3 percent placebo-adjusted, while excellent for a pill, still trails the best injectable numbers, where tirzepatide-class drugs have pushed past 20 percent in their own trials.
The lead author was Julio Rosenstock, a diabetes trialist whose name is on a long list of incretin studies, which puts the data in serious company rather than a press release alone. The competitive frame is the real story. Lilly's orforglipron is the oral drug everyone measures against, and a second small molecule landing double-digit placebo-adjusted loss with a clean tablet profile turns the oral weight-loss race into an actual race. The injection built the market. The pill is what decides who keeps it.