The 2026 Obesity Drug Market: From Injections to Pills

In just the past two to three years, the obesity drug market has changed course three times. It began as a race over “how much weight can be lost,” moved through a race over “injection or pill,” and the focus is now shifting to “how to maintain the weight you lost.” This is a summary of the trends so far, as of September 2026.

The more hormone receptors a drug acts on, the greater the weight loss tends to be. Semaglutide (Wegovy, Ozempic), a single agonist (GLP-1), opened the market with about 15% weight loss at 2.4mg over 68 weeks, and high-dose Wegovy (7.2mg), approved by the US FDA on March 19, 2026, rose to an average of about 20.7% over 72 weeks. Tirzepatide (Zepbound, Mounjaro), a dual agonist (GLP-1+GIP), showed about 22.5% weight loss at the maximum dose over 72 weeks in the SURMOUNT-1 trial, the largest weight loss recorded among approved obesity drugs at present.

The one drawing attention now is the triple agonist (GLP-1+GIP+glucagon) retatrutide. It is still in development and not yet approved, but in the pivotal phase 3 TRIUMPH-1 trial (2,339 participants), average weight loss at 80 weeks was 28.3% at 12mg (2.2% with placebo), and in participants with a body mass index of 35 or higher followed out to 104 weeks, it reached an average of 30.3%. In TRIUMPH-4 (68 weeks), conducted in people with knee osteoarthritis, 12mg also produced an average weight loss of 28.7%. Data from all five phase 3 trials of the triple agonist are now in hand, and the developer has announced plans to file for US approval in the first quarter of 2027.

There has also been a big change in how the drugs are taken. Until now, most GLP-1 drugs were once-weekly injections, but from late 2025 the era of oral drugs has genuinely begun. Oral semaglutide 25mg (oral Wegovy) showed an average weight loss of 16.6% at 64 weeks in the phase 3 OASIS 4 trial (13.6% when reflecting real-world use), similar to injectable Wegovy; the US FDA approved it on December 22, 2025 as the first oral GLP-1 for weight management, and cumulative prescriptions passed 5 million within six months of launch. In Korea, an application for approval was filed with the Ministry of Food and Drug Safety in the first half of 2026 and is under review, with launch expected in 2027.

Orforglipron (brand name Foundayo), a small-molecule oral drug rather than a peptide, showed an average weight loss of 11.2% at 72 weeks in the phase 3 ATTAIN-1 trial. That is smaller than the injectables, but it gained FDA approval on April 1, 2026, with the advantage of having no demanding dosing conditions such as fasting or water restrictions. However, tirzepatide has a large molecular weight and is broken down in the stomach, which makes an oral form difficult, so Mounjaro and Zepbound still exist only as injections. As pills increase, overall GLP-1 prescriptions have also been confirmed to be rising again over the last four weeks.

As obesity comes to be treated as a chronic disease, the focus of interest is shifting from “how quickly can you lose weight” to “how do you maintain it.” SURMOUNT-MAINTAIN (2026, Lancet) had participants lose weight on the maximum tirzepatide dose for 60 weeks and then compared three paths during a 52-week maintenance period: the group that stayed on the maximum dose kept 96.5% of its initial weight loss, the group that dropped to 5mg kept 67.9%, and the group that stopped on placebo kept only 42.8%. ATTAIN-MAINTAIN (2026, Nature Medicine) looked at people who lost weight by injection and then switched to oral orforglipron: the group that lost weight with tirzepatide kept 74.7% of the loss, and the group that lost weight with semaglutide kept 79.3%.

The “quality” of weight loss has also become a new topic. Growing concern that up to 40% of the weight lost on GLP-1 drugs can be muscle has drawn attention to bimagrumab, an antibody that prevents muscle loss. In the phase 2b BELIEVE trial (72 weeks), when combined with semaglutide, 92.8% of the average 22.1% weight loss was fat; compared with semaglutide alone (15.7% weight loss, 71.8% fat), it preserved muscle while also producing greater weight loss.

Obesity drugs are being redefined as metabolic and organ-protective treatments whose indications extend beyond weight loss to cardiovascular disease, chronic kidney disease, metabolic dysfunction-associated fatty liver disease, sleep apnea, knee osteoarthritis, and chronic low back pain. As weight loss efficacy approaches that of gastric surgery, metabolic surgery is stagnating or declining, minimally invasive procedures such as endoscopic sleeve gastroplasty are settling into the middle ground between drugs and surgery, and cases of adding a GLP-1 to address weight regain after surgery are also increasing.

In US prescription share, Eli Lilly’s tirzepatide holds about 57% and Novo Nordisk’s semaglutide about 37%, and the gap has widened. Lilly has secured the deepest pipeline, with Zepbound and Mounjaro plus the oral drug orforglipron and the triple agonist retatrutide, while Novo is fighting back with high-dose and oral Wegovy and preparing a next-generation injectable that combines an amylin analog. In Korea, as of May 2026 Mounjaro’s prescription share was about 78%, far ahead of Wegovy (about 15%), and Hanmi Pharmaceutical’s efpeglenatide, the first GLP-1 obesity drug developed independently by a Korean drug company, has been designated for fast-track review, with approval targeted for October 2026 and launch within the year.

The obesity drug market has increased weight loss by moving from single to triple agonists, widened access by moving from injections to pills, and the axes of competition have now broadened to maintenance strategies that protect lost weight through dose adjustment or a switch to oral drugs, and to the quality of weight loss that preserves muscle. However, most triple agonists and next-generation candidates in Korea and abroad are still in clinical trials or under approval review, so whether they can actually be prescribed and how they are used should be confirmed with your treating medical team.

An herbal-medicine approach to weight loss differs in character from this drug trend, but it aims to manage appetite and condition so that the dietary standards you set can actually be kept. In an observational study in which ACRO Korean Medicine Clinic medical staff took part as co-first authors, participants also showed meaningful weight loss (118 people, 10 weeks of observation, average weight loss of about 7.64kg, with 94.9% losing 5% or more of their initial weight).

KakaoTalk consultation: https://pf.kakao.com/_VcUxmC / Phone reservations: 02-6925-1175 / Website: https://www.acrohani.com / 2F, 480 Gangnam-daero, 1-minute walk from Sinnonhyeon Station Exit 3

Main sources: OASIS 4 (NEJM 2025), ATTAIN-1 (NEJM 2025), ATTAIN-MAINTAIN (Nature Medicine 2026), SURMOUNT-1 (NEJM 2022) and SURMOUNT-MAINTAIN (Lancet 2026), STEP UP/Wegovy HD (FDA 2026.3), TRIUMPH-1 and 4 (Eli Lilly 2025-2026), BELIEVE and bimagrumab+semaglutide (Nature Medicine 2026). This text summarizes clinical results and announcements from regulators and pharmaceutical companies publicly available as of September 13, 2026; it does not recommend taking or prescribing any particular drug, and individual treatment decisions should be confirmed through consultation with a medical professional.

Reviewed by: Dr. Han Ji-young · Director, ACRO Korean Medicine Clinic. Last reviewed 2026-09-20

This article is provided for general information only, and results may differ depending on each person’s health condition and constitution. Please confirm an accurate diagnosis and treatment plan through a consultation with a specialist.