blog-224410175772

The landscape of the obesity treatment market has shifted three times in the last 2-3 years. Starting with a competition over the extent of weight loss ("how much weight can be lost"), it moved to a competition over administration methods ("injection or pill"), and now the focus is shifting to "how to maintain the lost weight." We have summarized the trends up to September 2026.

The extent of weight loss with obesity treatments tends to increase as the number of hormone receptors they act on grows. Semaglutide (Wegovy, Ozempic), a single agonist (GLP-1), opened the market with approximately 15% weight loss over 68 weeks at 2.4mg. High-dose Wegovy (7.2mg), approved by the U.S. FDA on March 19, 2026, achieved an average of approximately 20.7% over 72 weeks. Tirzepatide (Zepbound, Mounjaro), a dual agonist (GLP-1+GIP), showed approximately 22.5% weight loss at the maximum dose over 72 weeks in the SURMOUNT-1 trial, recording the largest weight loss among currently approved obesity treatments.

Currently, the focus is on the triple agonist (GLP-1+GIP+Glucagon) Retatrutide. Although still in the developmental stage before approval, in the pivotal Phase 3 TRIUMPH-1 trial (2,339 participants), the average weight loss over 80 weeks was 28.3% at 12mg (compared to 2.2% for placebo). Extended observation of participants with a BMI of 35 or higher for up to 104 weeks showed an average of 30.3% weight loss. In TRIUMPH-4 (68 weeks), which included participants with knee osteoarthritis, an average of 28.7% weight loss was observed at 12mg. The triple agonist has secured all five Phase 3 data sets, and the developer has announced plans to apply for U.S. approval in Q1 2027.

There has also been a significant change in administration methods. Until now, most GLP-1 class drugs were once-weekly injections, but the era of oral medications truly began in late 2025. Oral semaglutide 25mg (oral Wegovy) showed similar results to injectable Wegovy, with an average of 16.6% weight loss over 64 weeks in the OASIS 4 Phase 3 trial (13.6% reflecting real-world use). It was approved by the U.S. FDA as the first oral GLP-1 for weight management on December 22, 2025, and accumulated over 5 million prescriptions within six months of its launch. In Korea, an application for KFDA approval was submitted in the first half of 2026 and is currently under review, with launch projected for 2027.

The non-peptide small molecule oral drug Orforglipron (brand name Foundayo) received FDA approval on April 1, 2026. In the ATTAIN-1 Phase 3 trial, it showed an average of 11.2% weight loss over 72 weeks, which is less than injectables, but it has the advantage of not having strict administration conditions like fasting or water restrictions. However, due to its large molecular weight, tirzepatide is broken down in the stomach, making oral formulation difficult, so Mounjaro and Zepbound remain injection-only. With the increase in pills, a recent trend of increasing overall GLP-1 prescriptions over the past four weeks has also been observed.

As obesity is treated as a chronic disease, the focus of interest is shifting from "how quickly weight can be lost" to "how to maintain it." SURMOUNT-MAINTAIN (2026, Lancet) compared three maintenance strategies over 52 weeks after 60 weeks of weight loss with the maximum dose of tirzepatide. The group that maintained the maximum dose retained 96.5% of their initial weight loss, the group that reduced to 5mg retained 67.9%, and the group that discontinued with placebo retained only 42.8%. ATTAIN-MAINTAIN (2026, Nature Medicine) examined cases where participants switched from an injection for weight loss to oral Orforglipron. The group that lost weight with tirzepatide maintained 74.7% of their weight loss, and the group that lost weight with semaglutide maintained 79.3%.

The 'quality' of weight loss is also a new topic. With growing concerns that up to 40% of weight loss from GLP-1 class drugs could be muscle, the antibody Bimagrumab, which prevents muscle loss, is gaining attention. In the Phase 2b BELIEVE trial (72 weeks), when combined with semaglutide, an average of 92.8% of the 22.1% weight loss was fat, which was a greater extent of weight loss while preserving muscle compared to semaglutide alone (15.7% weight loss, 71.8% fat ratio).

Obesity treatments are being redefined as metabolic and organ-specific treatments, expanding their indications beyond weight loss to cardiovascular disease, chronic kidney disease, metabolic dysfunction-associated steatotic liver disease, sleep apnea, knee osteoarthritis, and chronic low back pain. As the efficacy of weight loss approaches that of gastric surgery, metabolic surgery is seeing a stagnation or decrease, while less invasive procedures like endoscopic sleeve gastroplasty are establishing themselves as an intermediate zone between medication and surgery. Additionally, there is an increasing number of combination cases where GLP-1 is added for weight regain after surgery.

In the U.S. prescription market share, Eli Lilly's tirzepatide has widened its lead with approximately 57%, compared to Novo Nordisk's semaglutide at approximately 37%. Lilly has secured the most robust pipeline with Zepbound and Mounjaro, along with the oral drug Orforglipron and the triple agonist Retatrutide. Novo is counterattacking with high-dose and oral Wegovy, while also preparing next-generation injectable drugs combining amylin analogs. In Korea, as of May 2026, Mounjaro's prescription share was approximately 78%, significantly ahead of Wegovy (approximately 15%). Hanmi Pharmaceutical's Efpeglenatide, the first GLP-1 obesity new drug independently developed by a Korean pharmaceutical company, has been designated for expedited review, aiming for approval in October 2026 and launch within the year.

The obesity treatment market has expanded the extent of weight loss from single to triple agonists, increased accessibility from injections to pills, and now the competitive axis has broadened to include maintenance strategies that preserve lost weight through dose adjustment or oral conversion, as well as the quality of weight loss that conserves muscle. However, since most triple agonists and next-generation candidates, both domestically and internationally, are still in clinical trials or regulatory review stages, it is accurate to confirm their actual availability for prescription and usage with your medical professional.

Dietary treatment approached with Korean medicine differs from these drug trends, but it aims to help manage appetite and condition to actually adhere to established dietary habits. In an observational study where medical staff from Acro Korean Medicine Clinic participated as co-first authors, participants showed meaningful weight loss results (118 participants, 10-week observation, average approximately 7.64kg weight loss, 94.9% lost more than 5% of initial body weight).

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

Key References: OASIS 4 (NEJM 2025), ATTAIN-1 (NEJM 2025), ATTAIN-MAINTAIN (Nature Medicine 2026), SURMOUNT-1 (NEJM 2022)·SURMOUNT-MAINTAIN (Lancet 2026), STEP UP/Wegovy HD (FDA 2026.3), TRIUMPH-1·4 (Eli Lilly 2025-2026), BELIEVE·bimagrumab+semaglutide (Nature Medicine 2026). This article summarizes clinical results and regulatory/pharmaceutical company announcements publicly available as of September 13, 2026, and is not intended to recommend the use or prescription of specific drugs. Individual treatment decisions should be confirmed through consultation with a medical professional.

Reviewed by: Director Han Ji-young · Director of Acro Korean Medicine Clinic Last reviewed 2026-09-20

This article is for general informational purposes only, and results may vary depending on an individual's health condition and constitution. Please consult with a specialist for an accurate diagnosis and treatment plan.