Weight-Loss Drugs Ranked: GLP-1 to Retatrutide
The obesity drug revolution
In 2023 the world discovered that a class of drugs originally designed for diabetes could produce dramatic weight loss. By 2026 the category has expanded from first-generation weekly injections to oral pills, second-generation dual-agonists, and a third-generation triple-agonist called retatrutide that in trials produced average weight loss of around 24 percent of body weight. This slate ranks the main options by mechanism, efficacy, and current status.
The main drugs in order of generation
1. Semaglutide (Ozempic / Wegovy) - GLP-1 agonist, first gen, weekly injection
2. Tirzepatide (Mounjaro / Zepbound) - GLP-1 plus GIP dual agonist, second gen
3. Liraglutide (Saxenda) - older GLP-1, daily injection, less weight loss
4. Orforglipron - oral GLP-1, once daily pill, phase 3 data strong
5. Semaglutide oral (Rybelsus) - pill form, lower efficacy than injection
6. Retatrutide - triple agonist (GLP-1, GIP, glucagon), phase 3 ongoing
Average weight loss, semaglutide
15% of body weight
Average weight loss, tirzepatide
21% of body weight
Average weight loss, retatrutide (phase 2)
up to 24%
Weekly cost (US, out of pocket)
$900 to $1400
"We are in the middle of a complete transformation in how we treat obesity. These are not diet drugs. They are true medications for a chronic disease.
"Dr. Ania Jastreboff · Yale obesity medicine · 2024