Mazdutide (IBI362)

The upside is concentrated in two places: weight loss that approaches the best incretins, and liver fat clearance that beats all of them. The strongest human evidence is the Phase 3 GLORY-1 trial showing about 14.84 percent weight loss at 48 weeks, per Ji 2025. Breadth is wide because the two receptors touch weight, glucose, lipids, blood pressure, and the liver at once, and the glucagon leg adds a hepatic and energy-expenditure mechanism that pure GLP-1 drugs simply do not have. Evidence quality is genuinely good for such a new drug, with a published Phase 3 study plus two peer-reviewed Phase 2 trials behind it. The key boundary is that all of it comes from Chinese adults, with no cardiovascular outcomes proof and no Western trial yet, so the numbers are strong but their generalizability is unconfirmed. That single caveat is the main reason the upside dimensions, strong as they are, do not push the overall score higher.

Efficacy (4.7/5.0): Efficacy is the high point. The Phase 3 GLORY-1 trial showed about 14.84 percent weight loss at 48 weeks on the 6 mg dose against roughly half a percent on placebo in 610 adults, per Ji 2025. Phase 2 obesity work hit about 11.3 percent at 24 weeks on 6 mg in 248 adults, per Ji 2023, and high-dose Phase 1b reached about 11.7 percent in just 12 weeks, per Zhang 2022. These are large, consistent, placebo-controlled effects.

On glucose, the Phase 2 diabetes trial cut HbA1c about 1.67 percent and got 73.5 percent of the 6 mg arm under an HbA1c of 7 percent, per Ji 2024. The reason efficacy is not a perfect 5 is the single-population caveat: every effect size comes from Chinese adults with lower baseline body weight, so the same numbers in a heavier Western population are not yet proven.

Breadth of Benefits (4.3/5.0): Breadth is wide because two receptors working together touch many systems. Weight falls, HbA1c drops, and the same trials reported triglycerides down roughly 27 to 37 percent, lower blood pressure, and substantially reduced serum uric acid, per Ji 2023. On top of that sits the standout liver fat reduction near 80 percent, per Ji 2025. The glucagon leg adds energy expenditure and hepatic fat clearance that pure GLP-1 drugs do not engage, which widens the metabolic footprint. The boundary on breadth is that several of these are surrogate markers rather than proven hard outcomes, and the absence of any cardiovascular event data means the cardiac dimension stays unproven despite the favorable numbers.

Evidence Quality (4.0/5.0): Evidence quality is genuinely good for a drug this new. There is a peer-reviewed Phase 1b study, two peer-reviewed Phase 2 trials, and a pivotal Phase 3 trial published in a top journal, per Ji 2025 and Ji 2023. Sample sizes are real, designs are randomized and placebo-controlled, and effects are large and internally consistent. Two deductions keep it from scoring higher. First, every pivotal trial enrolled only Chinese adults, so external validity to Western populations is untested. Second, there is no cardiovascular outcomes trial, which is the kind of study that turns marker improvements into proof of fewer heart events. Some of the largest weight figures also come from press releases not yet fully peer reviewed, which I weight below the published data.

Speed of Onset (3.6/5.0): Speed is moderate and follows the incretin pattern. Appetite suppression begins within the first weeks of dosing, but meaningful weight loss builds over months, with the headline 14.84 percent figure measured at 48 weeks, per Ji 2025. Liver fat reductions were likewise measured over multi-month windows in Phase 2, per Ji 2023. Reaching the 4 mg or 6 mg target also requires several weeks of slow titration before full effect. This is a slow-build tool, not something you feel resolve in days, which is why speed scores in the middle rather than high.

Durability (2.0/5.0): Durability is the weakest upside dimension. While dosing continues, the effect holds and even kept building past 48 weeks in extended data, which is a positive signal. The problem is what happens after stopping. No discontinuation or maintenance study exists for mazdutide specifically, and the wider incretin class shows that most lost weight returns within one to two years off the drug. Until a maintenance trial publishes, the safe assumption is that mazdutide is a stay-on-it tool whose benefits fade when you quit, which is exactly what drags this dimension down.

Bioindividuality Upside (3.8/5.0): Response varies in predictable ways, which lifts this dimension. People who start with high liver fat see the largest liver reductions, with high-baseline subgroups reaching near 80 percent versus smaller drops in those starting lower, per Ji 2025. Higher doses produce more weight loss, so there is a clear dose-response lever. The big open question is the population one: every responder profile here comes from Chinese adults, and how a different body-weight baseline and fat-distribution pattern in Western users would shift these responses is genuinely unknown. Predictable modifiers exist, but one of the biggest ones, ethnicity and baseline phenotype, remains untested.