Research · Evidence roundup

Two new GLP-1 trials, one direction: what mazdutide and orforglipron mean together

By Erik Jones · Jun 15, 2026 · 8 min read

Two trials, one direction

The editorial that accompanied the two trials made the framing explicit. Obesity isn’t one disease with one cause; it is a heterogeneous condition driven by a different mix of genetics, physiology, behavior, and environment from one person to the next. That heterogeneity is exactly why having more drugs — with genuinely different mechanisms — matters. A lineup of near-identical GLP-1 medicines risks being, in the editorialists’ framing, a set of “me too” options; agents that work through different pathways give clinicians more ways to reach the people a single mechanism misses.

The scale behind that argument is large. China alone accounts for the world’s biggest population living with overweight or obesity — on the order of 400 million people — and individuals of Chinese and South Asian descent tend to develop weight-related cardiometabolic complications at a lower body mass index than European populations. That is part of why testing new agents across different populations, not just in Western trials, matters for understanding how well they actually work.

Mazdutide and orforglipron sit at different points on that map. Mazdutide is a dual agonist, hitting the GLP-1 and glucagon receptors. Orforglipron is a GLP-1 agonist, like semaglutide, but delivered as a once-daily pill. Read together, the two trials are less about which drug wins and more about a field that is broadening — adding mechanisms and adding formulations at the same time.

What each trial showed

In GLORY-2, mazdutide was tested at 9 mg once weekly against placebo in 461 Chinese adults with obesity, on top of diet and exercise, for 60 weeks. Average body weight fell 16.65%, versus 1.50% on placebo, and the responder pattern was steep: 69.9% of the mazdutide group lost at least 10% of their body weight, 57.3% lost at least 15%, and 42.4% lost at least 20% — against 2.6% on placebo at that deepest threshold. Waist circumference, blood pressure, and cholesterol all improved. The catch was tolerability: gastrointestinal side effects were common, with vomiting reported in 53.1% of the mazdutide group, though most cases were mild to moderate and few people stopped. The full breakdown is in the mazdutide trial.

In ACHIEVE-5, orforglipron was tested differently — as a daily pill added to titrated insulin glargine in adults whose type 2 diabetes was still above target on insulin, many also on metformin or an SGLT2 inhibitor. Across doses, it lowered A1c by roughly 1.6 to 1.9 percentage points versus 0.8 on placebo, and up to about 70% of participants reached an A1c under 7% versus 25% on placebo. It also trimmed body weight by up to roughly 5%, and — the clinically important part — it did not raise the risk of significant low blood sugar, the thing insulin users worry about most when adding another drug. The details are in the orforglipron trial.

Oral vs injectable, one hormone vs two

Two axes separate these drugs, and both matter more than the headline percentages.

The first is delivery. Mazdutide is a weekly injection; orforglipron is a daily pill with no food or water restrictions. Almost every widely used GLP-1 medicine today is an injection, and the friction of shots is a real barrier to both starting and staying on treatment. A pill that holds up in a phase 3 trial shifts the access calculus in a way the raw numbers don’t capture.

The second is mechanism. Orforglipron acts on GLP-1 alone. Mazdutide adds a second target, the glucagon receptor — a different pairing than tirzepatide (Mounjaro), which combines GLP-1 with GIP. More targets can mean more effect, and sometimes a different side-effect profile; the heavier gastrointestinal burden in the mazdutide trial is consistent with what’s been seen for other dual glucagon/GLP-1 agents.

One caution worth stating plainly: these were separate trials, in different countries, populations, and durations, testing different things. You cannot line up mazdutide’s weight-loss percentage against orforglipron’s and declare a winner — there is no head-to-head trial, and cross-trial comparisons of this kind are unreliable. They are different tools, not ranked entries on one list.

What’s still unknown

For all the momentum, the open questions are substantial. Neither trial was long or large enough to settle long-term cardiovascular outcomes or durability, and weight tends to return after these drugs are stopped — the editorial notes that roughly half to more than half of lost weight is typically regained within a year of stopping a GLP-1, even with continued diet and lifestyle support. There is also a standing list of safety signals the field is still watching across this drug class — including pancreatitis, slowed stomach emptying, loss of muscle along with fat, and ophthalmic effects — though the editorial’s read is that the overall balance of benefit and risk still favors treatment.

Some of the reassurance is accumulating in real time. After orforglipron’s US approval for weight management, a required post-approval analysis reported that it did not increase the risk of major cardiovascular events — a meaningful data point, if not the same as proving long-term benefit. And the limiting factor outside any trial is rarely efficacy: high cost and uneven insurance coverage remain the practical barriers to who actually gets these medicines, and to whether they stay on them long enough to keep the result.

Step back from the percentages and the through-line is simple: the treatment of metabolic disease is gaining mechanisms and formulations at the same time. A dual-hormone injection that drives weight loss into the high teens, and an oral GLP-1 that improves blood sugar on top of insulin without more dangerous lows, are not really competitors. They are evidence that the same underlying problem can now be approached from more angles — which matters most for the people who don’t respond to, or can’t tolerate, any single one.

The counterweights are just as real. Mazdutide’s tolerability burden was heavy, and for both drugs the factors that decide real-world success are cost, coverage, and staying on treatment long enough to hold the benefit. For readers on the obesity–diabetes continuum, the right read is neither hype nor dismissal: the options are widening, the evidence is still maturing, and the next move is a conversation with a clinician, not a decision made from a headline.

Not medical advice. Educational summary of published research. Last reviewed Jun 15, 2026.