Mazdutide: The GLP-1/Glucagon Dual Agonist to Watch

Mazdutide is an investigational once-weekly injectable that switches on two hormone receptors at the same time — the GLP-1 receptor and the glucagon receptor — making it the first dual GLP-1/glucagon receptor agonist approved anywhere for weight management. China's National Medical Products Administration (NMPA) approved it in June 2025 for chronic weight management, and again in September 2025 for type 2 diabetes. It is not FDA-approved, and it is not sold, available, or prescribable in the United States. In phase 3 trials of Chinese adults, the higher doses studied produced roughly 14% to 19% average weight loss over 48 to 60 weeks, alongside unusually large drops in liver fat.

This is a plain-language reference page — not a diagnosis, and not a prescription. For the wider picture, start with our plain-English GLP-1 explainer and the full GLP-1 medication guide, then compare the other next-generation candidates: retatrutide (a triple agonist), survodutide (another GLP-1/glucagon dual agonist), and CagriSema (amylin plus GLP-1). You can also browse our drug reference library, the weight & metabolism hub, and the GLP-1 pipeline timeline.

What mazdutide is — and why its mechanism is different

Mazdutide (development codes IBI362 and LY3305677) is a once-weekly subcutaneous peptide. It was discovered at Eli Lilly and licensed to Innovent Biologics, which develops and commercializes it in China; Lilly keeps the rights everywhere else. What makes it stand out is not that it is stronger than existing drugs, but that it works through a different pair of receptors.

Most weight-loss medicines women already know act on the GLP-1 system alone (semaglutide, sold as Ozempic and Wegovy) or on GLP-1 plus GIP (tirzepatide, sold as Mounjaro and Zepbound). Mazdutide keeps the GLP-1 arm — which curbs appetite, slows stomach emptying, and prompts insulin release to lower blood sugar — but pairs it with glucagon receptor activation. Glucagon is best known for raising blood sugar, so on its own it would work against a diabetes drug. Combining it with GLP-1 offsets that, and the glucagon signal is thought to add two things a pure GLP-1 drug does not: a possible bump in energy expenditure and a direct push on the liver to burn stored fat.

Where mazdutide is approved — and where it is not

Geography is the single most important fact about this drug, and it is where a lot of online writing gets sloppy. Mazdutide is approved and marketed in mainland China only. The NMPA cleared it on 27 June 2025 for adults with a body-mass index of 28 or higher, or 24 or higher with a weight-related health condition, and on 19 September 2025 for blood-sugar control in type 2 diabetes. Where it is approved, it is a prescription medicine that a clinician starts and titrates — not something a person doses on their own.

In the United States it is a different story: mazdutide is investigational. It has no FDA approval, no European approval, and no legal route to human use here. Eli Lilly's US clinical program is at an earlier stage than the Chinese one, so a US decision is still years away rather than months. Practically, that means there is no legitimate way to buy, be prescribed, or safely self-source mazdutide in America. Any "mazdutide" offered online or through a compounding channel in the US is outside the approved supply chain, is not the studied product, and carries unknown purity, dose, and safety. If you are weighing real options today, the approved GLP-1 medicines — reviewed in our tirzepatide guide and semaglutide drug page — are the ones a prescriber can actually work with.

What the phase 3 trials actually showed

The headline evidence comes from the GLORY program in Chinese adults. GLORY-1, published in the New England Journal of Medicine in May 2025, randomized 610 adults with obesity or overweight-plus-a-comorbidity to two doses of mazdutide (4 mg or 6 mg once weekly — the amounts tested in the trial, not a recommended dose) or placebo for 48 weeks. At week 48, average body weight fell about 12% on the lower dose and roughly 14.8% on the higher dose, versus a slight change with placebo. Just over half of the higher-dose group lost at least 15% of their body weight, compared with about 2% on placebo. Notably, dropout from side effects was very low — a tolerability signal researchers flagged as a strength.

GLORY-2 tested a higher dose in 462 adults with more severe obesity (average BMI around 34) over 60 weeks. Average weight loss reached about 18.6%, and among participants without diabetes it was roughly 20% — with about 44% of the treated group losing at least a fifth of their body weight. The trial also improved waist circumference, blood pressure, triglycerides, LDL and non-HDL cholesterol, and uric acid. A separate head-to-head phase 3 study (GLORY-3) is comparing mazdutide directly against semaglutide in people with obesity and fatty liver, which will give the first apples-to-apples read. For context on how these percentages translate to real-world expectations, our weight-loss projector models GLP-1 trajectories.

The glucagon angle: liver fat and energy expenditure

The most distinctive part of mazdutide's story is the liver. Glucagon receptors sit on liver cells, and switching them on drives the liver to oxidize its own stored fat. In a phase 2 trial of adults with obesity and elevated liver fat, mazdutide cut liver fat content by as much as roughly 69%, and steatosis (fatty liver) resolved in more than 60–70% of participants at the higher doses — compared with about 13% on placebo. That is a magnitude of liver-fat improvement that GLP-1-only drugs generally do not reach, and it is a direct consequence of the glucagon component rather than weight loss alone.

The proposed energy-expenditure benefit — the idea that glucagon nudges the body to burn more calories at rest — is biologically plausible and supported by mechanistic research, but in humans the clearest, best-measured effects so far are the weight loss and the liver-fat reduction. It is honest to describe the metabolic-rate piece as a promising hypothesis rather than a proven, quantified advantage. If fatty liver is your concern, our explainer on GLP-1 drugs and fatty liver covers what the approved options can and cannot do.

What mazdutide could mean for women in midlife

VidaBeacon's lens is women's midlife and hormone health, so here is the honest connection — and its limits. The GLORY trials enrolled Chinese adults of both sexes and were not designed to answer questions specific to women, menopause, or PCOS. There are no menopause-specific or women-specific mazdutide results to cite yet.

Why the drug class still matters to this audience: the metabolic shifts of perimenopause and menopause tend to push fat toward the abdomen and into the liver, and metabolic-dysfunction-associated steatotic liver disease (MASLD) becomes markedly more common after the menopausal transition. A therapy whose signature effect is visceral and liver-fat reduction is, in principle, well matched to that biology. If you are navigating menopause weight gain or midlife belly fat now, the practical takeaway is not "wait for mazdutide" — it is to work with a clinician on the GLP-1 options already available, plus muscle-protecting strength work, since any rapid weight loss can cost lean mass.

One contraception note, because it is often confused: among the approved incretin drugs, tirzepatide can temporarily lower the effectiveness of oral birth control, so its label advises a backup method after starting or increasing the dose; semaglutide is not known to do this. Mazdutide has no established contraceptive-interaction data because it is not approved here — another reason it belongs in the "watch, don't act" column for now. See GLP-1 drugs and birth control for the approved-drug details.

What we still don't know

Several gaps keep mazdutide firmly in the "promising, not proven for you" category. All pivotal efficacy data come from Chinese populations, so how the results generalize to more diverse groups is still being tested. There are no published long-term cardiovascular-outcome trials — the studies that ultimately show whether a metabolic drug prevents heart attacks and strokes, not just moves the scale. Because glucagon raises blood sugar, its long-term effect on glucose control at scale needs continued monitoring, even though the GLP-1 component offset it in trials. And the US regulatory timeline remains years out. For a sense of how these candidates tend to move from trial to pharmacy, see our GLP-1 timeline and the broader look at peptides marketed for weight loss.

When to talk to a doctor

Because mazdutide is not available in the US, the useful conversation is not "can I get it" but "what are my real, evidence-based options." Talk with a clinician — a primary-care doctor, an obesity-medicine specialist, or a menopause-informed provider — if excess weight, waist circumference, or a fatty-liver diagnosis is affecting your health, and especially if you have type 2 diabetes, high blood pressure, or high cholesterol alongside it. Obesity is a chronic, relapsing condition, not a willpower problem, and it is managed over years rather than cured. Our GLP-1 eligibility checker can help you frame that discussion. Do not buy or use any investigational or grey-market "mazdutide"; if a product is offered outside a licensed pharmacy, treat that as a red flag, not an opportunity.