Mazdutide

Mazdutide (IBI362, LY3305677) is a once-weekly injected peptide built on oxyntomodulin that activates the GLP-1 and glucagon receptors. Lilly and Innovent develop it, and Innovent sells it in China as Xinermei.

No. In the US it is investigational: Lilly has run phase 2 trials there. FDA warning letters in 2024 and 2026 called mazdutide sold online an unapproved new drug. China approved it in June 2025 for weight management and in September 2025 for type 2 diabetes.

China's type 2 diabetes label starts at 2 mg weekly for 4 weeks, then 4 mg, with 6 mg allowed after at least 4 more weeks; maintenance is 4 or 6 mg. A news repost of the weight-management label gives the same steps. A phase 2 trial used the same 2, 4, 6 mg steps, each 4 weeks long. Higher-dose trials went to 9 mg in China and 10 or 16 mg in the US.

Phase 3 trials in China used 4 and 6 mg (GLORY-1, diabetes trials) and 9 mg (GLORY-2). Phase 2 trials tested 3 to 6 mg and 9 mg in China, and 3 to 6 mg, 10 mg and 16 mg in the US. All were once-weekly injections under the skin.

In GLORY-1, average weight change at 48 weeks was -11.00% on 4 mg and -14.01% on 6 mg, vs +0.30% on placebo. In GLORY-2, 9 mg gave 16.65% at 60 weeks vs 1.50%. In the US phase 2 trial, 16 mg gave 18.1% at just 32 weeks.

Yes, and it costs more side effects. GLORY-2 at 9 mg reached 16.65% weight loss at 60 weeks, but vomiting hit 53.1% and nausea 46.9%. In the US trial, 16 mg gave the most loss and also the most dropouts (20%).

Vomiting, nausea, diarrhea and lower appetite, mostly mild to moderate and worst during the dose climb. Heart rate rises a few beats per minute early on. Rates climb with dose: at 6 mg in phase 2, nausea was 41.0%; at 9 mg in GLORY-2, it was 46.9%.

One guide uses 3 mL for about 3.33 mg/mL, where each U-100 unit is about 33 mcg. Another common choice is 2 mL for 5 mg/mL, where each unit is 50 mcg. The approved Chinese pen needs no mixing.

In a phase 1b trial in Chinese adults, the half-life ranged from 6.3 to 16.8 days after the first dose, with peak levels at a median of 72 hours. That long tail is why it is dosed once a week.

Retatrutide hits three receptors (GLP-1, GIP and glucagon); mazdutide hits two. Mazdutide is approved in China; retatrutide is approved nowhere. No trial compares them, though r/Peptides and r/PeptideGuide ask about it often.

Both pair GLP-1 with glucagon. Mazdutide is an oxyntomodulin analog with approval in China; survodutide is a glucagon analog still in phase 3 worldwide. No head-to-head trial exists.

As reported from the label: unopened pens go in the fridge at 2 to 8 C and must never freeze. After first use a pen can stay at room temperature for up to 30 days. The multi-dose pen approved in 2026 keeps 12 weeks in the fridge after first use.

As reported from the label: if 5 days or fewer have passed, inject as soon as you can and carry on. If more than 5 days have passed, skip it and take the next dose on schedule. Keep doses at least 5 days apart.

r/Mazdutide is where the dose logs are. Most posters add it to tirzepatide after a stall, start at 1 or 2 mg and report holding 1.5 to 5 mg; one had heavy diarrhea at 6 mg and stepped back to 4. On r/Peptides people call it retatrutide's cousin, ask whether to stack it with tirzepatide and share trial news. One poster reported a mixed vial starting to gel.

It is not named on the WADA 2026 list. The S0 class only covers drugs with no approval from any health authority, and China has approved mazdutide, so S0 does not apply.