The short answer
Both are weekly dual agonists built around the GLP-1 receptor, and the second target differs: glucagon for mazdutide, GIP for tirzepatide. Tirzepatide is FDA-approved, as Mounjaro and Zepbound; mazdutide, from Innovent and Eli Lilly, was approved in China in 2025 and isn’t FDA-approved. In its phase 3 GLORY-1 trial, people on mazdutide lost about 11% (4 mg) and 14% (6 mg) of their body weight at 48 weeks.
Side by side
| Compared | Mazdutide | Tirzepatide |
|---|---|---|
| Category | Metabolic & GLP-1 | Metabolic & GLP-1 |
| Also known as | IBI362, LY3305677, Xinermei | Mounjaro, Zepbound, LY3298176 |
| What it is | A once-weekly GLP-1 and glucagon dual agonist from Innovent and Eli Lilly, approved in China in 2025 for weight management (as Xinermei) and type 2 diabetes; it is not FDA-approved. | The first dual GIP/GLP-1 receptor agonist: it activates two gut-hormone pathways at once, and in a head-to-head trial it produced more weight loss than semaglutide (20.2% vs 13.7% at 72 weeks). |
| How it works | Once-weekly GLP-1 and glucagon receptor dual agonist built on oxyntomodulin, a gut hormone that acts on both receptors, with a C20 fatty-acid side chain that stretches its half-life to about 10 days. The GLP-1 arm curbs appetite; the glucagon arm adds energy expenditure (shown in mice). Developed by Innovent with Eli Lilly and approved in China in 2025 for weight management and type 2 diabetes. Its label steps the dose up every 4 weeks from 2 mg, and GI side effects come mostly during those step-ups. | Dual GIP/GLP-1 receptor agonist. Significantly reduces body weight through appetite suppression, slowed gastric emptying, and improved insulin sensitivity. Approved for T2DM and obesity management. |
| Commonly reported | Strong appetite suppression and GI side effects after each step-up, much as with other weekly GLP-1s; user reports from outside China are still few. | Very strong appetite suppression and meals ending early, with nausea or tiredness for a day or two after the injection, mostly after dose increases. FDA-approved for diabetes (Mounjaro) and for weight management and sleep apnea (Zepbound). |
| Studied range | Research range: 2–6 mg, starting dose 2 mg. Studied in research — not a recommendation. | FDA label: 2.5–15 mg, starting dose 2.5 mg. |
| How often | Weekly | Weekly |
| Half-life | ~10 days (Chinese label: the mean in people with obesity or overweight; about 8 days in type 2 diabetes) | ~5 days (FDA label) |
| Route | SubQ injection | SubQ injection |
| Typical run | Used continuously, once weekly, in its trials and label. Per the label, a dose 1 to 3 weeks late (2 to 4 weeks since the last one) restarts one dose step lower, and more than 3 weeks late restarts the 2 mg step. No trial has tested stopping it. | FDA-approved for ongoing use. Titrate slowly upward. Community maintains on minimum effective dose. |
| Evidence | Established: clinical trials or FDA-approved use exists | Established: clinical trials or FDA-approved use exists |
| Common side effects | Nausea, diarrhea, vomiting, abdominal bloating, abdominal pain, injection site reaction, dizziness, acid reflux | Nausea, diarrhea, vomiting, constipation, abdominal pain, decreased appetite, fatigue |
- Category
- MazdutideMetabolic & GLP-1
- TirzepatideMetabolic & GLP-1
- Also known as
- MazdutideIBI362, LY3305677, Xinermei
- TirzepatideMounjaro, Zepbound, LY3298176
- What it is
- MazdutideA once-weekly GLP-1 and glucagon dual agonist from Innovent and Eli Lilly, approved in China in 2025 for weight management (as Xinermei) and type 2 diabetes; it is not FDA-approved.
- TirzepatideThe first dual GIP/GLP-1 receptor agonist: it activates two gut-hormone pathways at once, and in a head-to-head trial it produced more weight loss than semaglutide (20.2% vs 13.7% at 72 weeks).
- How it works
- MazdutideOnce-weekly GLP-1 and glucagon receptor dual agonist built on oxyntomodulin, a gut hormone that acts on both receptors, with a C20 fatty-acid side chain that stretches its half-life to about 10 days. The GLP-1 arm curbs appetite; the glucagon arm adds energy expenditure (shown in mice). Developed by Innovent with Eli Lilly and approved in China in 2025 for weight management and type 2 diabetes. Its label steps the dose up every 4 weeks from 2 mg, and GI side effects come mostly during those step-ups.
- TirzepatideDual GIP/GLP-1 receptor agonist. Significantly reduces body weight through appetite suppression, slowed gastric emptying, and improved insulin sensitivity. Approved for T2DM and obesity management.
- Commonly reported
- MazdutideStrong appetite suppression and GI side effects after each step-up, much as with other weekly GLP-1s; user reports from outside China are still few.
- TirzepatideVery strong appetite suppression and meals ending early, with nausea or tiredness for a day or two after the injection, mostly after dose increases. FDA-approved for diabetes (Mounjaro) and for weight management and sleep apnea (Zepbound).
- Studied range
- MazdutideResearch range: 2–6 mg, starting dose 2 mg. Studied in research — not a recommendation.
- TirzepatideFDA label: 2.5–15 mg, starting dose 2.5 mg.
- How often
- MazdutideWeekly
- TirzepatideWeekly
- Half-life
- Mazdutide~10 days (Chinese label: the mean in people with obesity or overweight; about 8 days in type 2 diabetes)
- Tirzepatide~5 days (FDA label)
- Route
- MazdutideSubQ injection
- TirzepatideSubQ injection
- Typical run
- MazdutideUsed continuously, once weekly, in its trials and label. Per the label, a dose 1 to 3 weeks late (2 to 4 weeks since the last one) restarts one dose step lower, and more than 3 weeks late restarts the 2 mg step. No trial has tested stopping it.
- TirzepatideFDA-approved for ongoing use. Titrate slowly upward. Community maintains on minimum effective dose.
- Evidence
- MazdutideEstablished: clinical trials or FDA-approved use exists
- TirzepatideEstablished: clinical trials or FDA-approved use exists
- Common side effects
- MazdutideNausea, diarrhea, vomiting, abdominal bloating, abdominal pain, injection site reaction, dizziness, acid reflux
- TirzepatideNausea, diarrhea, vomiting, constipation, abdominal pain, decreased appetite, fatigue
Typical run: Community practice — opinions vary. Not a clinical recommendation.
Week by week
Each entry’s cards by day window, as the compound pages show them. Day 1 is the day you start it.
Mazdutide
- Day 1–28 · 2 mg Appetite first, scale later
- Day 29–56 · 4 mg A maintenance dose, not just a step
- Day 57–224 · 4 mg Holding at 4 mg
- Day 57–224 · 6 mg The top labelled dose
- Day 225–336 Weeks 32 to 48: still moving, more slowly
- Day 337+ A maintenance medication, not a course
Tirzepatide
- Day 1–28 · 2.5 mg Getting your gut acclimated
- Day 29–56 · 5 mg First therapeutic dose — weight drops
- Day 57–112 · 7.5 mg Dual agonism in full effect
- Day 113–168 · 12.5 mg Max titration reached
- Day 169–504 Weeks 24 to 72: where most people plateau
- Day 365+ A maintenance medication, not a course
Questions people ask
How long do mazdutide and tirzepatide last?
The half-life of mazdutide is ~10 days (Chinese label: the mean in people with obesity or overweight; about 8 days in type 2 diabetes). The half-life of tirzepatide is ~5 days (FDA label).
How often are mazdutide and tirzepatide taken?
Mazdutide: weekly. Route: SubQ injection. Tirzepatide: weekly. Route: SubQ injection.
How are mazdutide and tirzepatide dosed in research?
The research range for mazdutide is 2–6 mg, with a 2 mg starting dose. Studied in research — not a recommendation. The FDA label range for tirzepatide is 2.5–15 mg, with a 2.5 mg starting dose.
What are the common side effects of mazdutide and tirzepatide?
For mazdutide, the library lists: nausea, diarrhea, vomiting, abdominal bloating, abdominal pain, injection site reaction, dizziness, acid reflux. For tirzepatide: nausea, diarrhea, vomiting, constipation, abdominal pain, decreased appetite, fatigue.
Each one in full
PepVault for iPhone
Track either one in PepVault
Log every dose of mazdutide or tirzepatide, with reminders on your schedule. 7 days free on the yearly plan for new subscribers.
