Mazdutide: Dosage & Administration
Part of the Mazdutide Complete Guide
Research Peptides
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Regulatory Status: China-First Development
Mazdutide (IBI362, also LY3305677) is a dual GLP-1 / glucagon receptor agonist co-developed by Eli Lilly and Innovent Biologics, with Phase 2 and Phase 3 development primarily through Innovent in China. The molecule was approved by China's NMPA in 2025 for weight management — making mazdutide one of the first GLP-1/glucagon co-agonists with regulatory approval anywhere in the world.[1]
Mazdutide is not FDA-approved in the United States. US Phase 3 trials are at earlier stages than the Chinese program. It is not on the July 2026 FDA Pharmacy Compounding Advisory Committee 503A bulks list agenda. Mazdutide sold in US research-peptide markets is unregulated and is not the clinical-grade molecule used in the Innovent / Lilly trials.
Phase 2 & Phase 3 Dosage Protocols
| Indication | Trial | Dose Range | Route / Frequency | Duration |
|---|---|---|---|---|
| Obesity | Phase 2 (Ji et al., Lancet 2023) | 3 / 4.5 / 6 mg | SC weekly | 24 weeks |
| Obesity | Phase 3 GLORY-1 | 4 / 6 mg | SC weekly | 48 weeks |
| Type 2 diabetes | Phase 2 | 3 / 4.5 / 6 mg | SC weekly | 16–20 weeks |
| Type 2 diabetes | Phase 3 DREAMS | 3 / 4 / 6 mg | SC weekly | 24 weeks |
The 4 mg and 6 mg weekly doses have emerged as the Phase 3 lead doses. Phase 3 GLORY-1 obesity trial in Chinese patients showed approximately 11.5% weight loss at the 6 mg dose over 48 weeks.[1] Phase 2 data established that doses below 3 mg/week are sub-therapeutic.
Dose Escalation Schedule
The Phase 3 obesity titration schedule:
| Weeks | Dose | Notes |
|---|---|---|
| Weeks 1–4 | 1.5 mg/week | Initial acclimation; sub-therapeutic |
| Weeks 5–8 | 3 mg/week | First therapeutic step |
| Weeks 9–12 | 4.5 mg/week | Intermediate maintenance |
| Weeks 13+ | 6 mg/week (target) | Phase 3 lead dose |
Total escalation: approximately 12 weeks to reach the 6 mg target. This is slower than semaglutide's titration because the glucagon component adds GI burden. If a step is not tolerated, hold at the current dose for an additional 2–4 weeks before retrying. The 4 mg dose is a reasonable maintenance step for patients who cannot reach 6 mg.
Administration
- Route: subcutaneous injection (clinical formulation is a pre-filled pen).
- Sites: abdomen (at least 5 cm from navel), thigh, or upper arm. Rotate sites weekly.
- Timing: any day of the week; same day each week for consistent intervals. Any time of day.
- Food: not strictly meal-dependent.
- Missed dose: if within 3 days of scheduled day, take as soon as possible; resume normal schedule. If > 3 days late, skip and take the next scheduled dose. Do not double-dose.
For SC injection technique, see the injection guide.
Drug-Interaction Timing
Mazdutide shares the gastric-emptying delay typical of GLP-1 family drugs. Key oral medication interactions:
- Oral contraceptives: absorption may be reduced. Consider backup contraception during titration.
- Levothyroxine: separate by ≥30 minutes; monitor TSH after starting.
- Warfarin: monitor INR more frequently during dose changes.
- Narrow-therapeutic-index drugs (digoxin, lithium, anticonvulsants): monitor levels.
- Insulin / sulfonylureas: reduce dose to avoid hypoglycemia in diabetic patients.
- Other GLP-1 family drugs (semaglutide, tirzepatide, retatrutide, survodutide, liraglutide): do not combine.
Duration & Continuous Use
Long-term continuous use is the anticipated maintenance pattern, consistent with the GLP-1 class. Phase 3 trials evaluate 24–48 week periods. Weight regain after discontinuation is expected. No cycling is required — mazdutide does not produce receptor tolerance the way some peptides do.
Storage
- Pre-filled pens: refrigerate at 2–8°C until first use.
- After first use: room temperature (up to 30°C) for the duration specified in pen instructions, typically 28–30 days.
- Do not freeze.
- Protect from light.
- Visual check: solution should be clear and colorless; discard if cloudy or particulate.
For broader storage rules, see the peptide storage guide.