Retatrutide Dosing Protocol: 20 mg Vial — Week-by-Week Titration & Supplies
Quickstart highlights
The 12 mg dose of retatrutide produced 24.2% mean body weight reduction at 48 weeks (NCT04881760), superior to all other approved or investigational anti-obesity agents in comparable trial designs.
- Concentration: 10 mg/mL (20 mg vial + 2 mL bacteriostatic water).
- At 10 mg/mL: 1 mg = 10 units, 4 mg = 40 units, 8 mg = 80 units, 12 mg = 120 units.
- Phase 2 trial: 12 mg dose achieved 24.2% mean weight reduction — highest ever reported for anti-obesity pharmacotherapy.
- One 20 mg vial provides 2.5 doses at 8 mg or ~1.67 doses at 12 mg maintenance.
- Double-check units — concentration here (10 mg/mL) is double the standard 5 mg/mL vials.
Dosing table
For educational reference only. Your prescribing provider may adjust doses based on your clinical profile and response.
| Week | Dose (µg) | Units | Frequency | Notes |
|---|---|---|---|---|
| 1-4 | 1000 | 10 | Once weekly | 1 mg — 10 units at 10 mg/mL; 20 starting doses per vial |
| 5-8 | 2000 | 20 | Once weekly | 2 mg — 20 units |
| 9-12 | 4000 | 40 | Once weekly | 4 mg — 40 units; 5 doses per vial |
| 13-16 | 8000 | 80 | Once weekly | 8 mg maintenance — 80 units; 2.5 doses per vial |
| 17+ | 12000 | 120 | Once weekly | 12 mg maximum — 120 units; ~1.67 doses per vial |
Your free Retatrutide tracker
- Dose reminders
- Injection logging
- Cycle progress
Reconstitution steps
- Draw 2 mL bacteriostatic water; inject slowly down the vial wall.
- Swirl gently until powder dissolves; do not shake.
- Final concentration: 10 mg/mL (20 mg / 2 mL). Note: double the concentration of 5 mg/mL vials — verify units.
- Label with date and 10 mg/mL; refrigerate at 2–8 °C.
Supplies needed
12-week plan
- 1 vial
- 12 syringes
- 2 mL bac water
- 12 alcohol swabs
20-week plan
- 2 vials
- 20 syringes
- 4 mL bac water
- 20 alcohol swabs
Protocol overview & cycle notes
Support advanced retatrutide dosing up to the 12 mg maximum studied in Phase 2 trials, using the 20 mg high-concentration vial for efficient maintenance dosing at 8–12 mg weekly.
Cycle length: 20 weeks on.
Off-cycle: 8–12 weeks off between cycles.
Storage & handling
Injection & tracking tips
- CRITICAL: At 10 mg/mL, 1 unit = 100 µg. This is half the units needed compared to 5 mg/mL vials. Do not use your 5 mg/mL unit chart for this vial.
- The 20 mg vial is most economical for patients at 8–12 mg maintenance — each vial provides 2–2.5 weekly doses.
- Use a 1 mL U-100 syringe for doses ≤10 mg (100 units); use a 3 mL syringe for the 12 mg dose (120 units = 1.2 mL).
Tracking
Logging helps you and your provider spot patterns and adjust dose or timing.
- Monitor body weight weekly; expect slowdown in rate of loss after reaching maintenance dose.
- Track liver enzyme labs (ALT/AST) monthly — glucagon agonism improves hepatic steatosis.
- Record energy, hunger, and satiety scores daily for the first 4 weeks at each new dose level.
How this works & references
Frequently asked questions
Why use 10 mg/mL instead of 5 mg/mL for the 20 mg vial?
Is 12 mg the maximum retatrutide dose?
How does 10 mg/mL affect my unit calculation?
What are the most common side effects at 8–12 mg?
When is the best time to inject retatrutide?
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