Retatrutide Dosing Protocol: 30 mg Vial — Maintenance Dosing & Supplies
Quickstart highlights
Retatrutide's Phase 2 data (NCT04881760) demonstrated dose-dependent weight loss: 12 mg = 24.2%, 8 mg ≈ 22%, 4 mg ≈ 17.5% at 48 weeks.
- Concentration: 10 mg/mL (30 mg vial + 3 mL bacteriostatic water).
- At 10 mg/mL: 8 mg = 80 units (0.8 mL), 12 mg = 120 units (1.2 mL).
- One 30 mg vial provides ~3.75 doses at 8 mg/week or ~2.5 doses at 12 mg/week.
- Most efficient vial size for patients stabilized at 8–12 mg weekly maintenance.
- Refrigerate; use within 28 days of reconstitution.
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; 30 mg vial provides 30 starting doses |
| 5-8 | 2000 | 20 | Once weekly | 2 mg — 20 units |
| 9-12 | 4000 | 40 | Once weekly | 4 mg — 40 units; 7.5 doses per vial |
| 13-16 | 8000 | 80 | Once weekly | 8 mg maintenance — 80 units; 3.75 doses per vial |
| 17+ | 12000 | 120 | Once weekly | 12 mg maximum — 120 units; 2.5 doses per vial |
Retatrutide Dosage Calculator
This free peptide calculator shows the exact insulin-syringe units to draw for Retatrutide. Enter your vial size, bacteriostatic water and target dose — it’s pre-loaded with common Retatrutide reconstitution defaults, so you can adjust any field to match your own vial.
Your free Retatrutide tracker
- Dose reminders
- Injection logging
- Cycle progress
Reconstitution steps
- Draw 3 mL bacteriostatic water; inject slowly down the vial wall.
- Swirl gently until lyophilized powder is fully dissolved.
- Final concentration: 10 mg/mL (30 mg / 3 mL). Label with date and concentration.
- Refrigerate at 2–8 °C; use within 28 days.
Supplies needed
12-week plan
- 1 vial
- 12 syringes
- 3 mL bac water
- 12 alcohol swabs
20-week plan
- 2 vials
- 20 syringes
- 6 mL bac water
- 20 alcohol swabs
Protocol overview & cycle notes
Provide an extended multi-week supply of retatrutide from a single 30 mg vial for patients established on 8–12 mg maintenance, minimizing reconstitution events and optimizing cost-efficiency.
Cycle length: 20 weeks on.
Off-cycle: 8–12 weeks off between cycles. Monitor for weight regain and metabolic parameter changes.
Storage & handling
Injection & tracking tips
- The 30 mg vial is the most efficient option for maintenance dosing at 8–12 mg weekly — fewer reconstitutions, lower per-dose handling burden.
- At 10 mg/mL: 8 mg = 80 units (0.8 mL), 12 mg = 120 units (1.2 mL). Use a 1 mL syringe for 8 mg; use a 3 mL syringe for 12 mg.
- Mark the vial with each draw date and remaining volume to track usage accurately.
Tracking
Logging helps you and your provider spot patterns and adjust dose or timing.
- Record body weight and BMI monthly at maintenance dosing.
- Track percentage body fat via DEXA or InBody every 8 weeks if possible.
- Log fasting glucose, insulin, and HOMA-IR quarterly to monitor insulin sensitivity.
How this works & references
Sources
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. Jastreboff AM et al. — N Engl J Med — 2023
- TRIUMPH Phase 3 (NCT05668520) — ongoing Phase 3 efficacy and safety study
- Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. Rosenstock J et al. — Lancet — 2023
- Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial. Coskun T et al. — Lancet Diabetes Endocrinol — 2025
Frequently asked questions
How many weeks does a 30 mg vial last at 8 mg/week?
Is the 30 mg vial the best choice for long-term maintenance?
Can I start retatrutide directly at 8 mg using this vial?
What happens when I stop retatrutide?
How does retatrutide affect liver enzymes?
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View protocolThis content is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider before starting any peptide therapy. Dosing and protocols may vary by formulation and prescriber.