Retatrutide Dosage Schedule: Weekly Chart by Vial Size (10mg–60mg)

This is your quick-reference guide to retatrutide dosing. If you want the full clinical protocol with dose-hold decisions and side effect management, see our [complete titration guide](/guides/retatrutide-dosing-protocol-complete-titration-guide). This page focuses on the practical charts and calculators you need for weekly dosing. ## Retatrutide Standard Dosage Schedule The Phase 2 NEJM trial established this 20-week titration protocol, now widely adopted by prescribers: | Phase | Weeks | Weekly Dose | Purpose | |-------|-------|-------------|---------| | **Initiation** | 1–4 | 1 mg | GI acclimation, minimal weight loss expected | | **Low Dose** | 5–8 | 2 mg | Gradual receptor activation | | **Therapeutic Entry** | 9–12 | 4 mg | Meaningful weight loss begins (~17% in trials) | | **Therapeutic** | 13–16 | 8 mg | Accelerated weight loss (~22% in trials) | | **Maximum** | 17–20+ | 12 mg | Peak efficacy (~24.2% in trials) | > **Key point:** Not everyone needs 12mg. Many patients achieve their target weight at 4mg or 8mg. Discuss with your prescriber before each escalation. ## Syringe Dose Calculator by Vial Size Once reconstituted, your dose volume depends on the concentration (mg/mL). Here are the most common vial sizes: ### 10mg Vial + 1mL BAC Water (10mg/mL) | Dose | Volume | Syringe Units | Doses per Vial | |------|--------|---------------|----------------| | 1 mg | 0.10 mL | 10 units | 10 doses | | 2 mg | 0.20 mL | 20 units | 5 doses | | 4 mg | 0.40 mL | 40 units | 2.5 doses | ### 20mg Vial + 2mL BAC Water (10mg/mL) | Dose | Volume | Syringe Units | Doses per Vial | |------|--------|---------------|----------------| | 2 mg | 0.20 mL | 20 units | 10 doses | | 4 mg | 0.40 mL | 40 units | 5 doses | | 8 mg | 0.80 mL | 80 units | 2.5 doses | ### 30mg Vial + 3mL BAC Water (10mg/mL) | Dose | Volume | Syringe Units | Doses per Vial | |------|--------|---------------|----------------| | 4 mg | 0.40 mL | 40 units | 7.5 doses | | 8 mg | 0.80 mL | 80 units | 3.75 doses | | 12 mg | 1.20 mL | 120 units | 2.5 doses | ### 60mg Vial + 6mL BAC Water (10mg/mL) | Dose | Volume | Syringe Units | Doses per Vial | |------|--------|---------------|----------------| | 8 mg | 0.80 mL | 80 units | 7.5 doses | | 12 mg | 1.20 mL | 120 units | 5 doses | ## Reconstitution Quick Reference 1. **Gather supplies:** Vial, bacteriostatic water (BAC), alcohol swabs, insulin syringe 2. **Draw BAC water:** Use the table above for your vial size 3. **Inject slowly:** Aim the needle at the vial wall, push gently — do NOT spray directly onto the powder 4. **Swirl gently:** Roll the vial between your palms for 30–60 seconds until fully dissolved 5. **Inspect:** Solution should be clear and colorless; discard if cloudy or discolored 6. **Store:** Refrigerate at 2–8°C (36–46°F); use within 28 days > **Never shake the vial.** Aggressive shaking can denature the peptide and reduce potency. ## Monthly Vial Planning Chart Planning how many vials you need per month of treatment: | Dose Phase | Monthly Dose | 10mg Vials | 20mg Vials | 30mg Vials | 60mg Vials | |------------|-------------|------------|------------|------------|------------| | 1 mg (wk 1-4) | 4 mg/mo | 1 vial | — | — | — | | 2 mg (wk 5-8) | 8 mg/mo | 1 vial | 1 vial | — | — | | 4 mg (wk 9-12) | 16 mg/mo | 2 vials | 1 vial | 1 vial | — | | 8 mg (wk 13-16) | 32 mg/mo | — | 2 vials | 1-2 vials | 1 vial | | 12 mg (wk 17+) | 48 mg/mo | — | — | 2 vials | 1 vial | ## Injection Best Practices **Where to inject:** Rotate between abdomen (2 inches from navel), front of thighs, and back of upper arms. Never inject in the same spot twice in a row. **When to inject:** Same day each week. Most users prefer evenings — mild nausea (if any) occurs during sleep. **Injection angle:** 90° for most patients with an insulin syringe. 45° angle for very lean patients with less subcutaneous fat. **Post-injection:** Apply gentle pressure with an alcohol swab. Do not rub. Minor redness at the injection site is normal and resolves within hours. ## When to Hold or Adjust Your Dose **Hold at current dose (do not escalate) if:** - Losing 1%+ body weight per week at current dose - Persistent nausea or GI symptoms that haven't resolved - HbA1c dropping rapidly (risk of hypoglycemia in diabetic patients) **Return to previous dose if:** - Vomiting more than 2 days per week - Unable to maintain adequate hydration or caloric intake - Significant impact on daily activities **Contact your prescriber immediately if:** - Severe abdominal pain (possible pancreatitis) - Signs of thyroid changes (lump in neck, difficulty swallowing) - Allergic reaction (rash, swelling, difficulty breathing) ## Cost-Per-Dose Breakdown Understanding what each injection costs helps with treatment planning: | Vial Size | Approx. Cost | Cost at 4mg/wk | Cost at 8mg/wk | Cost at 12mg/wk | |-----------|-------------|-----------------|-----------------|------------------| | 10mg | $80–120 | $32–48/dose | N/A | N/A | | 20mg | $140–200 | $28–40/dose | $56–80/dose | N/A | | 30mg | $200–280 | $27–37/dose | $53–75/dose | $80–112/dose | | 60mg | $350–480 | — | $47–64/dose | $70–96/dose | > **Bulk savings:** Larger vials offer 15–25% lower cost per milligram. For maintenance dosing at 8mg or 12mg, 60mg vials are most cost-effective. [See our full cost guide](/guides/retatrutide-cost-price-guide-2026) for pharmacy comparisons. ## Printable Weekly Tracker Use this template to track your weekly injections: **Week ___ | Date: ________ | Dose: ___mg | Vial #: ___ | Injection Site: ________** - [ ] Reconstitution date: ________ - [ ] Syringe units drawn: ________ - [ ] Time of injection: ________ - [ ] Side effects noted: ________ - [ ] Weight this week: ________ *Tip: Take a photo of your weekly tracker and share with your prescriber at each follow-up.* ## Related Resources - [Retatrutide Dosing Protocol: Complete Titration Guide](/guides/retatrutide-dosing-protocol-complete-titration-guide) — Full clinical protocol with dose-hold decisions - [How to Reconstitute Retatrutide](/guides/how-to-reconstitute-retatrutide-mixing-guide) — Step-by-step mixing instructions - [Retatrutide Cost & Price Guide 2026](/guides/retatrutide-cost-price-guide-2026) — Pharmacy pricing comparison - [Retatrutide Side Effects Guide](/guides/retatrutide-side-effects-management-guide) — Dose-specific side effect management ## References - [Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial](https://www.nejm.org/doi/full/10.1056/NEJMoa2301972). *New England Journal of Medicine*, 2023. - [Retatrutide Phase 2 Trial: Supplementary Appendix (Dosing Protocol)](https://www.nejm.org/doi/suppl/10.1056/NEJMoa2301972/suppl_file/nejmoa2301972_appendix.pdf). *New England Journal of Medicine*, 2023. - [Pharmacokinetics of Retatrutide (LY3437943) in Healthy Volunteers](https://pubmed.ncbi.nlm.nih.gov/?term=Pharmacokinetics+of+Retatrutide+(LY3437943)+in+Healthy). *Clinical Pharmacology & Therapeutics*, 2023.