Retatrutide (20mg)
Retatrutide is a triple GLP-1/GIP/glucagon agonist. The 20 mg vial significantly reduces the number of vials needed for maintenance doses of 8–12 mg/wk. Administered weekly.
Reviewed by the AllPeptides.eu Editorial Team·Last reviewed: 2026-06-16
Educational information. Not medical advice, and no efficacy claim is implied. Regulatory approval is not a use recommendation by AllPeptides.eu.
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Research monograph
See the full Retatrutide encyclopedia page with mechanism, evidence tier, related variants and research context.
How It Works
Triple GLP-1/GIP/glucagon agonist. Synergistic effects on appetite, energy expenditure, and glycemic control.
Quick Start
- Reconstitution: Add 2.0 mL of bacteriostatic water → 10.0 mg/mL.
- Weekly Range: 2–12 mg once weekly.
- Easy Dosing: At 10 mg/mL, 1 unit = 100 mcg.
- Storage: −20 °C / 2–8 °C after reconstitution.
Gradual Titration (2 mL = 10.0 mg/mL)
Route: Subcutaneously | Frequency: Once weekly
| Week | Dose | Units (per injection) |
|---|---|---|
| Weeks 1–4 | 2 mg | 20 Units (0.20 mL) |
| Weeks 5–8 | 4 mg | 40 Units (0.40 mL) |
| Weeks 9–12 | 6 mg | 60 Units (0.60 mL) |
| Weeks 13+ | 8 mg | 80 Units (0.80 mL) |
Studies report administration once weekly. The high concentration (10 mg/mL) keeps injection volumes small. All doses ≤12 mg can be drawn from a single vial. For Aggressive protocol: 2→4→8→12 mg.
Related compounds
Reconstitution Steps
- Aspirate 2.0 mL of bacteriostatic water.
- Inject slowly down the side of the vial.
- Swirl gently.
- Refrigerate at 2–8 °C.
Protocol Overview
- Goal: Up to 24% weight loss via triple agonism.
- Advantage: Fewer vials, small injection volumes.
Dosing Protocol
- Start: 2 mg/wk × 4 weeks.
- Escalation: 4→8→12 mg every 4 weeks.
- Maintenance: 8–12 mg/wk.
- Break between cycles: After completing the cycle, a washout period of 6–8 weeks is recommended. Retatrutide has a prolonged action — a longer washout period is required.
Washout & Cycle Restart
When can I restart?
After completing the cycle, a washout period of 6–8 weeks is recommended. Retatrutide has a prolonged action — a longer washout period is required.
Minimum wait period: 6 weeks
Storage Instructions
- Lyophilized: −20 °C.
- Reconstituted: 2–8 °C; use within 2–4 weeks.
Important Notes
- Gradual titration starting from 2 mg.
- Monitor for GI side effects.
Potential Benefits & Side Effects
Potential Benefits:
- Up to 24% body weight loss.
- HbA1c reductions of ~2%.
- Improvement in lipid markers.
Potential Side Effects:
- Gastrointestinal (GI): nausea (45–67%), diarrhea (30–45%), vomiting (15–25%).
- Decreased appetite (therapeutic, but risk of malnutrition).
- Injection site reactions.
- Constipation (10–20%).
- Abdominal pain.
- Rare: pancreatitis, cholelithiasis.
⚠️ Serious Warnings & Long-Term Risks
The following warnings are based on published literature, FDA labels, and post-marketing surveillance. They do not constitute medical advice. Consult a healthcare professional.
Potential thyroid C-cell risk
As a triple GLP-1/GIP/Glucagon agonist, the same class-effect warning as semaglutide/tirzepatide is expected.
📄 Phase 2 Trial — NEJM 2023References
- NEJM (2023) — Retatrutide for Obesity
View Source - The Lancet (2023) — Retatrutide in Type 2 Diabetes
View Source
Recommended Supplements
Vitamin B12 (Methylcobalamin)
Vitamin D3 + K2
Omega-3 Fish Oil (EPA/DHA)
Protein / Collagen
Fiber Supplement (Psyllium)
External Sources & Regulatory Status
Regulatory Approvals
Obesity / Type 2 diabetes
Obesity / Type 2 diabetes
Phase III clinical trials
Educational information. Not medical advice, and no efficacy claim is implied. Regulatory approval is not a use recommendation by AllPeptides.eu.
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