Dosage protocol · Experimental Research
Retatrutide 5 mg
Typical weekly range: 2–8 mg once weekly (gradual escalation over 8–12 weeks).
- Reconstitute: Add 1.0 mL bacteriostatic water → ~5.0 mg/mL concentration.
- Typical weekly range: 2–8 mg once weekly (gradual escalation over 8–12 weeks).
- Easy measuring: At 5.0 mg/mL, 1 unit = 0.01 mL ≈ 50 mcg on a U-100 insulin syringe.
- Storage: Lyophilized: freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F) for up to 4 weeks.
BAC water1.0mL
Concentration5.0mg/mL
Reconstitution
Retatrutide dosage chart
Retatrutide dosage chart · 1
| Phase | Week | Draw | Vials Needed |
|---|---|---|---|
| Weeks 1–4 | 2 mg (2000 mcg) | 40 units0.40 mL | 1 vial per dose |
| Weeks 5–8 | 4 mg (4000 mcg) | 80 units0.80 mL | 1 vial per dose |
| Weeks 9–12 | 6 mg (6000 mcg) | 120 units1.20 mL | 2 vials per dose** |
| Weeks 13+ | 8 mg (8000 mcg) | 160 units1.60 mL | 2 vials per dose** |
Retatrutide dosage chart · 2
| Phase | Week | Draw | Vials Needed |
|---|---|---|---|
| Weeks 1–4 | 2 mg (2000 mcg) | 40 units0.40 mL | 1 vial per dose |
| Weeks 5–8 | 4 mg (4000 mcg) | 80 units0.80 mL | 1 vial per dose |
| Weeks 9–12 | 8 mg (8000 mcg) | 160 units1.60 mL | 2 vials per dose** |
| Weeks 13+ | 12 mg (12000 mcg) | 240 units2.40 mL | 3 vials per dose*** |
How much to draw
The Draw column shows exactly where to stop on a U-100 insulin syringe. Different vial size or dose? The calculator below recomputes it live.
Supplies needed
Supplies needed
Peptide vial
The lyophilized compound
Bacteriostatic water
For reconstitution
U-100 insulin syringes
One per injection
Alcohol swabs
Stopper + site each time
How it works
Retatrutide, also known by its development code LY3437943, is an investigational peptide-class "triple agonist" designed to activate three separate metabolic hormone receptors at once: GIP, GLP-1, and glucagon.[1] Eli Lilly is developing it for obesity, type 2 diabetes, and related metabolic conditions, but it is not an FDA-approved drug and has no approved prescription product on the market.
Retatrutide is often discussed alongside tirzepatide, a dual GIP/GLP-1 agonist, and semaglutide, a GLP-1-only agonist. Unlike those two, retatrutide remains in Phase 3 clinical trials rather than approved labeling, and its results should be read as investigational until regulators complete their review.[2]
Benefits & side effects
Retatrutide has produced some of the largest weight-loss figures reported in peptide-based metabolic trials to date. In a Phase 2 obesity trial, participants on the highest doses lost an average of roughly 22–24% of body weight at 48 weeks.[4] Eli Lilly's 2026 Phase 3 TRIUMPH-1 topline results reported an average reduction of about 28% of body weight at 80 weeks in the highest-dose group — larger than typical figures for currently approved GLP-1 or GLP-1/GIP therapies, though cross-trial comparisons should be read cautiously given differing designs and populations.[5]
In type 2 diabetes trials, retatrutide produced dose-dependent HbA1c reductions of roughly 1.7 to 2 percentage points, and an early MASLD substudy reported large reductions in liver fat.[6] These are meaningful research signals rather than approved-label outcomes, and long-term cardiovascular and safety endpoints are still being evaluated.
Calculator
Plan your own dose
Reconstituting a different vial size or targeting a different dose? Run the numbers.
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Reconstitution
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