Retatrutide Reconstitution Math — 5mg and 10mg Vial Calculations for the Jastreboff Phase 2 Dose Schedule
This is the complete reconstitution math, every titration step, both vial sizes, with the unit math worked out.
1. The Jastreboff 2023 dose schedule — the reference
Jastreboff et al. 2023 in the New England Journal of Medicine reported the phase 2 trial of retatrutide for obesity. The titration schedule, which has become the de-facto research reference:
| Week | Weekly dose | Schedule |
|---|---|---|
| 1-4 | 2 mg | Starting titration |
| 5-8 | 4 mg | Second titration |
| 9-12 | 8 mg | Third titration |
| 13+ | 12 mg | Maintenance (top arm) |
The trial also ran 4 mg and 8 mg maintenance arms. Mean weight reduction at 48 weeks: 8.7% (1 mg arm), 17.1% (4 mg), 22.8% (8 mg), 24.2% (12 mg). The dose-response is roughly linear up to 8 mg and flattens between 8 and 12 mg — most research protocols target the 8 mg maintenance dose as the cost-efficient sweet spot.
2. Choosing your vial — 5 mg or 10 mg
REVIVE LAB UAE stocks both. The decision logic:
| Vial size | Best for | Weeks per vial (8 mg maintenance) | Cost per mg |
|---|---|---|---|
| 5 mg | Titration phase (weeks 1-8 at 2-4 mg) | ~2.5 weeks at 2 mg; ~1.25 weeks at 4 mg | Higher per mg |
Practical full-protocol math: a 12-week titration (4 weeks × 2 mg + 4 weeks × 4 mg + 4 weeks × 8 mg) = 56 mg total. That's eleven 5 mg vials or six 10 mg vials. Most researchers ordering a full titration sleeve buy 5 mg for the titration phase and switch to 10 mg vials for maintenance.
3. Reconstitution scenarios — 5 mg vial
Three common bacteriostatic water ratios on the 5 mg vial:
4. Reconstitution scenarios — 10 mg vial
For 8 mg maintenance, 10 mg + 1 mL = 10 mg/mL gives 80 U — a clean single-syringe draw.
6. Bac water vs sterile water
Bacteriostatic water (0.9% benzyl alcohol preservative) is the standard reconstitution solvent for multi-dose protocols. Sterile water is only suitable for single-use vials drawn immediately. Retatrutide reconstituted in bac water and refrigerated at 2-8 °C is stable for 28-30 days — enough for one full vial of weekly dosing. Full bac water vs sterile comparison sits in our peptide reconstitution guide.
7. Storage during the dose week
Reconstituted retatrutide should live in the refrigerator at 2-8 °C between weekly injections. UAE summer ambient (45 °C+ peaks in July-August) destroys peptide stability rapidly — never leave a reconstituted vial out at room temperature for more than 2-3 hours total cumulative time. If using insulated pouch for transport, include cold-pack and keep the vial pressed against the cold-pack throughout transit.
9. UAE supply context
Retatrutide is REVIVE LAB UAE's highest-volume SKU. Both 5 mg and 10 mg vials are stocked. Lot-level HPLC certificate of analysis confirms peptide identity and purity ≥98% on every batch. The full Jastreboff-anchored research overview sits in our retatrutide dosing protocol writeup.
Retatrutide UAE ships same-day Dubai on orders before 4 PM, 24 hours nationwide, cold-pack insulation year-round.
References
- Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. PubMed
- Rosenstock J, Frias J, Jastreboff AM, et al. Retatrutide in phase 2 type 2 diabetes — Glycaemic and weight outcomes. Lancet. 2023;402(10401):529-544. PubMed
- Coskun T, Urva S, Roell WC, et al. LY3437943, a novel triple GIP/GLP-1/glucagon receptor agonist. Cell Metab. 2022;34(9):1234-1247. PubMed
- Sanyal AJ, Kaplan LM, Frias JP, et al. Triple hormone receptor agonist retatrutide for MASLD — Subgroup analysis. Nat Med. 2024;30:2037-2048. PubMed
- Reagan-Shaw S, Nihal M, Ahmad N. Dose translation from animal to human studies revisited. FASEB J. 2008;22(3):659-661. PubMed