Clean the vial stopper and gather the sterile supplies required by the research procedure.
Retatrutide Quick Reference (10 mg Vial)
Vial size
10 mg Retatrutide
Concentration
10 mg/mL
Final volume
1 mL
Storage
100 mcg in 0.01 mL
Research context:Ā For mechanisms, human and preclinical research, limitations, and safety context, read theĀ Retatrutide Peptide research overview.
Retatrutide Dosage Chart (10 mg Vial)
The same phase 2 and phase 3 schedules converted for a 10 mg vial
Phase 2 Trial Schedule (1 mL = 10 mg/mL)
| Study Phase | Weekly Dose | U-100 Units | Volume |
|---|---|---|---|
| Weeks 1 to 4 | 2 mg | 20 units | 0.2 mL |
| Weeks 5 to 8 | 4 mg | 40 units | 0.4 mL |
| Weeks 9 to 12 | 8 mg | 80 units | 0.8 mL |
| Weeks 13+ | 12 mg | 120 units | 1.2 mL |
Frequency:Ā Once weekly by subcutaneous administration. This table shows the lower-start 12 mg arm from the 48-week phase 2 obesity trial. The study also evaluated separate 1 mg, 4 mg, and 8 mg target arms.[1]Ā Rows above 100 units exceed the capacity of one 1 mL syringe, so the supply calculation counts the required number of syringes.
Phase 3 Trial Schedule (1 mL = 10 mg/mL)
| Study Phase | Weekly Dose | U-100 Units | Volume |
|---|---|---|---|
| Weeks 1 to 4 | 2 mg | 20 units | 0.2 mL |
| Weeks 5 to 8 | 4 mg | 40 units | 0.4 mL |
| Weeks 9 to 12 | 6 mg | 60 units | 0.6 mL |
| Weeks 13 to 16 | 9 mg | 90 units | 0.9 mL |
| Weeks 17+ | 12 mg | 120 units | 1.2 mL |
Frequency:Ā Once weekly by subcutaneous administration. The phase 3 program began at 2 mg and increased every four weeks until the assigned 4 mg, 9 mg, or 12 mg target was reached.[2][3]Ā Rows above 100 units exceed the capacity of one 1 mL syringe, so the supply calculation counts the required number of syringes.
Reconstitution Steps
AddĀ 1 mL bacteriostatic waterĀ slowly down the vial wall.
Gently swirl or roll until dissolved. Do not shake.
Label the vialĀ 10 mg/mLĀ with the preparation date and follow the documented refrigerated storage period.
The weekly amounts remain identical across the Retatrutide family. The 10 mg vial changes only the concentration, U-100 units, volume, and supply calculations.
Supplies Needed
Straightforward 12-week and 24-week planning for a 10 mg vial at 10 mg/mL.
- Retatrutide vials (10 mg each):
- Phase 2, 12 weeks:Ā MinimumĀ 6 vialsĀ (56 mg required).
- Phase 2, 24 weeks:Ā MinimumĀ 20 vialsĀ (200 mg required).
- Phase 3, 12 weeks:Ā MinimumĀ 5 vialsĀ (48 mg required).
- Phase 3, 24 weeks:Ā MinimumĀ 18 vialsĀ (180 mg required).
- U-100 insulin syringes (1 mL capacity):
- Phase 2, 12 weeks:Ā 12 new syringes.
- Phase 2, 24 weeks:Ā 36 new syringes.
- Phase 3, 12 weeks:Ā 12 new syringes.
- Phase 3, 24 weeks:Ā 32 new syringes.
- Bacteriostatic water (10 mL bottles):
- Phase 2, 12 weeks:Ā 1 bottle by volume (6 mL required).
- Phase 2, 24 weeks:Ā 2 bottles by volume (20 mL required).
- Phase 3, 12 weeks:Ā 1 bottle by volume (5 mL required).
- Phase 3, 24 weeks:Ā 2 bottles by volume (18 mL required).
- Alcohol swabs:
- Phase 2, 12 weeks:Ā 24 swabs minimum; 1 box of 100 covers the calculation.
- Phase 2, 24 weeks:Ā 72 swabs minimum; 1 box of 100 covers the calculation.
- Phase 3, 12 weeks:Ā 24 swabs minimum; 1 box of 100 covers the calculation.
- Phase 3, 24 weeks:Ā 64 swabs minimum; 1 box of 100 covers the calculation.
Retatrutide Vial and Research Context
- Reconstitute:Ā AddĀ 1 mLĀ of bacteriostatic water to produceĀ 10 mg/mL.
- Research frequency:Ā Once weeklyĀ by subcutaneous administration in the cited human trials.[1][3][5]
- Weekly research range:Ā The cited programs evaluated target amounts throughĀ 12 mg weekly.[1][2][3]
- Easy measuring:Ā 1 U-100 unit = 0.01 mL = 100 mcg.
- Vial size:Ā The 10 mg label is total nominal vial content, not a weekly amount. Weekly research amounts above 10 mg require enough vials to supply the total nominal mass.
- Vial coverage:Ā At theĀ 2 mg research stage, one vial suppliesĀ 5 full weekly amounts. At theĀ 12 mg research stage, the 12 mg amount requiresĀ 2 separate 10 mg vialsĀ by nominal mass. These are mass calculations, not vial storage or discard periods.
Protocol Overview
Quick reference for the shared Retatrutide research schedules.
- Route:Ā Subcutaneous administration in the cited trials.[1][3][5]
- Frequency:Ā Once weekly.
- Research targets:Ā Phase 2 studied 1 mg, 4 mg, 8 mg, and 12 mg groups; phase 3 studied 4 mg, 9 mg, and 12 mg targets.[1][2][3]
- Concentration:Ā 10 mg divided by 1 mL equals 10 mg/mL.
- Unit conversion:Ā 1 U-100 unit equals 100 mcg.
Dosing Protocol
The tables keep the phase 2 and phase 3 schedules separate.
- Phase 2 lower-start 12 mg arm:Ā 2 mg, 4 mg, 8 mg, then 12 mg in four-week steps.[1]
- Phase 3 12 mg target:Ā 2 mg, 4 mg, 6 mg, 9 mg, then 12 mg in four-week steps.[2][3]
- Frequency:Ā Once weekly by the subcutaneous route.
- Measurement:Ā Use the units and mL displayed beside each weekly amount.
- Consistency:Ā Vial size does not change the weekly research schedule.
Storage Instructions
Use the storage directions for the exact supplied formulation.
- Before preparation:Ā Keep the vial dry, protected from light, and stored according to its documentation.[16]
- After preparation:Ā Refrigerate only as permitted by the exact formulation and diluent instructions.
- Labeling:Ā Record the concentration, preparation date, storage conditions, and documented discard date.
- Handling:Ā Avoid unnecessary agitation and repeated freeze-thaw cycles.[16][17]
Important Notes
Practical details for reading the schedules and calculations correctly.
- The weekly amounts remain the same across every Retatrutide vial size. Only the vial concentration, U-100 units, volume, and supply totals change.
- The phase 2 and phase 3 tables represent separate research schedules and should not be combined into one progression.[1][2][3]
- Use a new sterile syringe for each injection and place used sharps in an appropriate container.[14][15]
- Rotate subcutaneous sites according to the governing research procedure.[13][14][15]
- Record the weekly amount, calculated units, volume, date, and administration site consistently.
How This Works
Clinical Benefits
Results below summarize observations from controlled human research.
- The phase 2 obesity trial reported dose-related body-weight reductions across the studied target groups through 48 weeks.[1]
- The phase 2 diabetes trial reported reductions in glycated hemoglobin and body weight across studied retatrutide groups.[5]
- TRANSCEND-T2D-1 reported improvements in glycated hemoglobin and body weight at 40 weeks in adults with type 2 diabetes.[3]
- Cardiometabolic measurements were evaluated as secondary outcomes in the clinical research programs.[1][3][5][10]
Side Effects
Safety findings remain specific to the studied populations, products, schedules, and monitoring plans.
- Gastrointestinal events, including nausea, diarrhea, vomiting, and constipation, were among the most commonly reported events.[1][3][5][12]
- Events were more frequent during dose escalation and were generally mild to moderate in the phase 2 obesity study.[1]
- A lower 2 mg starting amount improved gastrointestinal tolerability compared with a 4 mg start in the phase 2 obesity trial.[1]
- Dose-dependent heart-rate increases were observed in phase 2 research and declined after peaking during follow-up.[1]
Lifestyle Factors
Consistent study conditions make weekly observations easier to interpret.
- Record diet, physical activity, sleep, hydration, and gastrointestinal symptoms consistently.
- Use the same body-weight, waist, glucose, and laboratory measurement methods throughout the observation period.
- Compare results within the same population, dose arm, follow-up period, and analysis plan.
Injection Technique
General subcutaneous research technique should follow the approved institutional or laboratory procedure.[13][14][15]
- Use a new sterile syringe and needle for every injection and each separate vial entry.
- Clean the vial stopper and selected site, then allow the surface to dry.
- Use the needle length, angle, and skinfold method specified by the governing procedure.
- Rotate sites systematically and document each administration.
- Place used sharps immediately in an appropriate sharps container.
Important Research Note
Suggested weekly titration approach based on clinical trial designs[1][6].
- Start:Ā 0.6Ā mg weekly for the first 2 weeks to assess tolerability.
- Escalate:Ā Double the dose every 2 weeks (0.6 ā 1.2 ā 2.4 ā 4.5Ā mg) as tolerated.
- Target:Ā 4.5Ā mg weekly by Weeks 7ā8; maintain at this dose.
- Frequency:Ā Once per week (subcutaneous) on the same day each week.
- Timing:Ā Any consistent time; rotate injection sites.
References
-
New England Journal of Medicine (2023): Triple-Hormone-Receptor Agonist Retatrutide for Obesity: randomized phase 2 trial
View Source -
Eli Lilly and Company (2026): Phase 3 target doses and four-week escalation schedule
View Source -
Cell Metabolism (2022): Discovery and translational pharmacology of LY3437943
View Source -
The Lancet (2023): Retatrutide for type 2 diabetes: randomized phase 2 trial
View Source -
ClinicalTrials.gov: Phase 2 retatrutide obesity study NCT04881760
View Source
