Retatrutide
How to reconstitute the 12 mg vial and convert any target dose into insulin units. Reconstitution math for the 6 mg and 12 mg vials. Retatrutide is investigational (not approved); published phase 2 trials studied once-weekly SC doses of 1–12 mg — shown for reference, not as a recommended dose.
No validated human dose. Retatrutide is a research-use peptide with no FDA-approved dose. The reconstitution math below is exact measurement — a calculator, not advice. Any usage figures are community-reported and clearly labeled, and none of this is medical advice.
Calculate for your vial
Enter the mg on your Retatrutide vial, the bacteriostatic water you added, and your target dose — it works out the exact units to draw on a U-100 insulin syringe, for whatever you personally have.
Reconstitution Calculator
Check the decimal. A misplaced decimal point here is a 10× dosing error. Re-read every number, and confirm your dose with a licensed clinician before you draw.
Educational only — not a dosing recommendation. This tool does the measurement math; it does not tell you what to take. On a U-100 insulin syringe, 100 units = 1 mL.
Dosing schedule
Retatrutide · fixed weekly step-up schedule
An investigational trial titration. Everyone escalated on a fixed schedule; heavier / more-tolerant participants reached the higher 8–12 mg targets that produced the greatest weight loss.
- 12–4 mg/wkWeeks 1–4Trial starting dose
- 2+2–4 mg every 4 wksEscalationToward assigned target
- 38 mg/wkTarget group
- 412 mg/wkHighest studied~24% mean loss at 48 wk
Retatrutide is investigational and not FDA-approved. In the trial, participants did not dose by body weight — they escalated on a fixed every-4-weeks schedule toward an assigned target (1, 4, 8 or 12 mg), with the highest targets producing the greatest weight loss. Any real-world use belongs entirely with a licensed clinician.
Source: Jastreboff et al., NEJM 2023 (NCT04881760) — investigational, NOT FDA-approved. Educational only — not medical advice and not a dosing recommendation. Any dosing decision belongs with a licensed clinician.
1 · Find your dose
Pick what you're using Retatrutide for and how much bacteriostatic water you added — this pulls out the exact units to draw and how often people report using it.
Phase-2 trial arms ran 1–12 mg/week; 12 mg was the HIGHEST STUDIED dose (Jastreboff, NEJM 2023 / NCT04881760) — not a target or recommendation. Most data centers on the lower 1–8 mg arms. Participants received 1 mg LY3437943 administered as SC injection QW.
- How / how often
- Route: subcutaneous
Observational human-trial dose — studied, NOT a target or recommendation. Phase 2 (NCT04881760). Source: https://clinicaltrials.gov/study/NCT04881760
At 3 mL this 12 mg vial is 4 mg/mL (40 mcg per unit). Use the full matrix below to convert a specific amount into U-100 units — measurement math, not a recommendation.
2 · Reconstitute it cleanly, step by step
How to turn the 12 mg powder into a measured liquid with clean, sterile technique. More water means each insulin unit holds less peptide — easier to measure small amounts accurately.
1Swab the stoppers
Wipe the rubber top of each vial with an alcohol pad and let it air-dry.
2Draw the water
Pull your bacteriostatic water up into the insulin syringe.
3Reconstitute
Inject it slowly down the inside wall of the peptide vial — never straight onto the powder.
4Swirl to dissolve
Gently swirl until the powder fully dissolves into a clear liquid. Never shake.
5Equalize, then draw
To draw a dose: push in an equal amount of air first to equalize the pressure, then pull your dose.
- 1
Swab both tops
Wipe the rubber top of the bacteriostatic-water vial and the Retatrutide vial stopper with a fresh alcohol pad, and let them air-dry. Never touch the needle or the stoppers after wiping.
Alcohol swab · let dry - 2
Draw the water
First pull 3 mL of air into the syringe and inject it into the bacteriostatic-water vial to equalize the pressure, then draw your 3 mL of water back out. Inject it into the Retatrutide vial down the inside glass wall, not onto the powder.
3 mL BAC water - 3
Swirl, don't shake
Gently swirl the 12 mg vial until the powder fully dissolves into a clear liquid. Never shake — shaking can damage the peptide and foam the solution.
Swirl, don't shake - 4
Know your strength
The vial is now 4 mg/mL. Each unit on a U-100 syringe holds about 40 mcg.
4 mg/mL - 5
Re-swab & draw your dose
Wipe the stopper again. With a fresh insulin syringe, pull back 100 units of air and inject it into the vial to equalize the pressure, then draw 100 units (1 mL) for a 4 mg dose.
100 units - 6
Store it right
Keep the mixed vial in the fridge, away from light. Use a new sterile syringe every time, never share, and drop used sharps in a proper container.
Refrigerate · fresh needle
What each water volume gives you:
3 · Full units reference
Every bacteriostatic-water volume (rows) against every target dose (columns) — each cell is the U-100 units and the exact draw in mL. The highlighted row is the easiest volume to measure.
| BAC water | Concentration | Per unit | 1 mg | 4 mg | 8 mg |
|---|---|---|---|---|---|
| 1 mL | 12 mg/mL | 120 mcg | 8.3u0.083 mL | 33.3u0.333 mL | 66.7u0.667 mL |
| 2 mL | 6 mg/mL | 60 mcg | 16.7u0.167 mL | 66.7u0.667 mL | 133.3u1.333 mL |
| 3 mLeasy pick | 4 mg/mL | 40 mcg | 25u0.25 mL | 100u1 mL | 200u2 mL |
4 · Everyday usage
Retatrutide is investigational — not FDA-approved — but unlike most research peptides it has real published human trial doses. The figures below are the doses STUDIED in trials, not a recommendation, and the research-chemical vial is not the trial product.
Studied: Obesity
Studied in trialsPhase-2 trial arms ran 1–12 mg/week; 12 mg was the HIGHEST STUDIED dose (Jastreboff, NEJM 2023 / NCT04881760) — not a target or recommendation. Most data centers on the lower 1–8 mg arms. Participants received 1 mg LY3437943 administered as SC injection QW.
- Frequency
- Route: subcutaneous
Observational human-trial dose — studied, NOT a target or recommendation. Phase 2 (NCT04881760). Source: https://clinicaltrials.gov/study/NCT04881760
Studied: Type 2 Diabetes
Studied in trialsParticipants received 0.5 mg LY3437943 administered as SC (subcutaneous) injection once weekly (QW).
- Frequency
- Route: subcutaneous
Observational human-trial dose — studied, NOT a target or recommendation. Phase 2 (NCT04867785). Source: https://clinicaltrials.gov/study/NCT04867785
Frequently asked questions
How many insulin units is 1 mg of Retatrutide from a 12 mg vial?
- Reconstituting a 12 mg vial with 3 mL of bacteriostatic water gives 4 mg/mL — about 40 mcg per unit. Drawing 1 mg is 0.25 mL, or 25 units on a U-100 insulin syringe. This is measurement math, not a dose recommendation.
How many insulin units is 4 mg of Retatrutide from a 12 mg vial?
- Reconstituting a 12 mg vial with 3 mL of bacteriostatic water gives 4 mg/mL — about 40 mcg per unit. Drawing 4 mg is 1 mL, or 100 units on a U-100 insulin syringe. This is measurement math, not a dose recommendation.
Are there real human doses for retatrutide?
- Yes, but only inside clinical trials. Eli Lilly's phase 2 obesity study (NEJM 2023, NCT04881760) used once-weekly subcutaneous doses titrated up to 1, 4, 8 or 12 mg. Retatrutide is investigational and not FDA-approved, so there is no validated or recommended consumer dose — these figures describe what was studied, and decisions belong with a licensed clinician.
References
WikiPeps is a community reference. Reconstitution figures are deterministic measurement math; usage figures are sourced and labeled. Nothing here is medical advice, a recommendation, or an offer to sell peptides — dosing decisions belong with a licensed clinician.