Retatrutide 30mg Dosage Chart: IU Per Dose at 10mg/mL

Quick Reference: Retatrutide 30mg Dosage Chart

The complete titration lookup for a 30mg vial reconstituted with 3mL of bacteriostatic water (10mg/mL concentration). Read the dose on the left and the IU draw on the right.

* The 12mg draw exceeds the 100 IU capacity of a standard U-100 insulin syringe. Use a 1.5mL or 2mL syringe for a single draw, or split into two 60 IU draws administered back-to-back at the same injection site.

Why 3mL BAC Water for a 30mg Vial?

The math is straightforward: 30mg of retatrutide powder divided by 3mL of bacteriostatic water gives a 10mg per mL solution. That concentration is the corpus standard for the 30mg vial because every titration step lands on a round IU value that is easy to read on an insulin syringe.

Compare the alternatives. At 2mL of BAC water the concentration would be 15mg/mL and 8mg = approximately 53 IU, a non-round number that is harder to read accurately. At 5mL of BAC water it is 6mg/mL and the 2mg starting dose = approximately 33 IU, again awkward. The 3mL volume keeps the math clean and the draws inside or near the standard 1mL syringe capacity for the first three steps.

For the underlying BAC water arithmetic across every vial size and concentration combination, the how much BAC water for retatrutide page covers each vial size in detail.

The Retatrutide 30mg Dosage Chart Titration: Why This Sequence

The 2mg, 4mg, 8mg, 12mg ladder comes directly from the Phase 2 trial of retatrutide published by Jastreboff and colleagues in the New England Journal of Medicine in 2023. Each step held for 4 weeks before escalation. The trial used randomized maintenance arms at 1mg, 4mg, 8mg, and 12mg; the higher-dose arms titrated from 2mg every 4 weeks to reach their target. The 12mg arm produced the headline 24.2% body weight loss at 48 weeks.

Why this exact spacing? The doubling pattern reflects the pharmacology. Retatrutide is a triple-receptor agonist (GLP-1, GIP, and glucagon) with a half-life of approximately 6 days, which places steady-state at roughly 4 to 5 weeks per dose level. The 4-week hold matches steady-state timing so each dose escalation lands on a fully equilibrated baseline rather than a rising plasma concentration.

The trial also found GI adverse events were the most common and dose-related, mostly mild to moderate. In its posted results, the 12mg group saw nausea in 45% (versus 11% on placebo), vomiting in 19%, constipation in 16%, and diarrhea in 15%. The slow titration is designed to give the gut time to adapt at each step.

Holding a Dose Longer Than 4 Weeks

The 4-week interval is a minimum, not a maximum. Many users report holding 4mg for an additional 4 to 8 weeks before stepping to 8mg if GI side effects are significant. This is not a separate protocol; it is a titration pause inside the same Phase 2 framework. The IU draws stay identical (40 IU at 4mg, 80 IU at 8mg) regardless of how long each step is held.

Some users also stop short of 12mg if 8mg already produces the desired effect. The Phase 2 trial included a 4mg maintenance arm that produced meaningful weight loss without requiring escalation to 8mg or 12mg, so partial titration is supported by the trial design.

How Long Does a 30mg Retatrutide Vial Last?

A 30mg vial reconstituted to 10mg/mL contains 3mL of solution. Theoretical dose count by titration step:

• 2mg weekly (20 IU): 15 doses theoretical, roughly 15 weeks.
• 4mg weekly (40 IU): 7 to 8 doses, roughly 7 to 8 weeks.
• 8mg weekly (80 IU): 3 to 4 doses, roughly 4 weeks.
• 12mg weekly (120 IU): 2 to 3 doses, roughly 2.5 weeks.

In practice the storage stability window is usually the limiting factor, not the volume. Reconstituted peptides are typically stable for 28 to 60 days under refrigeration depending on the compound and the BAC water preservative. For users on the higher 8mg or 12mg doses, a single 30mg vial covers roughly one titration step before the stability window closes. For the lower 2mg starting step the vial volume far exceeds the stability window, so reconstituting with less BAC water can make sense if the user wants to finish the vial within the freshness window.

Syringe Selection by Dose

The first three titration steps all fit a standard 1mL U-100 insulin syringe with capacity to spare. The 12mg maximum dose is the only step that exceeds the standard syringe. Two options for 12mg:

• 1.5mL or 2mL syringe (cleaner). A single 120 IU draw, single injection. Most users with 12mg as a maintenance dose stock 1.5mL syringes.
• Split into two 60 IU draws (workaround). Two consecutive injections at the same site or two nearby sites. Adds complexity and a second needle stick but uses the standard syringe stock.

30mg Vial vs Other Sizes: When the 30mg Wins

The 30mg vial is the large-format workhorse for users past the early titration weeks. Smaller vials (10mg, 15mg, 20mg) reconstituted at 5mg/mL or 7.5mg/mL produce larger, easier-to-read draws at the lowest doses but force a split injection at 8mg and above. The 30mg + 3mL setup is the opposite trade: smaller draws across the board but every step from 2mg through 8mg stays inside a standard syringe.

• 10mg vial + 2mL = 5mg/mL. 2mg = 40 IU (very clean), 4mg = 80 IU (clean), 8mg = 160 IU (split draw required). Best for users still on 2mg or 4mg titration.
• 30mg vial + 3mL = 10mg/mL. 2mg = 20 IU, 4mg = 40 IU, 8mg = 80 IU (all standard syringe), 12mg = 120 IU (1.5mL syringe). Best for users at 4mg and above.

For the complete multi-vial reference covering every common BAC water volume across all six standard vial sizes, see the full reconstitution chart. For a deeper comparison of the 5mg/mL versus 10mg/mL concentration choice, see retatrutide dosing in units.

Reconstitution Step Recap for a 30mg Vial

This article assumes the vial is already reconstituted at the standard 10mg/mL concentration. If the vial is still in dry powder form, the high-level recipe is: draw 3mL of bacteriostatic water (0.9% benzyl alcohol preservative) into a syringe, slowly inject it down the inside wall of the 30mg vial (do not aim at the powder directly), gently swirl until clear, and refrigerate. Do not shake.

For the full step-by-step mixing procedure with vial-cap prep, swirl-versus-shake guidance, and timing, the step-by-step reconstitution guide covers it. Once the vial is reconstituted, this dosage chart takes over.

Investigational Drug Notice

References

1. Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial. New England Journal of Medicine. 2023;389(6):514-526. DOI: 10.1056/NEJMoa2301972. (Anchor trial: confirms the 2mg, 4mg, 8mg, 12mg titration ladder with 4-week intervals; 24.2% body weight loss on 12mg at 48 weeks; dose-related GI adverse events, with per-symptom rates from the trial's posted results on ClinicalTrials.gov, NCT04881760.)
2. Coskun T, Urva S, Roell WC, et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept. Cell Metabolism. 2022;34(9):1234-1247.e9. DOI: 10.1016/j.cmet.2022.07.013. PMID: 35985340. (Confirms approximately 6-day half-life, 95% subcutaneous bioavailability, and the once-weekly dosing rationale.)
3. ClinicalTrials.gov. TRIUMPH-1: A Study of Retatrutide (LY3437943) in Participants With Obesity. NCT05929066. clinicaltrials.gov/study/NCT05929066. (Current Phase 3 registry record confirming investigational status and ongoing trials of the Phase 2 titration protocol at scale.)
4. BD Diabetes Care. Insulin Syringes - Product Information for U-100 Syringes. bd.com/en-us/products/diabetes/diabetes-products/insulin-syringes. (Manufacturer reference for U-100 calibration: 100 IU equals 1mL, the basis for every IU value on this page.)
5. United States Pharmacopeia. General Chapter <797> Pharmaceutical Compounding: Sterile Preparations. 2023. usp.org/compounding/general-chapter-797. (Compounding standards governing beyond-use dating and stability for reconstituted aqueous peptide preparations.)
6. ClinicalTrials.gov. A Study of LY3437943 in Participants Who Have Obesity or Overweight (NCT04881760). Posted results, adverse events. clinicaltrials.gov/study/NCT04881760. (Source of the Phase 2 per-symptom rates in the 12mg group: nausea 45% versus 11% on placebo, vomiting 19%, constipation 16%, and diarrhea 15%.)

More Retatrutide Guides on GLP3Planner