Retatrutide Dosage Chart: Trial Titration Schedule
Retatrutide is an investigational, once-weekly triple agonist studied in separate dose groups and trial programs. This chart distinguishes the Phase 2 groups from the reported TRIUMPH-1 procedure, keeps concentration arithmetic separate from preparation instructions, and does not provide a personal regimen.
Retatrutide Trial Dosage Chart
The table reports the four-week escalation procedure described for the Phase 3 TRIUMPH-1 targets of 4, 9 and 12 mg; it is not a universal Phase 2/3 schedule. The separate Phase 2 obesity study tested 1, 4, 8 and 12 mg target groups with different starting doses. Read the dated Lilly TRIUMPH-1 report alongside the Jastreboff et al., NEJM 2023 publication and our mechanism overview rather than combining their procedures.
| Weeks | Reported weekly amount | Assigned target | Context |
|---|---|---|---|
| 1–4 | 2 mg | 4, 9 or 12 mg | Reported initial step before any assigned-target escalation |
| 5–8 | 4 mg | 4, 9 or 12 mg | The 4 mg target stops here; higher targets continue |
| 9–12 | 6 mg | 9 or 12 mg | Reported step for higher assigned targets |
| 13–16 | 9 mg | 9 or 12 mg | The 9 mg target stops here; the 12 mg target continues |
| 17+ | 12 mg | 12 mg only | Reported final step for the 12 mg target |
The Phase 2 targets were 1, 4, 8 and 12 mg. Its reported initial doses were 1 mg for the 1 mg target, 2 or 4 mg for the 4 and 8 mg targets, and 2 mg for the 12 mg target; the publication does not establish the TRIUMPH-1 intermediate steps for those groups. For a narrative walk-through rather than a table, see our retatrutide dosing guide and retatrutide dosing schedule.
How the Titration Schedule Works
TRIUMPH-1 reported four-week steps for its assigned 4, 9 and 12 mg targets. The Phase 2 publication reported gastrointestinal events as mostly mild or moderate and dose-related, with starting-dose differences; it does not establish that an individual will adapt on a fixed timetable. The product-specific context for tirzepatide and semaglutide should not be transferred to retatrutide.
A trial participant follows the assigned protocol and study team instructions; this page cannot determine whether an amount should be held or advanced. The starting dose page is background, not a selection rule. No claim here establishes that a faster or slower ramp improves outcomes.
Reconstitution and Concentration Reference
For an arithmetic example, total mass divided by final solution volume gives concentration; vial capacity and a diluent choice are separate questions. A product label states its own vehicle, compatibility and preparation requirements: the bacteriostatic-water label does not make its vehicle a universal retatrutide recipe.
| Vial mass | Final solution volume | Concentration | 2 mg arithmetic | 12 mg arithmetic |
|---|---|---|---|---|
| 10 mg | 1 mL | 10 mg/mL | 20 units | n/a (exceeds vial) |
| 10 mg | 2 mL | 5 mg/mL | 40 units | n/a (exceeds vial) |
| 20 mg | 2 mL | 10 mg/mL | 20 units | 120 U-100 units (1.2 mL) |
On a U-100 scale, one scale unit is 0.01 mL, so 100 U-100 units equals 1 mL; scale units are not a tick count or a drug unit. A 12 mg arithmetic example at 10 mg/mL needs 1.2 mL, which exceeds a 1 mL/100-unit syringe, but syringe capacities and graduation spacing vary. Consult the actual device and its manufacturer reference. Use the calculator below, and cross-check the method in our reconstitution guide and peptide reconstitution calculator.
Peptide Reconstitution Calculator
Calculate concentration and volume arithmetic from entered product values
Starting mass is an illustrative example. Replace it with the amount shown on the actual product label.
Enter the total volume after mixing, not the vial capacity. The starting mass and 2 mL volume are illustrative examples, not a prescribed regimen. The calculator does not select a diluent; use product-specific preparation instructions.
Optional arithmetic input; no amount is preselected. Results are calculated quantities, not dose recommendations.
Used only for theoretical arithmetic duration; it is not a treatment schedule or shelf-life calculation.
Enter peptide amount, final solution volume, and desired dose to see calculations
Disclaimer: This calculator is for research and educational purposes only. It is not medical advice. Always consult with a healthcare professional before using any peptide product. Verify all calculations independently.
Dose vs Weight-Loss Response
In the 48-week Phase 2 obesity trial, mean body-weight reductions differed by assigned target: 1 mg 8.7%, 4 mg 17.1%, 8 mg 22.8% and 12 mg 24.2%, versus 2.1% with placebo. The larger Phase 3 TRIUMPH-1 sponsor report describes the 12 mg target at 80 weeks as 28.3% under the efficacy estimand and 25.0% under the treatment-regimen estimand. These are different studies, populations, time points and estimands; neither is an individual forecast.
| Phase 2 assigned target | Mean body-weight reduction at 48 weeks |
|---|---|
| 1 mg | 8.7% |
| 4 mg | 17.1% |
| 8 mg | 22.8% |
| 12 mg | 24.2% |
These Phase 2 results are not a cross-trial ranking or a promise of response. More detail on outcomes sits in our retatrutide weight loss guide.
How Retatrutide Doses Compare to Other GLP-1 Drugs
Milligrams do not transfer between these drugs. Each molecule has different receptor targets and potency, so a dosage chart for one says nothing about the right dose of another.
| Drug | Receptor targets | Study or product context |
|---|---|---|
| Retatrutide | GIP + GLP-1 + glucagon | Highest target in trials summarized (12 mg weekly; investigational) |
| Tirzepatide | GIP + GLP-1 | Zepbound maximum 15 mg weekly (approved; product-specific) |
| Semaglutide | GLP-1 | Wegovy HD 7.2 mg weekly is approved for specified adult weight-management use; other indications and products differ |
The third receptor target distinguishes retatrutide from tirzepatide, but it does not create a milligram conversion. The FDA announcement for Wegovy HD is specific to adult weight-management use and does not make 2.4 mg a universal semaglutide maximum. See retatrutide vs tirzepatide and retatrutide vs semaglutide for the full comparison.
Side Effects by Dose Level
The Phase 2 publication reported gastrointestinal events as mostly mild or moderate and dose-related, and heart-rate increases that peaked around week 24 before falling. It does not support step-specific side-effect rates here. A receptor description alone does not establish a person's glucose response; the trial's monitoring and any symptoms require study-specific clinical guidance. Our retatrutide side effects guide provides additional context.
Why There Is No Official Prescribing Dose Yet
A dosage chart is normally anchored to an FDA-approved label that specifies the starting dose, titration intervals and maximum. Retatrutide has no such label. Lilly's current retatrutide status page describes it as investigational and not FDA approved. The honest scope of this chart is limited to reported study procedures and arithmetic examples, not an approved instruction or an approval forecast.
Related Guides
Frequently Asked Questions About Retatrutide
The Phase 2 obesity study used separate 1, 4, 8 and 12 mg target groups with different starting doses. The reported TRIUMPH-1 procedure used four-week steps of 2, 4, 6, 9 and 12 mg for assigned 4, 9 and 12 mg targets. These are study procedures, not a personal regimen; retatrutide remains investigational.
12 mg once weekly is the highest target described in the Phase 2 and TRIUMPH-1 obesity programs summarized here. Lilly reported the TRIUMPH-1 12 mg target as 28.3% at 80 weeks under the efficacy estimand and 25.0% under the treatment-regimen estimand. Those sponsor-reported results are not an approved regimen or an individual prediction.
The reported TRIUMPH-1 procedure used four-week steps for assigned 4, 9 and 12 mg targets. That interval does not establish a personal schedule, and the Phase 2 groups did not establish the same intermediate sequence. Follow the assigned study team's instructions rather than inferring an adjustment from this chart.
No FDA-approved retatrutide label or prescribing dose is established. Lilly's current status summary describes retatrutide as investigational. Trial procedures should not be converted into a general prescription or an approval/commercial timeline.
The table and calculator show arithmetic from entered mass, final solution volume and concentration. They do not choose a diluent or provide a home-mixing, sterility or storage recipe. Vehicle, compatibility and preparation instructions must come from the actual product or study team.
They are not interchangeable on a milligram basis. Tirzepatide has a product-specific 15 mg maximum, while retatrutide has a 12 mg target in the trials summarized here. Their receptor targets, formulations, indications and evidence differ, so a 12 mg retatrutide amount cannot be converted to a 15 mg tirzepatide amount.
The Phase 2 publication described gastrointestinal events as mostly mild or moderate and dose-related, and reported heart-rate increases that peaked around week 24 before falling. This page does not assign step-specific rates or infer an individual glucose response from one receptor target.
Charts can mix the Phase 2 1/4/8/12 mg target groups with the TRIUMPH-1 4/9/12 mg targets, or mistake a reported trial procedure for a universal schedule. This page keeps those programs and their outcomes separate and does not generate a personal regimen.
There is no FDA-approved retatrutide regimen. Trial participants use assigned procedures and monitoring; arithmetic on an outside product cannot verify identity, concentration, compatibility, sterility or suitability. This page documents reported research procedures, not a protocol to copy at home.