Retatrutide Dosing Calculator & Schedule
Retatrutide is dosed as a once-weekly subcutaneous injection with gradual dose escalation over 12-16 weeks. The clinical trial protocol uses 4-week titration steps starting at 2 mg and escalating to a maintenance dose of 4 mg, 9 mg, or 12 mg depending on the trial.
Since retatrutide is not yet FDA-approved, there are no official prescribing guidelines. The schedules below are based on the Phase 2 trial (NEJM 2023) and the TRIUMPH Phase 3 program protocols.
Retatrutide Dose Calculator
Use the interactive retatrutide calculator below to plan your dose escalation timeline with personalized dates, or calculate reconstitution volumes for your vial setup.
Dose Escalation Timeline
Enter your start date and target dose to see your personalized titration schedule with calendar dates.
| Weeks | Dose |
|---|---|
| 1–4 | 2 mg |
| 5–8 | 4 mg |
| 9–12 | 6 mg |
| 13–16 | 9 mg |
| 17+ | 12 mg |
Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Dosing schedules are based on the Phase 3 TRIUMPH clinical trial protocols. Always follow your healthcare provider's instructions.
TRIUMPH Phase 3 Titration Schedule
The standard TRIUMPH Phase 3 dose escalation:
9 mg Target
| Weeks | Dose | Notes |
|---|---|---|
| 1–4 | 2 mg | Starting dose — body adjusts, minimal GI effects |
| 5–8 | 4 mg | First therapeutic dose, appetite suppression begins |
| 9–12 | 6 mg | Continued escalation, side effects stabilize |
| 13+ | 9 mg | Maintenance dose |
12 mg Target
| Weeks | Dose | Notes |
|---|---|---|
| 1–4 | 2 mg | Starting dose |
| 5–8 | 4 mg | Appetite suppression begins |
| 9–12 | 6 mg | Side effects stabilize |
| 13–16 | 9 mg | Approaching maintenance |
| 17+ | 12 mg | Maximum maintenance dose |
Each escalation step lasts 4 weeks — enough time to reach steady state (given retatrutide's ~6-day half-life) and assess tolerability before increasing.
Weight Loss by Dose
Phase 3 (TRIUMPH-4, 68 Weeks)
| Dose | Weight Loss (%) | Weight Loss (lbs) | ≥25% Lost | ≥30% Lost |
|---|---|---|---|---|
| 12 mg | -28.7% | ~71 lbs | 58.6% | 39.4% |
| 9 mg | -26.4% | ~64 lbs | 47.7% | 30.5% |
| Placebo | -2.1% | ~5 lbs | 1.3% | 0.8% |
Average baseline weight in TRIUMPH-4 was 248.5 lbs (BMI ~40.4).
Phase 2 (48 Weeks)
| Dose | Weight Loss (%) | Weight Loss (kg) | ≥10% Lost | ≥15% Lost |
|---|---|---|---|---|
| 12 mg | -24.2% | -24.0 kg | 100% | 93% |
| 8 mg | -22.8% | -24.2 kg | 100% | 91% |
| 4 mg | -17.3% | -17.5 kg | 100% | 75% |
| 1 mg | -8.7% | -8.7 kg | 85% | 28% |
| Placebo | -2.1% | -2.0 kg | 27% | 2% |
The difference between 8 mg and 12 mg was relatively small in Phase 2 (~1.4 percentage points), but TRIUMPH-4 Phase 3 showed a more meaningful 2.3-point gap between 9 mg and 12 mg over a longer treatment period.
Projected Weight Loss by Starting Weight
Based on Phase 3 data (12 mg dose, 68 weeks):
| Starting Weight | Projected Loss (~29%) | Projected Final Weight |
|---|---|---|
| 200 lbs (91 kg) | ~58 lbs | ~142 lbs |
| 225 lbs (102 kg) | ~65 lbs | ~160 lbs |
| 250 lbs (113 kg) | ~72 lbs | ~178 lbs |
| 275 lbs (125 kg) | ~80 lbs | ~195 lbs |
| 300 lbs (136 kg) | ~87 lbs | ~213 lbs |
| 350 lbs (159 kg) | ~101 lbs | ~249 lbs |
These are averages based on 28.7% mean weight loss. Individual results vary — some lose more, some less.
When to Hold a Dose Increase
Escalation should only proceed if the current dose is well-tolerated. Consider staying at your current dose for an additional 2-4 weeks if you experience:
- Persistent nausea or vomiting lasting more than 3 days
- Rapid weight loss exceeding 3-4 lbs per week
- Severe constipation or diarrhea
- Signs of dehydration
- Significant injection site reactions
The goal is to reach the maintenance dose gradually. Rushing escalation increases the risk and severity of side effects without improving long-term outcomes.
What If You Miss a Dose
- Within 3 days of your scheduled injection: take it as soon as you remember
- More than 3 days past your scheduled day: skip the missed dose and resume on your next regular injection day
- Never double up doses
- Because of the ~6-day half-life, missing one dose does not eliminate the drug from your system — you will still have therapeutic levels
How Dosing Compares
| Retatrutide | Tirzepatide (Mounjaro/Zepbound) | Semaglutide (Wegovy) | |
|---|---|---|---|
| Starting dose | 2 mg/week | 2.5 mg/week | 0.25 mg/week |
| Max dose | 12 mg/week | 15 mg/week | 2.4 mg/week |
| Titration interval | 4 weeks | 4 weeks | 4 weeks |
| Steps to max | 5 steps (2→4→6→9→12) | 4 steps (2.5→5→7.5→10→12.5→15) | 5 steps (0.25→0.5→1→1.7→2.4) |
| Half-life | ~6 days | ~5 days | ~7 days |
| Max weight loss | -28.7% | -22.5% | -14.9% |
All three drugs follow the same "start low, go slow" principle with 4-week escalation intervals. For detailed pharmacokinetics, see Retatrutide Half-Life.
Frequently Asked Questions
What dose of retatrutide produces the most weight loss?
The 12 mg dose produced the most weight loss in both Phase 2 (-24.2% at 48 weeks) and Phase 3 (-28.7% at 68 weeks). However, the 9 mg dose achieved close results (-26.4%) with lower dysesthesia rates (8.8% vs 20.9%).
Can I start at a higher dose?
No. Clinical trials always begin at 2 mg and escalate gradually over 12-16 weeks. Starting at a higher dose dramatically increases the risk and severity of gastrointestinal side effects. The gradual approach allows your body to adjust.
How long until I see results?
Appetite suppression typically begins within the first week. Measurable weight loss usually appears by weeks 2-4. The steepest rate of loss occurs after reaching the full maintenance dose (usually around weeks 12-24). See Retatrutide Results: Before and After for the full timeline.
Is 9 mg or 12 mg better?
The 12 mg dose produces slightly more weight loss (~2 percentage points more than 9 mg) but has significantly higher dysesthesia rates (20.9% vs 8.8%). The choice between the two — when retatrutide is approved — will depend on individual response, tolerability, and your doctor's recommendation.
What is the dosing for type 2 diabetes?
The TRIUMPH-2 trial (T2D + obesity) tests 4 mg, 9 mg, and 12 mg maintenance doses. Phase 2 T2D data showed HbA1c reductions of up to -2.02% at the 12 mg dose. See Retatrutide for Type 2 Diabetes and Dosage & Dosing Guide for details.
Sources
- Jastreboff, A.M., et al. (2023). Triple-Hormone-Receptor Agonist Retatrutide for Obesity. NEJM. DOI: 10.1056/NEJMoa2301972.
- Eli Lilly. (2025). TRIUMPH-4 results. Press release.
- Urva, S., et al. (2022). Phase 1b retatrutide trial. The Lancet. DOI: 10.1016/S0140-6736(22)02033-5.
- Giblin, M.J., et al. (2026). Design of the TRIUMPH Phase 3 program. Diabetes, Obesity and Metabolism. PubMed.
Medical Disclaimer
The content on glp3.wiki is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Retatrutide is an investigational drug that has not been approved by the FDA. The dosing information above is based on clinical trial protocols — final prescribing guidelines will be published upon regulatory approval.
Do not self-administer any investigational drug or modify your medication dosing without consulting a qualified healthcare provider.
This site is not affiliated with Eli Lilly and Company or any pharmaceutical manufacturer.
Sources
- Phase 2 trial (NEJM)
NEJM
- TRIUMPH-4 results
Eli Lilly
Related reading
Retatrutide Dosage & Dosing Guide
How retatrutide is dosed in clinical trials — titration schedule, dose levels, and what each dose achieved.
Retatrutide Half-Life and Pharmacokinetics
Retatrutide has a ~6-day half-life achieved through fatty acid albumin binding — comparable to semaglutide (~7 days) and tirzepatide (~5 days).
How to Inject Retatrutide
Once-weekly subcutaneous injection using a pre-filled pen. Same technique as Mounjaro — here's the step-by-step guide.