Free retatrutide reconstitution calculator. Enter vial size (5-15 mg), BAC water volume, and weekly dose to get concentration, syringe units, and doses per vial. Includes the Phase 2/3 trial titration protocol (1-12 mg weekly), triple-agonist dosing reference, and comparison with tirzepatide. Verify retatrutide quality with independent lab test data on Peptigrity.
Educational tool for research use. Not medical advice — it calculates what you enter, it doesn't recommend a dose.
Draw the syringe up to
That's one 2 mg dose. Add 2 mL of water to your 10 mg vial first.
| Step | Dose | Draw on a U-100 | Doses per vial |
|---|---|---|---|
| Tier 1 (start) | 2 mg | 40 units | 5 |
| Tier 2 | 4 mg | 80 units | 2 |
| Tier 3 | 8 mg | 160 units | 1 |
| Phase 3 target | 9 mg | 180 units | 1 |
| Tier 4 (max) | 12 mg | 240 units | — |
Tap any row to load that dose into the calculator above.
The Phase 2 trial (Jastreboff et al., NEJM 2023, n=338) established a 4-week step-up escalation from 2 mg to 12 mg. Participants who started at higher doses or escalated too quickly experienced nearly double the rate of gastrointestinal side effects. Phase 3 TRIUMPH trials evaluate 4 mg, 9 mg, and 12 mg as maintenance targets.
| Titration Tier | Weekly Dose | Weeks | At 6 mg/mL | At 10 mg/mL | At 20 mg/mL |
|---|---|---|---|---|---|
| Tier 1 (starting) | 2 mg | Weeks 1-4 | ~33 units | 20 units | 10 units |
| Tier 2 | 4 mg | Weeks 5-8 | ~67 units | 40 units | 20 units |
| Tier 3 | 8 mg | Weeks 9-12 | Exceeds 100u | 80 units | 40 units |
| Tier 4 (Phase 2 max) | 12 mg | Week 13+ | Exceeds 100u | Exceeds 100u | 60 units |
| Phase 3 targets | 9 mg | Maintenance | Exceeds 100u | 90 units | 45 units |
At 20 mg/mL (20 mg vial + 1 mL, or 30 mg vial + 1.5 mL), the entire titration schedule through 12 mg fits within 60 units - the cleanest measurement. The calculator flags syringe capacity warnings automatically.
Step 1 - Choose BAC Water Volume. For the full titration through 12 mg in a single draw, target 20 mg/mL (e.g. 20 mg vial + 1 mL BAC water). At 10 mg/mL, doses up to 10 mg fit within 100 units. The BAC water calculator recommends volumes based on your dose and syringe.
Step 2 - Reconstitute. Inject BAC water slowly against the inside glass wall. Retatrutide dissolves within 1-3 minutes of gentle swirling. Solution should be clear and colourless. See reconstituting peptides step by step.
Step 3 - Store. Refrigerate at 2-8°C. Stable for approximately 28 days. See how to store peptides.
| Factor | Retatrutide | Tirzepatide | Semaglutide |
|---|---|---|---|
| Receptor targets | Triple: GLP-1 + GIP + Glucagon | Dual: GIP + GLP-1 | GLP-1 only |
| Starting dose | 2 mg weekly | 2.5 mg weekly | 0.25 mg weekly |
| Maximum dose | 12 mg weekly | 15 mg weekly | 2.4 mg weekly |
| Phase 2 weight loss (48 wk) | 24.2% at 12 mg | 22.5% at 15 mg | 15.8% at 2.4 mg |
| Common vial sizes | 5, 10, 12, 20, 30 mg | 5, 10, 15, 30, 60 mg | 2, 3, 5, 10 mg |
| Regulatory status | Phase 3 (not yet approved) | FDA-approved | FDA-approved (Ozempic/Wegovy) |
Retatrutide's glucagon receptor activity adds thermogenesis and hepatic fat reduction that dual-agonists lack - but it also carries a different side effect profile. For compound-specific calculators, see the tirzepatide calculator and semaglutide calculator.
| Vial Size | At 2 mg/wk | At 4 mg/wk | At 8 mg/wk | At 12 mg/wk |
|---|---|---|---|---|
| 5 mg | 2.5 weeks | 1.25 weeks | - | - |
| 10 mg | 5 weeks | 2.5 weeks | 1.25 weeks | - |
| 12 mg | 6 weeks | 3 weeks | 1.5 weeks | 1 week |
| 20 mg | 10 weeks | 5 weeks | 2.5 weeks | ~1.7 weeks |
| 30 mg | 15 weeks | 7.5 weeks | 3.75 weeks | 2.5 weeks |
Reconstituted retatrutide lasts approximately 28 days. For price comparisons, use the cost-per-dose calculator.
| Tool | What It Does |
|---|---|
| Peptide Reconstitution Calculator | Standard calculator for all 30+ peptides |
| Tirzepatide Calculator | Tirzepatide-specific with 6-tier titration |
| Semaglutide Calculator | Semaglutide-specific with dose escalation |
| Cost-per-Dose Calculator | Compare retatrutide costs across vendors |
| BAC Water Calculator | Optimal BAC water volume for your vial and dose |
| Purity Comparison Tool | Compare lab-tested purity across brands |
At 6 mg/mL (12 mg vial + 2 mL BAC water): ~33 units. At 10 mg/mL: 20 units. At 20 mg/mL: 10 units. Use the calculator above with your specific vial and BAC water volume for exact numbers.
Phase 2 protocol: 2 mg weekly for weeks 1-4, 4 mg for weeks 5-8, 8 mg for weeks 9-12, and 12 mg from week 13 onward. Phase 3 TRIUMPH trials evaluate 4, 9, and 12 mg as maintenance targets.
2 mL produces 6 mg/mL - practical for starting doses but exceeds syringe capacity above 6 mg. 1 mL produces 12 mg/mL - covers doses up to 12 mg in 100 units. The BAC water calculator recommends volumes based on your dose and syringe.
Retatrutide is a triple-agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. Tirzepatide is a dual-agonist (GIP + GLP-1 only). Retatrutide's glucagon receptor activity adds thermogenesis and hepatic fat reduction. In Phase 2 trials, 12 mg retatrutide achieved 24.2% weight loss at 48 weeks - the highest reported for any injectable.
This calculator is for educational and research purposes only and does not constitute medical advice. Retatrutide is an investigational compound currently in Phase 3 clinical trials (TRIUMPH program) and is not yet approved by the FDA. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors, and is not affiliated with or endorsed by any manufacturer.