The triple-agonist peptide generating the most buzz in weight loss. Calculate your dose and understand the titration from 0.5 mg to 12 mg.
Pre-filled with typical retatrutide values. Adjust to match your vial and protocol.
Retatrutide (development code LY3437943) is an investigational triple-agonist peptide developed by Eli Lilly and Company. Unlike semaglutide (which targets only GLP-1) or tirzepatide (which targets GLP-1 and GIP), retatrutide activates three receptors simultaneously: GLP-1, GIP, and the glucagon receptor.
This triple mechanism is significant because the addition of glucagon receptor agonism may increase energy expenditure and promote fat oxidation on top of the appetite-suppressing effects of GLP-1 and GIP. In phase 2 clinical trials, participants receiving the highest doses of retatrutide experienced substantial weight reduction over 48 weeks.
Retatrutide is typically administered once weekly via subcutaneous injection. Most protocols follow a gradual dose escalation to minimize gastrointestinal side effects. Below is a common titration schedule based on published clinical trial protocols:
| Period | Weekly Dose | Notes |
|---|---|---|
| Weeks 1-4 | 0.5 mg | Starting dose; assess tolerability |
| Weeks 5-8 | 1.0 mg | First escalation |
| Weeks 9-12 | 2.0 mg | Second escalation |
| Weeks 13-16 | 4.0 mg | Third escalation |
| Weeks 17-20 | 8.0 mg | Fourth escalation |
| Week 21+ | 12.0 mg | Maintenance dose (highest studied) |
Ready to calculate? Use the calculator above or our full calculator with syringe visualization.
Retatrutide comes as a lyophilized (freeze-dried) powder that must be reconstituted with bacteriostatic water before injection. The process is the same as for other peptides:
For a detailed step-by-step guide with visuals, see our complete peptide reconstitution guide.
The most commonly reported side effects in clinical trials were gastrointestinal in nature and generally dose-dependent. Many participants reported that side effects improved over time as the body adjusted to the medication.
Before reconstitution: Store lyophilized (powder) retatrutide in a cool, dry place. Refrigeration is ideal but not always required for short-term storage of unreconstituted peptides. Keep away from direct sunlight and heat.
After reconstitution: Store the reconstituted vial upright in a refrigerator at 36-46°F (2-8°C). Do not freeze. The solution typically remains stable for 4-6 weeks. Always swab the vial stopper with an alcohol pad before drawing a dose.
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