Metabolic
Retatrutide
per administration
A human trial worked out how much to take and how often, so a dosing schedule is shown.
Quick start
Retatrutide at a glance — the figures, plus how it's commonly run. Reference only, not medical advice.
- Typical dose
- 1–12 mg per administration
- How often
- Once a week
- Where
- Subcutaneous — abdomen, thigh, or upper arm Sites and rotation
- Timing
- Once weekly on the same day.
- What people report
- Early appetite change is commonly reported; amounts are escalated slowly in trials.
- Time to steady level
- ~30.0 days — about five half-lives
- Storage
- Dry vial kept cold and dark; a mixed vial in the fridge at 2–8 °C. Details
- Cycle length
- titrated over months
- Break between
- n/a — titrated, not cycled Why
A research and community reference, not medical advice. Figures are descriptive, vary between sources, and are not a recommendation for use.
Key properties
Molecular reference data.
- Formula
- C221H342N46O68
- Mol. weight
- 4,731.33 Da
- CAS
- 2381089-83-2
External references
Work out your draw
These numbers are a starting point — change any of them.
Vial label
Copy this into your label printer.
Published research contexts for Retatrutide describe 1–12 mg per administration. Descriptive only, not a recommendation.
Dosing schedule
How Retatrutide is commonly stepped up, for reference only.
These are commonly-discussed research protocols shared for educational reference. This is not medical advice and is not a substitute for guidance from a qualified professional.
| Phase | Amount | Frequency | Route |
|---|---|---|---|
| Weeks 1–4Conservative start; most gastrointestinal effects appear here. | 0.5 mg | Once weekly | SubQ |
| Weeks 5–8 | 1 mg | Once weekly | SubQ |
| Weeks 9–12 | 2 mg | Once weekly | SubQ |
| Weeks 13–16 | 4 mg | Once weekly | SubQ |
| Weeks 17–20 | 8 mg | Once weekly | SubQ |
| Week 21+Highest amount reported in the study; escalate only if lower steps are tolerated. | 12 mg | Once weekly | SubQ |
What it can be combined with
How Retatrutide is commonly discussed alongside other peptides and drugs.
Educational reference on commonly-discussed combinations, not medical advice. Combining compounds can change how each behaves — read this as a prompt to research, not a clearance.
- SemaglutideBoth drive GLP-1 receptor agonism, so running them together doubles the same mechanism rather than adding a new one.Avoid combination
- TirzepatideOverlapping GLP-1 receptor agonism; stacking incretin agonists compounds gastrointestinal load without adding a mechanism in research reports.Avoid combination
- CagrilintideAmylin-analog co-administration has been studied, but it intensifies the same appetite and gastrointestinal effects — escalate slowly if combined.Use caution
- InsulinAdditive glucose-lowering; research reports note a raised hypoglycemia signal, warranting closer glucose monitoring.Monitor combination
- Oral medicationsDelayed gastric emptying can slow oral absorption; separating oral doses from injection day is the usual discussion point.Requires timing
- MetforminCommonly co-administered in studies with no adverse interaction reported.Commonly combined
Modelled level — once a week
1× is the peak after a single dose.
- Steady-state peak
- 1.74× single dose
- Time to steady state
- 30.0days
- Administrations
- 1/ week
Read off the modelled curve, not an even-interval formula
About five half-lives
Where these numbers come from
- Jastreboff AM et al., NEJM 2023Phase-2 obesity study of retatrutide (LY3437943); weekly escalation to 12 mg over ~24 weeks in study participants.
- GLP-1 receptor agonist class pharmacokineticsLong fatty-acid-conjugated GLP-1 agonists carry multi-day elimination half-lives, supporting once-weekly administration.