Metabolic
GLP-3 RT (Retatrutide)
Retatrutide
Three-pathway metabolic research compound
Quick answer
A 30 mg vial with 3 mL of water makes 10 mg/mL. A 1 mg dose is 10 units. Once a week, stepped up every 4 weeks.
- Mix it
- 30 mg vial + 3 mL water
- Draw
- About 10 units on a U-100 syringe
- How often
- Once a week, same day each week
- How it is given
- Under the skin, same day each week.
- How long it lasts
- About 6 days, so once a week.
- Store it
- Refrigerate after mixing. Use within about 4 weeks.
What it is
Full name: Retatrutide. Most people write it as GLP-3 RT.
Retatrutide acts on three pathways: GLP-1, GIP, and glucagon. The third pathway is linked to energy burn, which is what separates it from tirzepatide in research.
What it is studied for
- Body weight
- Appetite control
- Liver fat
- Metabolic rate
These are things researchers study. They are not promised results.
Dosing at a glance
These are the amounts used most often in research. Always start at the low end.
- Vial size
- 10 mg to 30 mg
- Dose range
- 1 mg to 12 mg per week, increased slowly
- How often
- Once a week, same day each week
- Cycle length
- Long term, dose stepped up every 4 weeks
- Mix with
- Bacteriostatic water (also called BAC water or reconstitution solution).
- Storage
- Refrigerate after mixing. Use within about 4 weeks.
Week by week
A common way researchers step the dose up. Stay at each step until it feels easy.
| When | Dose | Notes |
|---|---|---|
| Weeks 1-4 | 1-2 mg weekly | Start low. This one is strong. |
| Weeks 5-8 | 4 mg weekly | Only if side effects are mild. |
| Weeks 9-12 | 6-8 mg weekly | Hold if nausea returns. |
| Week 13+ | Up to 12 mg weekly | Most people never need the top dose. |
This is a reference schedule, not a prescription. Start at the lowest step.
Mixing it
A common setup for GLP-3 RT is a 30 mg vial with 3 mL of bacteriostatic water.
That makes 10 mg per mL. A 1 mg dose is about 10 units on a standard insulin syringe.
Bacteriostatic water is all you need here. Acetic acid is only for powders that will not dissolve. See the mixing guide.
Open this in the calculatorWhat to watch for
- Nausea and stomach upset
- Raised heart rate in some people
- Loss of muscle if protein intake is low
Stop and speak to a clinician if anything feels wrong. See the safety page.
Common questions
How is it different from tirzepatide?
It adds a third pathway linked to burning energy, not just appetite.
Why does my heart feel faster?
Reported in research at higher doses. Drop back a step and check with a clinician.
Can I switch from tirzepatide?
People do, but restart low. The doses are not the same.