Retatrutide Dosage Calculator & Chart
Printed on the vial label.
1 mg = 1,000 mcg. Enter your own prescribed or planned amount.
Draw on your syringe
20units= 0.2 mL
- Concentration
- 10,000mcg/mL
- Each unit
- 100 mcg
- Doses per vial
- 10
- Vial lasts
- 10weeks
Want a rounder number to draw?
Show the math
- Concentration = 20 mg × 1,000 ÷ 2 mL = 10,000 mcg/mL
- Volume = 2,000 mcg ÷ 10,000 mcg/mL = 0.2 mL
- Units = 0.2 mL × 100 = 20 units (U-100: 100 units = 1 mL)
The pre-filled dose (2 mg) is an example input so the calculator shows a result. It is not a recommendation.
Retatrutide dosage chart (in units)
Units to draw for each dose at your current mix (20 mg vial + 2 mL water). Dose escalation used for the 12 mg group in the phase 2 obesity trial (Jastreboff et al., NEJM 2023): start at 2 mg weekly and step up about every 4 weeks. Investigational — there is no approved label or dose.
| Period | Dose | Units (U-100) | mL |
|---|---|---|---|
| Weeks 1–4 (trial start) | 2 mg | 20 | 0.2 |
| Weeks 5–8 | 4 mg | 40 | 0.4 |
| Weeks 9–12 | 8 mg | 80 | 0.8 |
| Week 13+ (top dose studied) | 12 mg | 120>1 mL | 1.2 |
Retatrutide units chart
Units to draw on a U-100 syringe for common Retatrutide vial sizes, each mixed with 2 mL of bacteriostatic water. Change the water in the calculator and this table updates.
| Dose | 5 mg vial | 10 mg vial | 15 mg vial | 20 mg vial | 30 mg vial |
|---|---|---|---|---|---|
| 1 mg | 40 | 20 | 13.3 | 10 | 6.7 |
| 2 mg | 80 | 40 | 26.7 | 20 | 13.3 |
| 4 mg | >100 | 80 | 53.3 | 40 | 26.7 |
| 6 mg | >100 | >100 | 80 | 60 | 40 |
| 8 mg | >100 | >100 | >100 | 80 | 53.3 |
| 12 mg | >100 | >100 | >100 | >100 | 80 |
Values are units on a U-100 insulin syringe (100 units = 1 mL). ">100" means the dose does not fit in a 1 mL syringe at this dilution.
About Retatrutide
Retatrutide is an investigational once-weekly agonist of the GIP, GLP-1 and glucagon receptors developed by Eli Lilly for obesity and related conditions.
Regulatory status: Investigational drug — not FDA-approved at the time of writing. Check Drugs@FDA for current status. Vials sold online outside clinical trials are unregulated.
Also searched as: reta, LY3437943.
How to reconstitute Retatrutide
- Wash your hands and let the vial reach room temperature.
- Wipe the rubber stoppers of the peptide vial and the bacteriostatic water with an alcohol pad.
- Draw the planned amount of bacteriostatic water (for example 2 mL — that is 200 units on a 1 mL syringe).
- Inject the water slowly down the inside wall of the vial, not directly onto the powder.
- Gently swirl or roll the vial until the powder dissolves. Do not shake.
- Label the vial with the date and the concentration shown by the calculator, and store it as the product label directs (reconstituted peptides are normally kept refrigerated).
These are general handling steps, not medical instructions. If your product came with instructions from a pharmacy or prescriber, follow those.
What you need
Bacteriostatic water
Sterile water with 0.9% benzyl alcohol, used to dissolve the powder.
U-100 insulin syringes
0.3 mL syringes are easiest to read for small doses; 1 mL for larger ones.
Alcohol prep pads
Wipe the vial stopper before every draw.
Sharps container
For safe disposal of used needles.
- Which syringes and supplies to buy →
Retatrutide calculator FAQ
How many units is 2 mg of Retatrutide?
+
It depends on how much water you add. With a 20 mg vial mixed with 2 mL of bacteriostatic water, the concentration is 10,000 mcg/mL, so 2 mg is 0.2 mL = 20 units on a U-100 insulin syringe. With a 30 mg vial and the same 2 mL of water it is 13.3 units.
How much water should I add to a 20 mg Retatrutide vial?
+
The water volume does not change the total amount of Retatrutide; it only sets the concentration. Common choices are 1–3 mL. With 2 mL, each unit on a U-100 syringe holds 100 mcg. Pick a volume that makes your dose easy to read on the syringe — the calculator above suggests volumes that land on round numbers.
How many doses are in a 20 mg vial of Retatrutide?
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At 2 mg per injection, a 20 mg vial contains 10 full doses. The amount of water you add does not change this number.
What is the Retatrutide dosage schedule?
+
Dose escalation used for the 12 mg group in the phase 2 obesity trial (Jastreboff et al., NEJM 2023): start at 2 mg weekly and step up about every 4 weeks. Investigational — there is no approved label or dose. The dosage chart above converts each step into units for your vial. Follow your prescriber's instructions.
Is Retatrutide approved?
+
Investigational drug — not FDA-approved at the time of writing. Check Drugs@FDA for current status. Vials sold online outside clinical trials are unregulated.
Sources
Calculator math: concentration = vial mg × 1,000 ÷ water mL; units = dose ÷ concentration × 100 (U-100 syringe). Data and references last reviewed 2026-10-10.