> Note: PeptIQ is not a medical provider. This article is educational only. Retatrutide is investigational. Discuss any peptide use with a qualified clinician.
Answer first: Add bacteriostatic water to your vial, swirl (never shake), refrigerate, then start at a low weekly dose and step up only when side effects are manageable. Concentration = labeled milligrams ÷ BAC milliliters. On a U-100 syringe, 100 units = 1 mL.
This page is the definitive beginners hub: reconstitution tables for 5mg / 10mg / 20mg vials, unit math, a 12-week titration chart, side-effect phases, and when to hold a dose.
Understanding Your Vial Size
Retatrutide commonly comes in three vial sizes:
| Vial Size | Best For | Typical Use |
|---|---|---|
| 5mg | Beginners, low-dose protocols | 5-10 weeks at starter doses |
| 10mg | Standard use | 8-16 weeks depending on dose |
| 20mg | Experienced users, higher doses | Extended protocols or higher weekly doses |
For dedicated 10mg / 20mg listing math, see the companion Retatrutide 20 mg vial reconstitution guide. Run any vial in the reconstitution calculator.
How Much BAC Water to Add
The amount of bacteriostatic water you add determines your concentration.
> Example only, not your vial. The tables below are illustrative dilution charts for labeled listing sizes. Your vial mass and chosen water volume decide the real unit counts. Check the label and run the reconstitution calculator.
5mg Vial (Most Common for Beginners)
| BAC Water | Concentration | 0.5mg Dose | 1mg Dose | 2mg Dose |
|---|---|---|---|---|
| 1ml | 5mg/ml | 10 units | 20 units | 40 units |
| 2ml | 2.5mg/ml | 20 units | 40 units | 80 units |
Example dilution often discussed for a 5mg vial: 1ml of BAC water → 5mg/ml:
- 10 units = 0.5mg
- 20 units = 1.0mg
- 30 units = 1.5mg
10mg Vial
| BAC Water | Concentration | 1mg Dose | 2mg Dose | 2.5mg Dose |
|---|---|---|---|---|
| 2ml | 5mg/ml | 20 units | 40 units | 50 units |
| 1ml | 10mg/ml | 10 units | 20 units | 25 units |
Example dilution often discussed for a 10mg vial: 2ml of BAC water (5mg/ml), keeping dose math consistent with the 5mg/1ml example.
20mg Vial
| BAC Water | Concentration | 1mg Dose | 2mg Dose | 4mg Dose |
|---|---|---|---|---|
| 2ml | 10mg/ml | 10 units | 20 units | 40 units |
| 4ml | 5mg/ml | 20 units | 40 units | 80 units |
Example dilution often discussed for a 20mg vial: 2ml of BAC water (10mg/ml):
- 10 units = 1mg
- 20 units = 2mg
- 50 units = 5mg
Step-by-Step Reconstitution Process
- Gather supplies: BAC water, alcohol swabs, insulin syringe, vial
- Clean both vials: Wipe the rubber stoppers with alcohol swabs
- Draw BAC water: Pull your chosen amount into the syringe
- Inject slowly: Add the water to the peptide vial, aiming it at the glass wall—not directly onto the powder
- Swirl gently: Roll the vial between your palms. Never shake.
- Wait: Let it sit 5-10 minutes. Solution should be crystal clear.
- Store: Refrigerate immediately. Good for 28-30 days once reconstituted.
If it's cloudy or won't dissolve: Let it sit longer. Try gentle warming (under your arm or in lukewarm water). If still cloudy after 30 minutes, contact your source.
12-Week Beginner Titration Chart
Retatrutide is a triple agonist (GLP-1, GIP, glucagon). Starting too high is the #1 beginner mistake. The conservative chart below is what most research-community write-ups use.
| Weeks | Weekly Dose | What to Expect |
|---|---|---|
| 1–2 | 0.25mg | Minimal effects. Mild appetite decrease possible. GI calm. |
| 3–4 | 0.5mg | First noticeable food noise reduction. Possible mild nausea. |
| 5–6 | 1mg | Clear satiety signal. Nausea is common — slow eating, small portions. |
| 7–8 | 1.5mg | Meaningful caloric deficit starting to compound. |
| 9–10 | 2mg | Strong GLP-1 + glucagon effect. Fatigue on injection day possible. |
| 11–12 | 2–3mg | Evaluate here. Many people stay at 2mg for months. |
Key rule: Only increase if you have zero or manageable side effects at your current dose. Staying at 1mg for an extra 3–4 weeks is fine.
Coming off semaglutide or tirzepatide with decent tolerance, some people start at 0.5mg instead of 0.25mg. Still do not jump to 1–2mg on week one.
Alternate "standard" ramp (if 0.25mg is unavailable)
| Week | Weekly Dose | Notes |
|---|---|---|
| 1-2 | 0.5mg | Assess tolerance |
| 3-4 | 1.0mg | Most notice appetite changes here |
| 5-6 | 1.5mg | Solid fat loss begins |
| 7-8 | 2.0mg | Sweet spot for many |
| 9+ | 2.0-2.5mg | Adjust based on response |
Side Effects by Phase
Early phase (weeks 1-4)
- Mild nausea — most common 24-48 hours post-injection. Eat slowly; avoid huge high-fat meals.
- Reduced hunger — mechanism working. Prioritize protein (about 1.6–2g/kg bodyweight).
- Fatigue — injection-day low energy usually fades by week 4–6.
Mid phase (weeks 5-8)
- GI slowdown / constipation — magnesium glycinate, water, fiber.
- Nausea on dose bumps — often clears within 5–7 days at the new dose.
- Injection site reactions — mild redness or bump; rotate belly, thigh, upper arm.
Later phase (weeks 9-12+)
- Plateau windows — 2–3 week scale stalls are common; track waist and photos too.
- Muscle loss risk — under a deep deficit, protein + resistance training matter.
When to Hold a Dose
Hold (do not increase; consider reducing) if:
