Research Overview
This page covers the two-vial stack people call the LEAN blend, reta/cag, or the 4-receptor stack. CoreVials sells separate vials, not a 12.5 mg / 2.5 mg pre-blend. Mix each peptide on its own. Draw with separate syringes. Same research day, different preparation areas.
Retatrutide covers three pathways: GLP-1 (appetite), GIP (insulin signaling), and glucagon (energy use). Cagrilintide covers the missing amylin fullness signal. Together the model is four pathways, not two copies of the same one.
Do not add semaglutide or tirzepatide on top. Retatrutide already covers GLP-1 (and GIP). Extra incretin compounds add overlap, not a new pathway.
| Parameter | Research model |
|---|---|
| Format | Two vials (not one pre-blend) |
| Retatrutide mix | 10 mg/mL (10 mg + 1 mL, 20 mg + 2 mL, or 30 mg + 3 mL BAC) |
| Cagrilintide mix | 5 mg/mL (10 mg + 2 mL, or 5 mg + 1 mL BAC) |
| Pattern | Once weekly for both, after a Retatrutide-only start |
| Reta start | 0.5 mg (5 units at 10 mg/mL) |
| Cag start | 0.25 mg (5 units at 5 mg/mL), added after about 8 weeks |
Standalone charts: Retatrutide beginner guide and Cagrilintide protocol.
What Each Compound Covers
- Retatrutide: triple agonist. GLP-1 slows the gut and quiets appetite. GIP supports insulin signaling. Glucagon raises energy use.
- Cagrilintide: long-acting amylin analog. Fullness through the hindbrain, a different channel than GLP-1.
- Why they get paired: Retatrutide does not hit amylin. Cagrilintide fills that gap. Both also slow gastric emptying, so GI load can stack. That is why the example starts Retatrutide alone at 0.5 mg, then adds Cagrilintide at 0.25 mg.
Mix Math for Each Vial
Pick one mix per vial and keep it. U-100 syringe: 100 units = 1 mL.
Retatrutide to 10 mg/mL
| Vial | BAC water | Concentration | 0.5 mg | 1 mg | 2 mg |
|---|---|---|---|---|---|
| 10 mg | 1.0 mL | 10 mg/mL | 5 units | 10 units | 20 units |
| 20 mg | 2.0 mL | 10 mg/mL | 5 units | 10 units | 20 units |
| 30 mg | 3.0 mL | 10 mg/mL | 5 units | 10 units | 20 units |
2.5 mg = 25 units. 3 mg = 30 units. 4 mg = 40 units. Same unit math on every vial at 10 mg/mL.
Cagrilintide to 5 mg/mL
| Vial | BAC water | Concentration | 0.25 mg | 0.5 mg | 1.0 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 5 mg | 1.0 mL | 5 mg/mL | 5 units | 10 units | 20 units | 48 units |
| 10 mg | 2.0 mL | 5 mg/mL | 5 units | 10 units | 20 units | 48 units |
1.7 mg = 34 units at 5 mg/mL.
Cagrilintide is handling-sensitive. Run BAC water down the glass wall. Roll or swirl. Do not shake. Discard if cloudy.
Measurement Examples
This example uses the same starts as the standalone charts: Retatrutide 0.5 mg, Cagrilintide 0.25 mg. Hold each step 4 weeks. Add Cagrilintide only after the first 8 weeks of Retatrutide. Step back if GI is loud.
| Phase | Weeks | Retatrutide | Units at 10 mg/mL | Cagrilintide | Units at 5 mg/mL |
|---|---|---|---|---|---|
| Reta start | 1-4 | 0.5 mg | 5 units | not started | — |
| Reta step | 5-8 | 2 mg | 20 units | not started | — |
| Add Cag | 9-12 | 2 mg hold | 20 units | 0.25 mg | 5 units |
| Dual 1 | 13-16 | 2.5 mg | 25 units | 0.5 mg | 10 units |
| Dual 2 | 17-20 | 3 mg | 30 units | 1.0 mg | 20 units |
| Dual 3 | 21-24 | 4 mg | 40 units | 1.7 mg | 34 units |
| Hold | 25+ | 4 mg | 40 units | 2.4 mg | 48 units |
Weeks 1-4 can use 1 mg (10 units) instead of 0.5 mg if that is the other beginner-chart option. Weeks 5-8 can use 1.5 mg (15 units) instead of 2 mg. After week 17, Retatrutide can still step +0.5 to 1 mg every 4 weeks if needed. 12 mg is the published high end, not a starter mark.
Mix Steps (each vial)
- Gather the peptide vial, bacteriostatic water, alcohol swabs, and a sterile U-100 syringe.
- Wipe both rubber stoppers with alcohol and let dry.
- Draw the planned BAC volume.
- Introduce water slowly along the glass wall, not onto the powder.
- Swirl or roll. Do not shake (especially Cagrilintide).
- Label compound, concentration, and mix date. Refrigerate at 2-8 C.
- Plan around 28-30 days after mixing with clean technique.
Research Cycle Pattern
- Weeks 1-8: Retatrutide only, starting at 0.5 mg. Confirm GI tolerance before adding the second peptide.
- Week 9 onward: add Cagrilintide at 0.25 mg, hold Retatrutide steady that block.
- Cagrilintide then follows its own weekly ladder: 0.25, 0.5, 1.0, 1.7, then 2.4 mg hold.
- Raise one compound per block when GI is already high.
- Same day is common. Different preparation areas. Separate syringes. Do not combine in one syringe.
Handling Notes
- Use a new sterile U-100 syringe for each draw.
- Rotate preparation areas (abdomen, thigh, flank).
- Both compounds slow gastric emptying. GI observations (nausea, constipation) can stack during dual step-ups.
- Do not pair this stack with semaglutide or tirzepatide.
- Pre-blend vials from other suppliers (often 12.5 mg Retatrutide + 2.5 mg Cagrilintide) lock a 5:1 ratio. That math is not this page. Confirm the label before mixing.
How This Works
Retatrutide is studied as a triple agonist at GLP-1, GIP, and glucagon receptors. Cagrilintide is studied as a long-acting amylin analog. Amylin signals fullness in the hindbrain. The pairing idea comes from amylin-plus-incretin research (CagriSema uses Cagrilintide + semaglutide). Swapping semaglutide for Retatrutide is a pathway-coverage model. The exact two-compound pair does not have its own published combo trial.
Cheat sheet: Retatrutide + Cagrilintide LEAN Blend.
Shop: LEAN Blend kit (two separate vials). Standalone: Retatrutide and Cagrilintide.
Storage and Handling
- Lyophilized: cool, dry, dark. Freeze at about -20 C for longer holding.
- After mixing: refrigerate at 2-8 C. Do not freeze. Protect from light. Use within about 28-30 days.
- Discard cloudy or particulate solution.
Research Use Only
For educational / laboratory research reference only. Sold for laboratory research only. Not for human or animal consumption. Not medical advice.
