Retatrutide Pen Cartridge Overview
The retatrutide pen cartridge from MyGLP1Store is a 3 mL prefilled cartridge containing research-grade retatrutide (LY3437943) combined with vitamin B12, built to seat directly into the V3 auto-injection pen. The cartridge ships sealed and ready to load — there is no reconstitution step, no bacteriostatic water, and no vial transfer involved in using it with the pen. The V3 pen itself is sold separately.
Available Cartridge Options
| Total Retatrutide Content | SKU |
|---|---|
| 10 mg total content | FC-CART-RETA-10 |
| 20 mg total content | FC-CART-RETA-20 |
| 30 mg total content | FC-CART-RETA-30 |
| 40 mg total content | FC-CART-RETA-40 |
| 48 mg total content | FC-CART-RETA-48 |
Each option describes the total retatrutide content sealed inside that cartridge. These figures describe total cartridge content only, not an administration schedule or interval — select the option above to see current pricing and availability.
Why Researchers Choose the V3 Cartridge Format
- Prefilled, no reconstitution: the cartridge arrives sealed and ready to load into the pen — no bacteriostatic water or mixing step.
- Built for the V3 pen: designed specifically to seat into the V3 auto-injection pen for consistent handling in the lab.
- Retatrutide + B12 in one cartridge: a single prefilled cartridge contains both research-grade retatrutide and vitamin B12.
Specifications & Documentation
| Format | 3 mL prefilled cartridge |
| Contents | Retatrutide (LY3437943) and vitamin B12 |
| Compatibility | V3 auto-injection pen (sold separately) |
| Available options | 10 mg, 20 mg, 30 mg, 40 mg, 48 mg total content |
| Use | Laboratory and analytical research use only |
Retatrutide Pen Cartridge vs. V3 Pen Kit
| Pen Cartridge (this product) | V3 Pen Kit | |
|---|---|---|
| What it is | Prefilled cartridge containing retatrutide + B12 | Reusable auto-injection pen the cartridge loads into |
| Do you need both? | Yes — a cartridge requires a compatible pen | Yes — the pen requires a compatible cartridge |
| Sold separately? | Yes | Yes |
New to the V3 system? See the V3 Injection Pen Kit for the reusable pen and travel case.
Retatrutide Pen Cartridge vs. Retatrutide Vial
| Prefilled pen cartridge | Lyophilized vial | |
|---|---|---|
| Format | Prefilled solution in a sealed 3 mL cartridge | Freeze-dried powder in a sealed vial |
| Preparation | Loads directly into the V3 pen | Requires reconstitution before use |
| Added B12 | Yes | No |
| Compatible device | V3 auto-injection pen | Standard research syringe |
Prefer the lyophilized powder format instead? See the retatrutide vial listing.
What Is Retatrutide?
Retatrutide (research code LY3437943) is a synthetic peptide studied as a triple agonist at the GLP-1, GIP, and glucagon (GCGR) receptors. It is a subject of ongoing research into metabolic and endocrine signaling pathways. This cartridge supplies retatrutide in a prefilled solution format for use with the V3 auto-injection pen, alongside the lyophilized vial format also available on this site. For background on the compound’s mechanism and research literature, see the Retatrutide Research Guide.
Storage and Shipping
Keep the cartridge sealed in its original packaging until it is loaded into the pen in a controlled laboratory setting. Orders ship from the U.S. — choose Ground ($8), 2-Day ($15) or Next Day ($40) at checkout. Orders placed before 2:00 PM ET, Monday–Friday, are processed the same day.
Frequently Asked Questions
What is a retatrutide pen cartridge?
It is a sealed 3 mL cartridge prefilled with a retatrutide and vitamin B12 solution, built to load into the V3 auto-injection pen. The pen itself is sold separately.
Does this cartridge need to be reconstituted?
No. The cartridge ships prefilled. Nothing is added to it before it is loaded into the pen.
Which pen does this cartridge fit?
The V3 auto-injection pen. This cartridge is not designed for other pen models.
Do I need to buy the V3 pen separately?
Yes. This listing is for the cartridge only. See the V3 Injection Pen Kit if you do not already have a compatible pen.
What sizes are available?
Five total-content options: 10 mg, 20 mg, 30 mg, 40 mg, and 48 mg. Select an option above to see current pricing and availability.
Does the cartridge contain vitamin B12?
Yes, the cartridge contains vitamin B12 in addition to retatrutide.
How is this different from the retatrutide vial?
The vial is a lyophilized powder that requires reconstitution; this cartridge is a prefilled solution built for the V3 pen and includes added B12. See the comparison table above.
Can this cartridge be used in a different auto-injection pen?
No. It is built specifically for the V3 auto-injection pen.
How is this cartridge shipped?
Orders ship from the U.S. with three options at checkout: Ground ($8), 2-Day ($15) or Next Day ($40). Orders placed before 2:00 PM ET, Monday–Friday, are processed the same day; orders ship Monday through Friday only.
What is retatrutide?
Retatrutide (LY3437943) is a peptide studied as a triple agonist at the GLP-1, GIP, and glucagon receptors. See the Retatrutide Research Guide for more detail.
Is this product intended for human use?
No. This cartridge is supplied solely for laboratory and analytical research and is not intended for human or veterinary use, administration, diagnosis, treatment, or prevention of disease.
Related & Compatible Products
- V3 Injection Pen Kit with Travel Case — the reusable pen this cartridge is built for.
- Retatrutide (LY3437943) Vial — the lyophilized powder format.
- Tirzepatide Pen Cartridge — another V3-compatible prefilled cartridge.
- Semaglutide Pen Cartridge — another V3-compatible prefilled cartridge.






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