Buy Retatrutide 40mg Auto-Injection Pen — Pre-Order
The Retatrutide 40mg Auto-Injection Pen is the newest format in our GLP-1 research peptide lineup: a prefilled pen containing 40 mg total retatrutide (LY3437943), ready to use straight out of the box. Pre-order today to reserve a pen from the first batch. Pens begin shipping October 25, 2026, and supply is limited.
Why Pre-Order Now
- Limited first batch. Pre-orders are filled first come, first served. Once this allocation is gone, the next batch date is not guaranteed.
- Lock in today’s price. Reserve your pen at the pre-order price before release.
- Guaranteed spot in line. Your pen is set aside for you as soon as your order is placed.
- Ships on release. Pre-orders go out starting October 25 with tracking.
What You Get
| Product | Retatrutide Auto-Injection Pen |
| Total content | 40 mg retatrutide |
| Format | Prefilled auto-injection pen |
| Compound | Retatrutide (LY3437943), a triple GIP/GLP-1/glucagon receptor agonist |
| Availability | Pre-order — ships October 25, 2026 |
| Supply | Limited first batch |
Pen vs. Vial vs. Cartridge
| Format | What it involves |
|---|---|
| 40mg Auto-Injection Pen (this listing) | Complete prefilled pen. Nothing to mix, nothing else to buy. |
| Retatrutide lyophilized vial | Powder that must be reconstituted with bacteriostatic water before use. |
| Retatrutide pen cartridge | Prefilled cartridge that requires the V3 auto-injection pen, sold separately. |
Pre-Order Shipping
Pre-orders begin shipping October 25, 2026, using the shipping method you choose at checkout. We ship to U.S. addresses only, Monday through Friday. If you also need in-stock items right away, place those on a separate order so they are not held for the pen release.
Retatrutide Pen for Sale — 40mg Prefilled Injection Pen
Looking to buy a retatrutide pen online? This retatrutide injection pen comes prefilled with 40 mg total retatrutide, so there is no powder to reconstitute, no bacteriostatic water and no vial-to-syringe transfer. It is a complete, standalone retatrutide pen injector — add it to your cart, check out, and your pen is reserved from the first batch.
Retatrutide Pen Price
The retatrutide pen price is listed per pen at the top of this page, for 40 mg total retatrutide in one prefilled auto-injector. Pre-order pricing is locked in when you check out, even if the price changes after release.
Where to Buy a Retatrutide Pen Online
- U.S. store, U.S. shipping. Every order ships to U.S. addresses with tracking, Monday through Friday.
- Your choice of speed. Pick Ground, 2-Day or Next Day at checkout.
- COAs on request. Ask for the certificate of analysis for this product and we will send it.
- Earn rewards. Registered customers earn loyalty points on every order.
About Retatrutide
Retatrutide (LY3437943) is a triple agonist of the GIP, GLP-1 and glucagon receptors. Retatrutide is an investigational compound developed by Eli Lilly and is not FDA-approved. Prefer a different format? Shop retatrutide vials, retatrutide pen cartridges for the V3 pen, or the Tirzepatide 40mg Auto-Injection Pen. See every option in GLP-1 research peptides.
Frequently Asked Questions
When will my Retatrutide pen ship?
Pre-orders begin shipping October 25, 2026. You will receive tracking when your order ships.
Is the pen prefilled?
Yes. The pen arrives prefilled with 40 mg total retatrutide. There is no reconstitution step.
Do I need the V3 pen?
No. The V3 pen is for our pen cartridges. This auto-injection pen is a complete, standalone unit.
How many pens are available?
Supply for the first batch is limited and pre-orders are filled in the order they are placed. Pre-order now to secure yours.
How much does a retatrutide pen cost?
The current price for the 40mg retatrutide pen is shown at the top of this page. One pen contains 40 mg total retatrutide.
Where can I buy a retatrutide pen?
Right here. MyGLP1Store sells the retatrutide 40mg injection pen online and ships to U.S. addresses with tracking.
Is this pen made by Eli Lilly?
No. Retatrutide is still in clinical trials and there is no Lilly-branded retatrutide pen on the market. This pen is sold by MyGLP1Store and is not made, sold or endorsed by Eli Lilly.
Reconstitution & Research Reference
Sourced direct from the manufacturer. No distributors, no repackaging, no middlemen.
Every order ships with free bacteriostatic water for reconstitution. Typical laboratory workflow: reconstitute the lyophilized peptide with bacteriostatic water, calculate the concentration per vial, and store according to the product storage guidance.
Open the Reconstitution Calculator
About the free bacteriostatic water
For laboratory research use only. Not for human consumption.
Read the BAC water concentration and storage guide · Buy additional BAC water for peptides
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