Guide

The “retatrutide pen”: what you need to know

Reviewed 22 October 2026 · How we research

Searches for “retatrutide pen” have exploded. The short answer: Eli Lilly does not sell one, because retatrutide is not yet approved anywhere.

There is no licensed retatrutide pen

Retatrutide is in phase 3 trials. Lilly's trial supplies are not sold to the public, and no regulator — including the MHRA — has approved a retatrutide product. Any “retatrutide pen”, “Reta pen” or “Reta jab” for sale is therefore an unlicensed product made by an unknown third party.

What is being sold

Most “Reta pens” are reusable or disposable cartridge pens that have been pre-filled with reconstituted peptide by the seller. The risks are:

• Unknown content and concentration — there is no way to verify what is in a pre-filled cartridge.
• Sterility — filling cartridges outside a sterile pharmaceutical environment risks contamination.
• Stability — reconstituted retatrutide has unknown stability once mixed.
• Legality — supplying a product for human injection without a licence is an offence in the UK.

Research vials vs pens

Research suppliers sell retatrutide as a sealed lyophilised powder with a batch-specific certificate of analysis. Because it is sealed, its identity and purity can be checked against the COA — see how to read a COA. Research vials are sold strictly for laboratory use, not for human use.

Retatrutide price in the UK

Because retatrutide has no licensed form, there is no NHS or pharmacy price. Research-grade vial prices are shown on our Retatrutide UK page. Pre-filled pens typically sell at a substantial markup to the vial cost they contain.