Retatrutide Pen 40mg (Reta Pen)

Retatrutide (R-Tide) is a synthetic triple-agonist peptide investigated in laboratory research into the GLP-1, GIP and glucagon receptor pathways. This pre-mixed pen format supplies 40 mg of Retatrutide in a 3 ml stabilised cartridge, eliminating the need for manual reconstitution and reducing handling variability between experiments.

The pH-balanced, stabilised formulation is prepared under controlled conditions and dispensed through a precision dial mechanism graduated at 15 clicks per 2 mg, allowing repeatable volumetric dispensing for research protocols.

Store refrigerated at 2–8 °C and protect from light. Once in use, keep the cartridge upright and observe aseptic handling practice. This product is supplied strictly for laboratory research use only and is not for human or veterinary use.

Key takeaways

• 40 mg of retatrutide in one sealed 3 ml cartridge, supplied pre-mixed. There is no reconstitution step and nothing to add.
• Dial graduated at 15 clicks per 2 mg, so a given click count displaces the same volume on the first dispense and the last.
• A triple agonist — it acts at the GLP-1, GIP and glucagon receptors, where most peptides in this class act at one or two.
• CAS 2381089-83-2, developmental code LY3437943.
• Held in UK stock and dispatched the same working day on orders placed before 2pm, cold-packed in plain outer packaging.
• Supplied for laboratory research use only, and not for human or veterinary use.

What is retatrutide?

Retatrutide is a synthetic triple agonist peptide, acting at the GLP-1, GIP and glucagon receptors. That third receptor is what separates it from the dual agonists: most GLP peptides in the research market act on one or two, and retatrutide is studied because it engages all three.

Laboratory interest is in metabolic signalling pathways. It is supplied here strictly as an in-vitro research compound.

How retatrutide works: the GLP-1, GIP and glucagon receptors

Retatrutide is a single synthetic peptide that acts as an agonist at three separate receptors. All three belong to the class B family of G-protein-coupled receptors, and each is normally activated by a different endogenous hormone:

• GLP-1 receptor — the receptor for glucagon-like peptide-1.
• GIP receptor — the receptor for glucose-dependent insulinotropic polypeptide.
• Glucagon receptor — the receptor for glucagon.

Most peptides of this type are mono-agonists or dual agonists: they engage one receptor, or two. Engaging all three from a single molecule is what places retatrutide in a different group within the class, and it is the reason it is described as a triple agonist rather than a dual one.

Retatrutide was assigned the USAN stem -tide in 2022 — the stem reserved for peptides.

This section describes receptor pharmacology and nothing else. Peptide Global publishes no outcome, efficacy or physiological-effect information for this compound, and makes no claim about what the mechanism above produces in any organism.

Retatrutide is registered under CAS number 2381089-83-2 and the developmental code LY3437943, listed in the PubChem and ChEMBL registries as CHEMBL5095485. Those identifiers, the cartridge strength and the dial graduation are all listed in the specifications table below.

Reta pen: the same thing under a shorter name

Most people searching for this product type "reta pen" rather than the full compound name, and the two mean the same thing. A reta pen is a pre-filled retatrutide cartridge in a dial-dosing pen, as opposed to lyophilised powder in a vial.

Our reta pen is branded R-Tide, which is the same preparation: 40 mg of retatrutide in a 3 ml pre-mixed cartridge.

Retatrutide 40 mg pen: format and dial graduation

The cartridge holds 40 mg in 3 ml, dispensed by dial at 15 clicks per 2 mg. Because the concentration is fixed at manufacture, a given number of clicks corresponds to the same volume every time, which is the practical argument for a pen over a vial.

Vials have to be reconstituted with bacteriostatic water before use, and every reconstitution adds variables: how much water, how well mixed, how long at room temperature. A pre-mixed cartridge removes that step entirely.

Reta pen 20 mg and 40 mg: what the strengths mean

Reta pens are sold in the research market at more than one cartridge strength, 20 mg and 40 mg being the common ones, usually in the same 3 ml volume. The compound is identical; what changes is concentration. A 40 mg cartridge holds twice the retatrutide of a 20 mg cartridge in the same volume of solution, so a given volume dispensed carries twice the mass.

We supply the 40 mg retatrutide pen, graduated at 15 clicks per 2 mg, which gives 20 increments of 2 mg from a full cartridge. For a laboratory working through repeat measurements that means fewer cartridges handled for the same total mass. Dial graduation varies between suppliers, so check the stated clicks per mg rather than assuming it carries across from one format to another.

Retatrutide pen price in the UK

A 40 mg retatrutide pen is £160. UK delivery is free on every order, tracked as standard.

Bulk pricing applies automatically in the basket: two units take 8% off, three or more take 14%. For volumes beyond ten units, our wholesale page covers trade tiers and invoice payment.

Where to buy retatrutide pens in the UK

You can buy a reta pen from us directly. We hold UK stock and dispatch the same working day on orders placed before 2pm, cold-packed in thermal-insulated, tamper-evident packaging. Delivery is tracked. Reta pen UK stock is held in our own facility rather than drop-shipped, so the reta pens for sale on this page are the ones we dispatch. Researchers looking for where to buy reta pens in the UK will find one format only: the 40 mg pre-mixed pen described above.

Payment is by open banking or direct bank transfer, authorised in your own banking app. Supply is to laboratories and research professionals only.

Retatrutide in the UK: stock, format and dispatch

We hold retatrutide in the UK rather than bringing it in against each order, so a domestic order carries no import wait and no customs step. Stock is held refrigerated and goes out cold-packed the same working day when the order is placed before 2pm.

Retatrutide is supplied here in one format only: the 40 mg pre-mixed pen described above. We do not supply lyophilised vials, and we do not supply to individuals. Orders are accepted from laboratories and research professionals, for laboratory research use only.

A fuller account of retatrutide’s UK regulatory status, how pre-mixed pens compare with lyophilised vials, and how dial graduation works is set out on our retatrutide in the UK reference page.