Retatrutide (research code LY3437943, often shortened to ‘reta’) is a synthetic peptide under development by Eli Lilly. In the scientific literature it is described as an agonist at three receptors: those for GIP, GLP-1 and glucagon. Retatrutide has no marketing authorisation in the EU or the US and is still being studied in clinical trials. Clean Peptides supplies retatrutide exclusively as reference material for laboratory research, as a pre-filled pen and as a vial of lyophilised powder, each in 15, 20, 30 and 40 mg.
For research purposes only. Not intended for human use.
All retatrutide variants
Prices and stock levels below come straight from our shop, so they are always up to date.
Retatrutide pens: 15, 20, 30 and 40 mg
Retatrutide vials: 15, 20, 30 and 40 mg
Go directly to a product: Retatrutide pen 15 mg · Retatrutide pen 20 mg · Retatrutide pen 30 mg · Retatrutide pen 40 mg · Retatrutide 15 mg (vial) · Retatrutide 20 mg (vial) · Retatrutide 30 mg (vial) · Retatrutide 40 mg (vial). You can browse the full range in the shop, and the retatrutide pens and vials are also listed in the relevant product category.
Pen or vial: the differences
| Feature | Pre-filled pen | Vial |
|---|---|---|
| Form | Retatrutide in solution, in a pre-filled pen | Lyophilised (freeze-dried) powder in a glass vial |
| Strengths | 15, 20, 30 and 40 mg | 15, 20, 30 and 40 mg |
| Reconstitution required | No, the substance is already in solution | Yes, the powder must first be dissolved in the lab; the solvent is sold separately |
| Storage | Refrigerated (2–8 °C), dry and protected from light | Unopened: refrigerated (2–8 °C), dry and protected from light |
Both forms contain the same substance. They differ in the form in which retatrutide is supplied and in how it is stored. We do not provide any guidance on use in humans or animals.
About retatrutide: substance and status
Retatrutide was developed by Eli Lilly under the research code LY3437943. It is a triple agonist: the literature describes it as an agonist at the receptors for GIP (glucose-dependent insulinotropic polypeptide), GLP-1 (glucagon-like peptide-1) and glucagon [1]. Its CAS number is 2381089-83-2.
Retatrutide is not an approved medicine. It has no marketing authorisation in the European Union (EMA) or the United States (FDA); so far, the substance has only been studied in clinical trials.
State of research
In 2022, Eli Lilly researchers published a description of retatrutide covering everything from its discovery to the first clinical study in humans [1]. Two phase 2 studies followed in 2023: one with 338 participants over 48 weeks (Jastreboff et al., NEJM 2023) [2] and one with 281 participants over 36 weeks (Rosenstock et al., The Lancet 2023) [3]. The phase 3 TRIUMPH programme, which covers several study populations, is still under way [4][5]. Until phase 3 has been completed and assessed, retatrutide remains an investigational substance. We make no claims about effects or outcomes.
Sources
- Coskun T, et al. Cell Metabolism 2022;34(9):1234–1247. Discovery and first clinical study of LY3437943. ScienceDirect
- Jastreboff AM, et al. New England Journal of Medicine 2023;389:514–526. Phase 2 study (NCT04881760). doi:10.1056/NEJMoa2301972
- Rosenstock J, et al. The Lancet 2023;402:529–544. Phase 2 study (NCT04867785). doi:10.1016/S0140-6736(23)01053-X
- Giblin K, et al. Diabetes, Obesity and Metabolism 2026;28(1):83–93. Design of the phase 3 TRIUMPH studies. doi:10.1111/dom.70209
- Eli Lilly Medical Information. Overview of ongoing clinical studies with retatrutide (updated 11 February 2026). medical.lilly.com
Quality and delivery
- Purity: every batch is tested by HPLC to confirm a purity of ≥ 99%.
- Batch number: every batch has its own batch number, printed on the label of every pen and vial. If you have a question about quality, we use your order number to look up which batch you received.
- Shipped from the Netherlands: all orders are dispatched from the Netherlands with tracking.
- Delivery time: based on our measurements from February to September 2026, parcels within the Netherlands usually arrive 1 day after dispatch, and parcels to Belgium and Germany after 2 days (median). Delivery to other EU countries usually takes 3 to 6 days.
For laboratory research only
All Clean Peptides retatrutide products are intended exclusively for research purposes and not for human use. Retatrutide is not an approved medicine. We only sell to customers aged 18 or over, and we do not provide any information on use in humans or animals, not even via WhatsApp or email.
Frequently asked questions about retatrutide
What is the difference between a retatrutide pen and a vial?
A pre-filled pen already contains retatrutide in solution. A vial contains lyophilised powder that must first be dissolved in the lab; the solvent is sold separately. Both forms come in 15, 20, 30 and 40 mg. The table above sets out the differences.
How should retatrutide be stored?
Keep the pen and the unopened vial refrigerated (2–8 °C), dry and protected from light. The expiry date is printed on the label.
How quickly will my order be delivered?
We ship from the Netherlands with tracking. Based on our measurements from February to September 2026, parcels within the Netherlands usually arrive 1 day after dispatch, and parcels to Belgium and Germany after 2 days (median). Delivery to other EU countries usually takes 3 to 6 days.
How can I pay?
You can pay by iDEAL, Bancontact, credit card or bank transfer. If you pay by bank transfer, you receive a discount, which is shown at checkout. We do not offer Klarna or PayPal.
Is retatrutide legal?
Retatrutide is not an approved medicine: it has no marketing authorisation in the EU or the US and is still under clinical investigation. We sell retatrutide exclusively as reference material for laboratory research, not for human use. Rules on buying and importing it vary from country to country, so check what applies in your country before you order. We cannot give legal advice.
Does every product have a batch number?
Yes. Every batch has its own batch number, printed on the label, and is verified by HPLC. If you have a question about the quality of your product, email your order number to shop@cleanpeptides.eu and we will look up which batch you received.
Do you give advice on how to use retatrutide?
No. Our products are intended exclusively for laboratory and research use. We do not provide any information on use in humans or animals, not even via WhatsApp or email.
