Our RETATRUTIDE 32 pen holds 32 mg of retatrutide in 3 ml, pre-loaded, with the certificate for its batch reachable from the QR code on the pen. Retatrutide is the compound in our range with the widest gap between how much it is discussed and how far its clinical programme has actually gone, so this page states both halves precisely: what arrives, what the trials examined, and where the record stands today.
What arrives
The parcel holds the pen, eight standard threaded pen needles, a printed guide, a verification sticker, and the cold-chain packaging: an insulated box, a cooling element and a temperature indicator, inside discreet outer packaging. The peptide is already in solution, so there is nothing to reconstitute and no vial to draw from; the differences between the two formats are set out at pen vs vial. The certificate of analysis is not printed. Scan the QR code on the pen, or open the certificate index, and the PDF for your batch opens without an account.
When the parcel arrives, look at the temperature indicator before anything else. If it shows a breach, or the pen is damaged or does not work, send us photos or a short video of the fault and we replace the pen free of charge.
32 or 64: one compound, two concentrations
We list retatrutide at two strengths, and the difference between them is quantity, not grade. RETATRUTIDE 64 holds 64 mg in the same 3 ml, so its solution is twice as concentrated. That has one practical consequence: a given setting on the dial draws the same volume from either pen, and from the 64 that volume carries twice the mass of retatrutide. The two pens are therefore not interchangeable, and anything worked out for one does not carry across to the other. This is a fill fact, not a dose; we do not publish a schedule for either strength.
| RETATRUTIDE 32 | RETATRUTIDE 64 |
|---|
| Total content | 32 mg | 64 mg |
| Fill volume | 3 ml | 3 ml |
| Concentration | reference | double |
| Mass drawn at a given dial setting | reference | twice the reference |
Each strength is made and tested as its own production run, so a certificate for a 32 mg batch says nothing about a 64 mg batch. The QR code on each pen resolves to its own lot.
What makes it a triple agonist
Retatrutide (development code LY3437943) activates three receptors: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon. Semaglutide acts on GLP-1 alone. Tirzepatide, the compound in our TIRZEPATIDE 60 pen, adds GIP and is a dual agonist. Retatrutide adds glucagon on top of both. Each addition is a different pathway rather than a stronger version of the last, and the glucagon receptor activity is the genuinely new element, the one thing that separates retatrutide from everything else in the incretin class. How the molecule was designed is on what is retatrutide?; the class as a whole, with tirzepatide and semaglutide beside it, is on incretin peptides.
What the Phase 2 trial examined
The trial behind most of the interest is a Phase 2 study published in the New England Journal of Medicine in 2023: double-blind, randomised and placebo-controlled, in adults with a body-mass index of 30 or higher, or 27 to under 30 with at least one weight-related condition. It enrolled 338 adults and ran for 48 weeks, comparing several retatrutide dose levels against placebo; the primary endpoint was percentage change in body weight at 24 weeks, with the 48-week change as a secondary endpoint. At 48 weeks, mean weight change was −24.2% at the 12 mg dose against −2.1% on placebo (Jastreboff AM, Kaplan LM, Frías JP et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med 2023. PMID 37366315). That figure drew attention because it exceeded what the dual and single agonists had reported at comparable points. The most common adverse events were gastrointestinal, dose-related, mostly mild to moderate, and partly reduced by a lower starting dose; a dose-dependent rise in heart rate peaked at 24 weeks and declined afterwards.
Two things a Phase 2 result does not do. It does not establish the compound as a medicine: Phase 2 finds a signal and selects doses, and Phase 3 is what regulators assess. And it does not describe any particular pen. The trial used material supplied by its sponsor; the paper says what retatrutide did in a defined group over 48 weeks, not what a pen contains. That is the certificate’s job.
Where the programme stands
The Phase 3 obesity programme, TRIUMPH, is registered and its design is in print: four Phase 3 trials in over 5,800 participants (Giblin K et al. Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials. Diabetes Obes Metab 2026. PMID 41090431). TRIUMPH-1, the lead obesity trial (NCT05929066), enrolled 2,335 participants and is listed on the registry as completed on 30 April 2026; at the time of our review, no results had been posted there or published in a journal. The one Phase 3 result in print is TRANSCEND-T2D-1, and it is a diabetes trial rather than an obesity trial: a 40-week trial in 537 people with type 2 diabetes, in which every retatrutide dose lowered glycated haemoglobin more than placebo and weight change reached −15.3% at 12 mg against −2.6% (Bajaj HS et al. Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial. Lancet 2026. PMID 42250575). A result in type 2 diabetes does not answer for the obesity programme, which has not reported.
Retatrutide holds no marketing authorisation from the EMA or any EU national authority. It is investigational, which is a real and specific status: in active development, neither approved nor abandoned. This is where it differs most from tirzepatide, for which an authorised medicine exists and a clinician can prescribe it; no authorised retatrutide medicine exists anywhere. How that position applies across our range is set out at why these compounds are not EMA-authorised.
Setting retatrutide’s Phase 2 percentage beside tirzepatide’s completed Phase 3 figures compares results at different stages of evidence maturity, and the comparison is fair only when the stage is stated next to the number. We do that at retatrutide vs tirzepatide and retatrutide vs semaglutide.
Testing and the certificate
Every batch is tested by an independent laboratory for identity by mass spectrometry, purity by HPLC and sterility. The certificate shows the purity figure by HPLC and the concentration of the cartridge, as mg/ml and as total mg in the 3 ml fill, so you can read the 32 mg on the label against what the laboratory measured. It is the certificate for that specific lot rather than a sample document, and it is the same PDF whether you reach it from the pen or from the index.
Delivery and returns
Orders placed before 12:00 on a business day leave our Czech dispatch point the same day. Delivery takes 3–5 business days across the EU, tracked door to door, with the tracking link sent by email and WhatsApp updates if you opt in. Because dispatch is inside the EU, there are no customs charges and no import paperwork. The pen travels at 2–8 °C from dispatch to your refrigerator, which is what the insulated box, the cooling element and the indicator are for (cold-chain shipping).
Unopened, unused pens in their original sealed packaging can be returned within 30 days of delivery for a full refund to the original payment method, processed within 5 business days of approval; opened or used pens cannot be returned. Damage, a pen that does not work, or a breached temperature indicator is handled as a replacement rather than a return, as described above. The full terms are at returns.
Where this pen sits in our range
You usually arrive here from the weight-loss goal, having read the Phase 2 paper and understood that it is a Phase 2 paper, and wanting the triple agonist specifically for its glucagon receptor activity rather than the compound with an authorised medicine behind it. If you want the higher concentration, the 64 mg pen is listed on its own. If you are pairing retatrutide with NAD+, the two pens are listed together as the Advanced Lean Stack. We sell to adults aged 18 and over, with an account and the eligibility quiz before checkout.
