Our RETATRUTIDE 64 pen holds 64 mg of retatrutide in 3 ml, pre-loaded: the same compound as our 32 mg pen, at twice the concentration, in the same fill volume. That is the whole difference, and this page says so plainly rather than let the larger number imply a better product, then covers what arrives, how to read the pen against its certificate, and where the clinical programme stands.
What a double-concentration cartridge is
Both of our retatrutide pens use the same 3 ml cartridge. The RETATRUTIDE 32 holds 32 mg, which works out at about 10.7 mg/ml; the 64 holds 64 mg in the same 3 ml, about 21.3 mg/ml. The peptide is already in solution in both, so nothing is reconstituted and there is no vial to draw from; the two formats are compared at pen vs vial.
A multi-dose pen meters by volume. The dial selects how much liquid leaves the cartridge, and the pen has no way of knowing what that liquid contains (how a peptide pen works). The same setting on either pen therefore draws the same volume, and from the 64 that volume carries double the retatrutide. That is the one safety-relevant fact on this page: the two pens are not interchangeable, and a setting used with one does not carry across to the other. It is a fill fact rather than a dose, and we publish no schedule for either strength.
What it is not
A higher number on the label is a quantity, not a grade. The 64 mg pen is not a different compound, not a purer one and not a more advanced one. Retatrutide is the same molecule acting on the same three receptors at either concentration, and concentration in the cartridge does not change how the molecule behaves in the body.
It is not a dose, either: a cartridge’s total content says nothing about how much anyone should use. And it adds nothing to the evidence, which describes the compound as its sponsor supplied it to the trials, not any pen of ours at any concentration.
| RETATRUTIDE 32 | RETATRUTIDE 64 |
|---|
| Total retatrutide | 32 mg | 64 mg |
| Fill volume | 3 ml | 3 ml |
| Concentration | about 10.7 mg/ml | about 21.3 mg/ml |
| Retatrutide in any given volume drawn | 1× | 2× |
| Compound, receptors, evidence, regulatory status | identical | identical |
Who the 64 is for
Nobody needs the 64 in order to use retatrutide; the 32 is the same compound. The 64 is listed for someone who is already using retatrutide, has settled on the 32 mg pen, and wants fewer cartridge changes and fewer cold-chain parcels for the same total quantity. That is a logistics preference, and the only reason to choose one strength over the other.
If you have not used retatrutide before, the compound gives no reason to prefer the larger fill, and an opened pen cannot be returned. A pen left part-used for a long stretch also argues for the smaller fill: once a cartridge is open, its in-use life rather than the printed expiry is the number that matters (shelf life and expiry dating).
Both strengths are listed under the weight-loss goal. The Advanced Lean Stack pairs the 32 mg pen with NAD+; the 64 is sold on its own. If you would rather have the dual agonist with an authorised medicine behind it, that is tirzepatide, in our TIRZEPATIDE 60 pen; the two compounds are set side by side at retatrutide vs tirzepatide.
What arrives, and what to check against the label
Inside the discreet outer packaging you find the pen, eight standard threaded pen needles, a printed guide, a verification sticker, an insulated box with a cooling element, and a temperature indicator. No certificate is printed. Scan the QR code on the pen, or open the index at /coa, and the PDF for your batch opens as a plain file with no account.
Two strengths in an identical cartridge means the arrival check has one extra step. First the temperature indicator: a breach, damage or a pen that does not work is replaced free of charge once you send us photos or a short video. Then the seal. Then the label: read the batch number and the strength printed on it, 64 mg, against the certificate the QR code opens, which states the concentration in mg/ml and the total mg in the 3 ml fill. The two strengths are separate production runs, so a certificate for one says nothing about the other, and a label that says 64 should open a certificate that says 64. How lot numbers are matched is set out at batch and lot matching; if yours does not match, contact us before using the pen.
Testing and the certificate
An independent laboratory tests every batch: identity by mass spectrometry, purity by HPLC, and sterility. The certificate for a 64 mg lot shows the laboratory’s purity figure and the concentration it measured, as mg/ml and as total mg in the cartridge, which is the line that confirms the double-concentration pen you ordered is the one you received. The document belongs to that lot alone, not to a representative sample, and the QR code and the index open the same PDF. We do not name the laboratory; the purity figure is the laboratory’s, not ours.
The evidence, at programme level
Retatrutide activates the GIP, GLP-1 and glucagon receptors; tirzepatide covers the first two and semaglutide the second alone. The class is laid out at incretin peptides and the molecule itself at what is retatrutide?. The evidence belongs to the compound, not to either pen, so we keep it short here; the full account is on the 32 page.
One Phase 2 trial is in print: 338 adults, 48 weeks, double-blind and placebo-controlled, in which the 12 mg group’s mean weight change at 48 weeks was −24.2% 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). Gastrointestinal adverse events were the most common and were dose-related. The Phase 3 obesity programme, TRIUMPH, has its design published (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). Its lead trial, TRIUMPH-1 (NCT05929066), enrolled 2,335 participants and is listed on the registry as completed on 30 April 2026, with no results posted at the time of our review. The first Phase 3 result in print is in type 2 diabetes rather than obesity: TRANSCEND-T2D-1, a 40-week trial in 537 people, in which every retatrutide dose lowered glycated haemoglobin more than placebo (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).
At either strength, retatrutide holds no marketing authorisation from the EMA or from any EU national authority. Its status is investigational, meaning in active development and neither approved nor abandoned, and a larger cartridge is not a step toward approval. How that position applies across our range is at why these compounds are not EMA-authorised.
Delivery and returns
Order before 12:00 on a business day and the pen leaves our Czech dispatch point that day; delivery across the EU takes 3–5 business days, tracked door to door, with the link by email and by WhatsApp if you opt in. Dispatch is inside the EU, so there are no customs charges and no import paperwork. From dispatch to your refrigerator the pen stays at 2–8 °C in the insulated box with its cooling element and indicator (cold-chain shipping).
If a pen is unopened, unused and still in its original sealed packaging, you can return it within 30 days of delivery; we refund in full to the original payment method within 5 business days of approving the return. Opened or used pens cannot be returned. Breach, damage or a pen that does not work is a replacement rather than a return, as above; the full terms are at returns. Buying requires an account and our eligibility quiz, and we sell only to adults aged 18 and over.
