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Retatrutide 40 mg · multi-dose pen
The concentration is fixed at the factory.
Each pen holds 40 mg of retatrutide in 3 mL of solution (13.33 mg/mL), ready to use with no mixing steps. Every batch has its own certificate of analysis.
- In-house productionThe process runs from filling to the box inside a single plant.
- Controlled environmentCritical stages take place in clean rooms with filtered air.
- Cold storageThe pen is kept refrigerated, between 2 and 8 °C.
- Laboratory analysisThe results for each batch are recorded in its certificate of analysis.
VLS technical team beside the filling line · Illustrative images of the production stages.The factory
A brand that can show how it produces.
Manufacturing is not the same as putting a label on something. It takes clean rooms, calibrated equipment, trained staff and records that can be reviewed at any time. That structure lets us answer for each pen: which batch it was filled in and which tests it passed.
- Written procedures and a record of every stage
- Environment and equipment under control
- Batch, expiry date and code on every box
From ampoule to box
Six stages, one standard
The journey of a pen through the plant, in the order it happens.
01Clean room and controlled environment
Critical stages take place in clean rooms, with filtered air and environmental conditions that are controlled and recorded. Staff enter in dedicated clothing and follow written procedures.
02Filling ampoules and cartridges
An automated line fills each ampoule with the same volume of solution. That way every unit holds 40 mg in 3 mL, without the variation of manual filling.
03Sealing the ampoules
As soon as filling ends, each ampoule is sealed hermetically to protect its contents. The seal is inspected before the next stage.
04Pen assembly
The sealed ampoule is fitted into the body of the multi-dose pen, with its window and selector. Every assembled unit is checked before it goes to packaging.
05Packaging, batch and code
The pen is placed in its box together with 4 needles of 3.0 mm. The packaging receives a batch number, an expiry date, a verification code and a security seal.
06Laboratory quality control
Samples from each batch are analysed to confirm identity, purity and content, and the results are recorded in the certificate of analysis.
See each stage in detail Illustrative images of the production stages.
Available now
Retatrutide 40 mg in a multi-dose pen
A solution prepared at the factory, in a prefilled pen. There is no powder to dissolve and no reconstitution calculations to make. The box holds the pen with 4 needles of 3.0 mm.
- 13.33 mg/mLThe same concentration in every unit.
- Dose windowThe selected setting can be read in the pen’s window.
- 3 mm needlesFour included, for subcutaneous use.
- Batch and codeSeal and verification code on the packaging.
The moleculeRead about the molecule
A peptide that binds three receptors
Retatrutide was designed to switch on the receptors for GLP‑1, GIP and glucagon at the same time, three signals the body uses to coordinate appetite, glucose and energy expenditure. It is being studied in phase 3 clinical trials, and the published results describe group averages, never what will happen in any one person.
GLP‑1Takes part in the satiety signal and in glucose-dependent insulin release.
GIPActs on glucose and lipid metabolism and complements GLP‑1.
GlucagonIs linked to energy expenditure and to the use of fats.
Peptides in brief
From sequence to effect
A peptide is a short chain of amino acids. The order of that chain decides which receptor it recognises and which message it triggers.
01
The chain
Amino acids linked in a precise order. Change just one and you have a different molecule.
02
The receptor
Each sequence fits specific receptors on the cell surface, like a key in its lock.
03
The signal
Once the receptor is activated, the cell receives an instruction that plays a part in appetite, glucose or energy expenditure.
Research briefing
Open the briefing (in Spanish)The full research briefing
The science behind retatrutide and the multi-dose pen, explained in detail in a separate briefing. Opens in a new tab.
Vial or pen
Fewer steps between the box and the setting
Lyophilised powder calls for reconstituting, calculating and loading a syringe. The prefilled pen moves those steps into the factory.
Powder vial
- Powder and diluent are mixed before first use
- The final concentration depends on the preparation
- The amount is drawn with a syringe on a small scale
- Requires more manual steps before each use
- Separate supplies: syringes, needles and diluent
VLS pen
- Solution prepared and filled at the factory
- 13.33 mg/mL in every unit
- The setting is selected and read in the window
- 3 mm needles included in the box
- Batch and verification code on the packaging
Certificates of analysis
What the laboratory measured, in plain sight
Certificates of analysis (COA) show what was measured in each batch: purity, molecular mass, pH, peptide content, microbial limits and endotoxins. In retatrutide batch R20260318, the reported purity was 99.38%.
View certificatesCOA · active ingredientBatch R20260318
Purity99.38%
Retatrutide · produced 18 Mar 2026
Blog
All articles Reading to understand more
Articles on peptides, the pen, cold storage, how to read certificates and what has been published about retatrutide.
What is a peptide: from the amino acid sequence to the receptor
A peptide is a short chain of amino acids whose sequence decides which receptor it binds to. See how it forms, how it differs from a protein, and why synthesis and purity matter.
Read article
Powder vial or ready-to-use pen: what changes in practice
A short, descriptive contrast between a solution that arrives ready and a powder prepared before use: who does the preparation, how the amount is read, the batch and storage.
Read article
Batch, seal and serial number: what each code on the box shows and how to check it
What a batch code and a serial number each identify, how to check the seal and the code on the verification page or by WhatsApp, and what to keep as a record of the box.
Read articleFrequently asked questions
What people ask us most
What does it mean that the pen leaves the factory ready to use?
The solution is prepared, filled into an ampoule and fitted into the body of the pen inside the plant. Whoever receives it mixes and dissolves nothing: they fit a new needle and select the setting in the window.
How do I know which batch my pen is from?
The batch number is printed on the box, alongside the expiry date and the verification code. That number lets you locate the matching certificate of analysis.
What sets retatrutide apart from other peptides of its kind?
The first analogues acted on a single receptor, GLP‑1. Then came those that add GIP. Retatrutide adds the glucagon receptor: three targets in one molecule. Published studies examine that combination in groups of participants.
How does a pen differ from a powder vial?
A lyophilised vial is reconstituted before use, and the final concentration depends on how it is prepared. The pen arrives with the solution ready and the concentration set at the factory, so the manual steps and the way the amount is read are different.
What does 13.33 mg/mL mean?
It is the concentration: how many milligrams of retatrutide there are in each millilitre of solution. It comes from dividing 40 mg by 3 mL. The pen’s window already shows the selected setting, so you do not need to do that conversion in order to use it.
Got the box in your hand?
Check the code on the packaging at the manufacturer’s official page, or send us the batch number on WhatsApp.