I am new, Where do I start?
You are not alone, there are lots of people just starting out on their own personal research journey and interested in adding Research Pens to their protocol
There are many resources available online like videos, podcast, and blogs that explain reconstituting research compounds, loading research pens and techniques.
These research pens are used for many different purposes and there is an assumption that researchers have a basic institutional knowledge of intended use, how to disassemble, load cartridges, reassemble these devices. As a result we do not provide instructions with the orders.
With that said, we are happy to assist and answer detail questions. Please send a request to Info@pen-depot.com
Shipping Speed - All products ship from the US - Standard shipping is about 4 days. We also offer expedited shipping.
Most orders received by 2p Eastern US time ship same day.
Special Care When Loading Cartridge
Pen-Depot Research Pens ONLY use 3ml - 11ML Long Stopper cartridges.
The maximum compound capacity is exactly 3mL Please consider this in your research protocol.
When transferring compounds to the cartridges for use, it is necessary to vent the cartridge to prevent the rubber stopper from blowing out the bottom of the cartridge.
Here are some techniques to keep your compounds safe.
Our 2 Recommended Options are below
These are the preferred and most controlled way to transfer compound into a cartridge while maintaining a closed, sterile environment.
“Vent Air Displacement Method”
Prepare 3 to 5mL syringe with your compound:
Prepare a vent:
Use a 1 mL standard insulin syringe as an air vent.
Unwrap the syringe, remove all caps and needle guards, and pull the plunger completely out.
You’ll be left with an empty syringe barrel, which will act as a vent allowing air to escape during transfer.
Create the vent path:
Insert the open syringe barrel into the self-sealing top of the cartridge.
This will serve as the air outlet while filling.
Begin compound transfer:
Insert a 3 mL syringe containing your compound directly next to the vent and inject slowly.
As the compound enters the cartridge, the displaced air will escape smoothly through the vent barrel, preventing back-pressure or stopper movement.
Result:
This process maintains a closed system, minimizes pressure buildup, and protects the sterile interior of the cartridge — making it a safe and controlled transfer method for research and compounding use.
"The Pump Displacement Method"
Prepare a 3 to 5mL syringe with your compound:
Remove all air from the transfer syringe before beginning.
Connect to the cartridge: Insert the syringe containing your compound into the self-sealing end of the cartridge.
Create vacuum transfer: Gently pull the syringe plunger upward to draw a small amount of air from the cartridge. Then release the plunger — the compound will begin to self-transfer into the cartridge.
Repeat the process: With the syringe still attached, pull the plunger up again to draw in another small amount of cartridge air, then release it. Each cycle will continue to move the compound slowly into the cartridge while displacing air back into the syringe. Continue until complete: Repeat this gentle pull-and-release motion until all air is removed from the cartridge and all compound has transferred. Fine-tune if necessary: If the flow slows or stalls, use short, slow plunger pumps — transferring only a small amount at a time and fully releasing the plunger between pumps to allow air to backflow into the syringe.
⚠️ Caution:
Do not pump too quickly or with excessive pressure.
Rapid or forceful plunger movement can cause the cartridge stopper to dislodge or blow out of the bottom of the cartridge.
Not Recommended — “Purge the Cartridge First” Method
Some users follow what’s known as the “Purge the Cartridge First” method, though it is not recommended due to contamination risk.
How it’s done:
It involves pushing the stopper all the way to the top of the self-sealing end of the cartridge which will force out most or all of the air before loading the compound. Thi is sometimes done with less than sterile pencil eraser or some new fangled 3D printed cartridge holders with purge tubes it the middle specifically made for this purpose. Then when the compound is later transferred into the cartridge, the stopper naturally moves back toward the bottom as the cartridge fills.
The BIG downside:
By purging the cartridge in this way, you expose the sterile interior of the cartridge to open air, which can introduce particles, dust, or other contaminants reducing sterility and increasing the risk of contamination during compound transfer.
For this reason, Pen-Depot does not recommend this method.
What is the difference between V1 and V2 model.
V1 models have a solid pen which allows you to completely close off the pen creating a sealed environment for storage. They come in different styles which include 60 unit standard size and 80 Unit slimline models.
V2 model have the “Injecthru” feature with a hole and retractable ring on the pen cap end. This allows for sight free needle administration. For those researchers with needle apprehension, this unique feature will hide the needle during administration. They only come in 60 unit standard versions.
Let's Talk Pen Tips
All of our Research Pens use standard insulin pen tips but Pen Needles Are Not All Created Equal
Even though most pen-tip needles look similar and are labeled as “universal fit,” their internal design, flow geometry, and manufacturing precision can vary significantly.
These differences don’t change how they attach to the pen, but they dramatically affect how they perform once dosing begins — including how much pressure you feel, how evenly the dose moves, and whether fluid drips after injection.
Small changes in wall thickness, bevel shape, surface polish, or silicone coating can mean the difference between a smooth, controlled injection and one that feels stiff, inconsistent, or slow to clear.
Key Mechanical Factors
Gauge & Flow Capacity
Pen needles typically range from 29 G – 32 G. Lower gauge numbers have a wider internal bore and allow easier flow.
For thicker compounds, choose a thin-wall or extra-flow design for smoother dosing and better pressure equalization.
Length
Options range from 4 mm – 12.7 mm
Shorter needles improve comfort; longer needles may provide more consistent delivery through denser tissue and less bruising at the injection site.
Bevel & Coating
Multi-bevel, silicone-coated tips reduce friction, ease insertion, and minimize drag.
Thin-Wall Engineering
Thinner steel walls increase internal diameter without changing external gauge, improving flow and reducing the likelihood of post-injection drip.
Hub Precision & Anti-Coring
Precisely machined hubs prevent leakage and protect cartridge stoppers from damage or material shedding.
Pen-Needle Brand Comparison - this is just a few available so do your own research.
BD Ultra-Fine
• Features: PentaPoint™ five-bevel tip, EasyFlow™ channel, micro-bonded silicone lubrication.
• Why It Stands Out: Ultra-smooth dosing and exceptional post-injection control.
• Best For: Premium users seeking the lowest resistance and most consistent delivery.
NovoFine
• Features: SuperFlow™ thin-wall lumen, short 4–6 mm lengths, ultra-thin comfort profile.
• Why It Stands Out: Exceptional comfort with quick pressure equalization after injection.
• Best For: Low-viscosity compounds and routine dosing.
Unifine Pentips (Owen Mumford) hard to get without a perscription
• Features: Thin-wall construction, triple-sharpened silicone-coated tip, anti-coring base.
• Why It Stands Out: Balanced combination of comfort and precision.
• Best For: Research or peptide dosing requiring smooth plunger movement.
TRUEplus (Trividia Health)
• Features: Five-bevel tip, thin-wall flow design, universal-fit threading.
• Why It Stands Out: Strong value with dependable performance.
• Best For: General research and daily compound delivery.
VeriFine / VeriFine Plus
• Features: Thin-wall tubing, dual-silicone coating, laser-verified QC.
• Why It Stands Out: Excellent balance of flow, comfort, and affordability.
• Best For: Cost-conscious users wanting premium-like performance.
MedtFine
• Features: Triple-sharpened, silicone-coated tips; thin-wall design; universal fit.
• Why It Stands Out: Smooth, consistent flow at a lower price point.
• Best For: Everyday dependability and comfort.
EasyTouch
• Features: Tri-bevel lubricated tip, thin-wall tubing, ISO-certified manufacturing.
• Why It Stands Out: Consistent production quality and low back-pressure variation.
• Best For: Mid-range users needing reliable, comfortable dosing.
Most of these can be found online at Amazon and other online diabetes stores.
Pen Tips. Here are some quick links to get you started.
Pro Tips
If using the “injecthru” V2 model please consider 5mm or longer pen tips.
Why a Pen Can Feel Hard to Inject or Leak After Dosing
Why a Pen Can Feel Hard to Inject or Leak After Dosing - this is rarely a faulty pen issue. Here are some of the most common things to consider.
1. Incomplete Dissolution of the Compound
If a reconstituted compound contains even small undissolved particles, they can partially block the needle and increase back-pressure. That same resistance can cause small drips after the plunger returns to neutral.
Always swirl gently (never shake) and confirm the solution is completely clear before loading.
2. Viscosity (Thickness)
Some formulations — especially peptides or hormone-based compounds — are naturally thicker and flow more slowly through narrow channels. Allow refrigerated vials to reach room temperature before dosing to reduce resistance.
3. Cartridge Alignment and Prefilled Design Issues
Pen-Depot pens are designed for 3 mL cartridges with an 11 mm long stopper. Using off-spec or prefilled cartridges with different stopper geometry, wall thickness, or glass tolerances can lead to plunger misalignment, uneven pressure, or dosing drag.
Ensure all cartridges meet the required specifications before loading into the pen.
4. Air or Back-Pressure (Priming the Pen)
Air bubbles trapped inside the cartridge can expand during dosing and push fluid back through the needle once the plunger relaxes — appearing as a drip. To avoid this, always prime your pen before use:
Turn the dose knob to 2–3 small units (or the smallest measurable increment), hold the pen upright with the needle facing up, gently tap to move any air to the top, then press the plunger until a small drop appears at the tip.
This removes air pockets and stabilizes internal pressure for a smooth, accurate injection.
5. Needle Flow Restriction or Design Limitations
Not all pen-tip needles perform equally. Variations in wall thickness, bevel shape, or hub precision can dramatically change how easily fluid passes and how effectively pressure equalizes after dosing.
Quick Review:
If your pen ever feels stiff or drips slightly after dosing:
Inspect the compound— confirm it’s fully dissolved and air-free.
Verify cartridge compatibility— only use 3 mL / 11 mm stopper cartridges built to Pen-Depot specifications; prefilled or off-spec cartridges can cause plunger drag.
Evaluate the pen-tip needle- restrictive or low-grade needles can increase resistance and delay flow.
Replace the needle after each use - to maintain sharpness and prevent residue buildup.
Allow time for full dose delivery. - After pressing the plunger, keep the needle inserted for at least 10 seconds before withdrawing. This ensures the complete dose passes through the needle and settles into the tissue. Smaller-gauge needles and thicker solutions may require slightly longer hold times. Tissue composition also matters - fatty tissue absorbs more slowly than muscle.
Many users choose thinner needles for comfort without realizing that undersizing can delay delivery and increase post-injection drip.
By understanding these mechanics — and selecting a thin-wall, silicone-coated, multi-bevel pen-needle designed for smooth flow — you’ll experience consistent dosing, minimal resistance, and optimal pen performance.
Also make sure to read the section on "Let's Talk Pen Tip"