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Injection Pens & Devices

Pen reviews, tutorials, and troubleshooting

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40 Topics 330 Posts
March 2026 Contest
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  • What could make pens better??

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    R
    Thanks, will do. That cart only has 1-2 shots left. My two new gansulins, Semax, NAD+, and label printer all hit the porch today, so today is a good day. More research homework to do tonight.
  • Purchased (2) Xulin 3 Pens today from peptide critic..

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    RandyR
    Ive always been against having one pen and multiple cartridges. Ive seen people accidentally do reta instead of tesa etc. A couple v2 pens and a pack of carts from our store, and some 4mm needles from amazon would be all you need https://peptidecritic.com/store
  • V2 Help

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    F
    @MyB Ah! Gotcha, that makes sense, thank you!
  • Adding to collection

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    S
    Nice! I have a v4 coming this week- very excited to see how much better it is than my beginner one that works well, but doesn't seem as quality as these!
  • I buy my pens and cartridges here. Where do you find vent needles?

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    P
    I use these 30 gauge 1/2 inch luer lock needles as vent needles.
  • Clear bayonet top for gansulin pens

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    T
    The Alcohol trick worked a treat. I'm really happy with being able to rotate cartridges and queue up the plunger within a click/U. It's funny, the lady and I both have 4 pens now. How this "hobby" grows.
  • Where are you buying the needle tips for the Auto Injectors?

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    R
    @Randy Thanks!
  • pen needles

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    RandyR
    @SEOCoder spot on. I do 6mm for glp because i really want to get the "fat juice" in there but 4mm is plenty.
  • Oils too?

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    J
    Droplet 29g 12mm pen needles may be the go to without spending a ton of money for specialty needles of greater length and bigger bore size. [image: 1771984686390-screenshot_20260224-175706.png]
  • Combined Vials and loaded pen

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    R
    Today’s fun was reconning 10x10mg SS-31 vials and loading them into 2 carts. Overall clean run with very little waste. I did 2 lines of 1 into 1 … with 5 vials each to keep it moving. Lesson: Make sure your vent needle doesn’t end up under the fill line or you may get backflow up the vent. I flipping love the Gansulin pen and need to get more of them. I also tried the 32g 6mm pen needles and they are sweet! Charlie the research cat doesn’t even feel them. Is there anything special to do with a loaded cart you aren’t using yet? I just put it in the Gansulin pouch. Might throw it in a little baggy. (I purged the excess air.) [image: 1771609356921-att.uojhjkoy2qc-2mehxq6b88trqpm8xyrq_61qjyqia3c.jpeg]
  • Advice on Pen purchase & accessories - Excited to elevate my research

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    P
    @ResearchCat Much appreciated.
  • 1.5mL pen vial

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    RandyR
    They're slightly shorter and thinner. They wont fit in any of the pens we have. The pens that use them are harder to find and disposable.
  • v2 pen cap hole?

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    RandyR
    less than a month. We had the factory produce plenty
  • Using a pen for TRT

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    D
    @Randy Holding down the button worked perfect this morning, that was definitely my issue! I do put the pen in a baby wipe warmer on medium heat overnight which I think helps with the flow (29 gauge). But my primary reason for using the wipe warmer is it eliminated the subQ lumps I was getting when injecting cold.
  • Cartridge use

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    D
    Thats a good question for @randy … I think he swaps them but when i was doing 4 peptides like bpc, TB, KPV, Ghk in all different pens i would use the same needle and toss it when done. Got the blend now so not needed. However i never mixed the needle with my RETA
  • Pen Comparison

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    D
    @Steve Im pretty much of a pen connoisseur as well. I have bought all of Randys pens and some others. So in my personal view i love my V1, why? Because it has a clicking action that i like. The V2-V3 practically, you push and its goes so you need to be more of an intermediate user if your trying to go slow. The new auto Gausen pen, is were i keep my Reta, its pretty bad ass, but i dont think i would swap pen vials or have 10 auto pens either. Randy just got a new Gausen pen not automatic im going to test out.
  • Pen volume

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    B
    @Bubba, the pens go down to 1 unit; not sure why you would want half a unit. Just double the back water when you reconstitute and use 1 unit. I think Jeff covered this on YouTube https://www.youtube.com/watch?v=geNpx5sJH3k. Basically, if you use as little as 1 unit, the little drip at the end of the needle contains more peptide than if you were using 5 units. I normally reconsitiute things so i'm doing 10units....Unless it's GHK-CU or something that stings, then maybe 20 units.
  • Love using Pens for research

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    R
    @mrjoshua44 It’s funny, I have cut my drinking by 90% or more since going on tirzepatide. My wife moved from Ozempic to Tirz and she hasn’t seen any reduction in desire for booze at all. The variability in these effects fascinates me. Think of the money we’re saving! Well, I am spending all that money on peptides and peptide accessories, so maybe not saving that much.
  • Pen Storage

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    RandyR
    I have a 1.5 year old v1 thats lived in the fridge its entire life. Still as accurate as day one.
  • Calculating dose from peptide pens

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    B
    1 ml with 10mg (is it tested at 10mg or labeled 10mg, big difference) will give you 100 units = 10mg, so 10 units would be 1mg.