Should I swap needles when drawing and injecting Testosterone?

When drawing Testosterone Cypionate or Testoterone Enanthate a lot of patients ask me whether or not they should swap the large bore needle they draw with (21-23G) and switch it out with a smaller one (25G 1'') before injecting. These are what I've found to be the advantages to using a single 25G 1'' needle for both the draw and injection:


1. Less waste.
2. Time is saved. Let me expand on this... The time it takes to put on one needle, draw the injection, pull back on the plunger to draw out the liquid from the 21-23G needle and hub, cap the needle, take off needle, open another package put on the new needle, uncap then inject is much longer than just drawing and injecting with 1 needle. At room temperature a 25G 1'' needle will draw 1mL of oil every minute (30 seconds to draw 0.5mL), so the time saved using a larger gauge needle would be negated due to the time loss of swapping needles.
3. Sterility is assured as swapping needles exposes the critical points of the syringe and needle ports to open air.
4. The stopper's life is extended. Using a large bore draw needle causes a large hole in the rubber stopper every time it is punctured. When large holes are present this causes the vial to no longer be a closed system, which increases the possibility of germs being introducing into the vial.
5. Coring is prevented. By not using a large bore needle you also prevent coring the stopper, which is the breaking off of a cylindrical piece of rubber into the vial due to the cutting action of the needle puncturing the stopper. This occurs more often as the bore of the needle increases.
6. Cost savings. Less supplies = less money out the door.
7. No more losses from not properly sucking out the oil from the draw needle before discarding.
8. Simplicity prevents confusion with the end user. Less steps in the administration process makes it easier for patients to be compliant with their dosing.


For a subcutaneous (SQ) injection a 29G 1/2'' syringe is what I recommend and it takes less than 1 minute to draw 0.25 mL.

#1 is a good enough reason. The increase in regulation regarding testosterone cypionate makes preservation vital to ensure you can get all your injections from a 10ml bottle. If your not careful, you may only get 8 (1ml) injections from a 10ml bottle due to wastage. Some waste is not preventable, but most manufacturers and compounders overfill bottles to compensate. The additional waste comes from needle exchange and not paying attention to detail on the syringe as the cypionate is being drawn.

Using the same needle to draw and inject can only be comfortably done as you stated if using a 25g or smaller needle. Anything larger, even a 23g, will be noticeably duller. The image below has circulated for years and I am not sure if the needle presented was injected into tissue or a rubber stopper, but I would think both would be similar (if not the rubber more dulling). Some name brands who use thicker oil, such as cottonseed, may not push through a 25g.

Another way to mitigate waste is to use a 1ml tuberculin syringe (with 25g needle) especially when dosing less than 1ml. The 1ml syringe allows you to be more exact with your dose and I personally find it easier to use and inject than the 3ml syringe.


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I think the smaller gauge needles (25g and smaller) actually dull more than the larger needles after passing through the plunger. I really notice the dulling of my 27g needles that I use for B12 injections.

I lose about .01 ML (one mark on the 1 ML BD syringe) going from a 22g 1" to a 25g 1".