The Right Needle
21 Gauge needle used to inject steroids into deep muscle tissue. Many people ask me what needle to use to inject steroids and the answer is simple. 21 gauge (which refers to the thickness of the needle. The lower the number, the thicker it is. One-and-a-half inch length is approximately 38mm.
The reason for using this exact size is not so obvious. There are two types of steroids, oil-based (very seldom a thin oil) and water based suspensions. The thick oil based steroids need a thicker needle to suck up the oil into the syringe and to be able to inject it smoothly. This is critical because 99% of all people injection oil-based steroid with a needle that is too thin. It is likely going to end up in a painful injection site for days.
Why use the right needle?
The reason for this is two-fold. The excessive force needed to inject the oil through a thin needle. This means there is a lot of movement of the needle when injecting and this bruises and damages surrounding tissue. The second issue is that the force with which the oil leaves the needle tip causes further damage to the tissue. Imagine forcing water down a very narrow hose pipe, it will spry out harder and further than out of a big hosepipe.
With water bases suspension, thicker needles are also essential. Because these are suspensions, meaning particles are not dissolved in the water but floats in it so to speak, the risk of these particles clogging the needle is very high. Anybody that has injected Aqua Test, for instance, will tell you how often it clogs the needle.
This leads to the conclusion that you need a thicker and longer needle to inject deep in the muscle without excessive force. The 23 gauge long needle is the way to go.