I was always told that you can use a 25 gauge needle to inject test eth and fina. Well who ever is looking to do these two drugs should not use a needle this small. The liquid will not pass through a needle with a gauge that is this small. Even if you do get the liquid through it would take you all day long to inject it into your body.It just wont happen. I even think your pushing it with a 23 gauge needle. Personally i use a 22. The reason why i am writting this is because i purchased a ton of 25 gauge needls before my cycle to then fina out they were useless. The moral of the story is if you want to used either of these two drug dont get a 25 gauge needle.