No difference in dosing or profile. It's the same form of T - oil suspension (cypionate or enanthate). You're just asking for a smaller needle. Many states allow over the counter purchase of needles anyway.
You might hear from them that oil suspended T won't go through a 25, 26, 0r 27 gauge needle, but that simply isn't true. It can be tricky cuz many of the small gauge (insulin size) needles aren't removable from the barrel. So you have to either draw and shoot with the same needle, or use a different fill method. But tat depends on the brand of syringe & needle. (Ordinarily, for IM, you should draw with a larger gauge needle, like an 18-21, and replace it and shoot with a smaller gauge and fresh/unblunted needle. Less pain, less damage to muscle, and faster, with fewer annoying little bubbles.)
If your dr is hesitant to prescribe the smaller needles for subcutaneous injection, I know that Fenway Health's staff in Boston heard about it from Dr Norm Spack (Children's Hosp, Boston - expert in child and teen trans care & hormones - google him, interesting guy). It's increasingly common, even though it's not the standard administration method for oil suspensions. But it works - same uptake of hormones, same blood levels - data from non trans guys (hypogonadal) as well as trans guys.
Only difference, apart from less pain and anxiety, and a different location, is that some guys find it easier to do weekly shots of a smaller volume.
