I’ve written before about how I administer my estradiol in form of a fortnightly intramuscular injection. The chief benefit is that it offers the greatest degree of bioavailability; but at the cost of... you know, routinely poking myself.
I actually use two different needles. There is a large, 18g needle for drawing the medication from the vial (because you want a large needle when pulling liquid into the syringe); and a 23g needle for injecting (because the smaller the needle, the less discomfort it causes going in).
Thankfully, the needles are color-coded; and over time, I learned to recognize them. When I’m having blood drawn, it’s with an 18g (which is why the “You’ll feel a sharp pinch” speech has some merit to it). One time the technician used a 23g needle (maybe my vein was inaccessible that day; maybe it was from personal preference) - I barely felt it going in!
(I think next time I’m getting blood work done, I’m going to ask them to use a 23g...)
I’m fascinated by vaccinations, because they give the same “You’ll feel a poke” talk but honestly, there’s hardly an sensation at all compared to my routine injections. I looked up the spec sheet and discovered they are using 25g needles; and the last time I saw my endocrinologist I requested they proscribe me some to test with.
Anyway, this is a very long-winded way of saying that I got to try out a 25g needle today and honestly, it was such an improvement - there was no pain popping it in! I do have to be a bit more careful now as depressing the syringe plunger required a lot more effort (I assume estradiol cypionate is a bit more viscous than whatever medium vaccines sit in); and that has to still be done in a very controlled way.
All the same though: great experience; would recommend!