trying to research about testoterone for someone and... having some issues

[creatures@chitter.xyz]

trying to research about testoterone for someone and... having some issues

found that there are oral capsules that contain "testosterone undecanoate"
"testosterone undecanoate" is also in injections (which confuses me) that are taken every 10-14 days

person wants to try microdosing and we were talking about estradiol and they were very interested in our knowledge - us only later realizing that they are interested in testosterone and not estradiol

actually not sure whether they'd be fine with testosterone gel, but now wanna know if testosterone stickies (estrogen version: https://stickies.neocities.org/stickies ) are a thing/possibility
also where to source the powder because DO doesnt have it

pls boost