My wife has noticed this on myself 
I used to have more curly hair in my teens but lately it was a lot less curly, now my hair is perhaps more curly that in my teens . In my last blood test my free T was in the 40s, what does yours look like?
Anecdotaly, this seems to happen to other people too:
http://www.allthingsmale.com/community/threads/change-in-hair-texture-after-starting-trt.24328/
https://forums.steroid.com/hormone-replacement-therapy-low-testosterone-treatment-anti-aging/559593-can-trt-make-your-hair-curly.html
https://www.steroidology.com/forum/anabolic-steroid-forum/686592-curyly-hair-testosterone-levels.html
