I'm 28 and got back on trt this may which is roughly half a year now. Blew up initially as soon as I got back on then torn my rotator cuff, then fasted for a month with ramadan, but rotator cuff still screwed (drastic jump in strength too fast) so I can't train as intensely for some time now and lost those gains, but still feeling great! I was off prior to may for 10 months and prior to those 10 months on trt for one year. Reason I got off was for fertility.
TRT was a game changer for me. Prior to the first trt I had one year of struggling, turned terribly weak and skinny fat. Absolutely terrible as prior to that I never had issues, super strong raging libido, athletic, into sports, etc... then out of no where no matter how i train no matter how i eat, total shit results and no libido/depression.
The 1 year of trt totally changed me and was awesome, within one year went from 196lbs to 194lbs but TOTAL body composition change veiny and lean, my body felt rock solid. Literally doubled and in some cases trippled my strength in exercises. It was SO bad I was before trt struggling with 180lbs deadlifts... HORRIBLE then went to doing 405lbs, not that impressive compared to some but within one year the changes were quite few and drastic for me. The best size wise was for me 36-37" waist and 230lbs, this was 194lbs with 33" waist but real solid and veiny, looked better. My goal ideally is 210-230lbs solid/ripped.
Unfortunately when I got off within only two weeks, gained 3" on waist, lost all muscle (had visible broad lats and very broad shoulders) all just went poof... and then that followed 3 months of straight depression. Was on clomid/daa/ai/etc... to set myself to somewhat manageable state. After 10 months produced enough sperm to freeze a bunch and now back on.
So far lost 5" off waist in last 6 months gained some mass and strength, but no where near where I was last year, but hey it takes time and I have to take it easy with the rotator cuff. Never planning to get off ever again as feeling awesome is awesome
I had a rollercoaster of fat gain/fat loss and muscle gain/muscle loss in past 3 years.
I recommend those that need it to try to do everything possible to have kids, freeze as much sperm, it's worth it, and then consider trt for sure.