that's a low dose cycle 
~100mg a week is about trt, although blood values should guide dosages
People can put on muscle when TRT+ dosages are used (200+, etc). Just as they can w/ pro-hormones and other things.
And they up their calories. And maybe they haven't maxed out natural growth yet. Maybe not life-long/seasoned trainers.
I can say, that after training from 1978-2016 natty (38 years) very seriously and going on real TRT dose (100-125 mg) I gained zero muscle or size.
Im still in "normal/high" range (just did bloods last week) and it just helps to feel better w/ age. And maybe help with staying in shape for those who try to.
It is not magic like some may think...
(When in your 20's, and maybe had these test-levels, you didnt grow like a juiced-BB, sorry)...