I'm a little over two months on T, one shot every two weeks, and already I've got some decent muscle growth. I'm not even working out because I'm trying to fix some injuries.

I mean I'm not jacked or anything, but I have a bit more mass and definition. I first noticed it in my thighs when I put on my boxers and then when I was looking down at my arms I realized my biceps were bigger and more defined. This is crazy. I should start exercising to see what I can achieve. I've always wanted to be muscular since I was little but I couldn't build the mass before.

For those on T, when did you start noticing your muscle growth changing?

Probably in the first month.  I don't really remember. 

I'm 5 months

I noticed it pretty much right away(after a few weeks maybe). I'm 3 months on T. I have been working out some but even if I don't work out I still notice growth in my muscles.

After like about a month I believe. I work out too, but nothing too strenous (push-ups, cardio, and weights 3X a week). I've only noticed in my upper arms, not much in my thighs.

Heh. I didn't notice it till it was fairly far along, so I can't usefully answer your question. I wasn't looking for it at all, and then all of a sudden, abdominal muscles. I thought there was something wrong with me. Some time later, I noticed biceps and thighs.

Wish I could lift weights. I would love to build up my upper body a little bit. Or quite a bit.

I've noticed it since I've started biking every day, I'm just over 7 months on T and have huge biceps I've done nothing except riding a bike to get and big rowing machine shoulders too. It's very cool. Just gotta wait another few weeks to start working out to make sure I'm all healed after top surgery.