There is serum test and then intermuscular test, if I'm not wrong? When you workout, what is already in your muscles is what's going to affect your growth, not what is going through your bloodstream at that particular time. I know its different with carbs and protein than with test but that is what I've read so go figure.
Since we're talking about it...for me.....I myself have suffered from insomnia all my life. I have to take meds to go to sleep, and even then sometimes my mind will find a way to stay awake, no matter what.
Its like if I workout in the morning then I can get it overwith, have my "breakfast" in the form of protein/carb shakes and multivitamins, and then all day I can "come down" from the workout. What is "difficult" for others during the day is not only easy for me, its coming down from my workout. Its really great!
By evening time I'm ready to really relax as my body just sinks into a really "feel good" state that it normally wouldn't if I didn't workout. I sleep much better this way. However.....
My joints don't like morning workouts, especially my knees with squatting. I guess I'm going to have to try longer warmups. This seems counterproductive, though, because my joints and my body in general is very primed to workout in the evening (though I'm really tired after work). Which brings me to another benefit of morning workouts, I'm not too tired to do it for that day and it doesn't ruin everything by missing a scheduled workout.
So you can't just weigh only one factor. You have to weigh ALL the factors and do what's best for you.