From my understanding, if you are looking for optimal muscle growth, night is better. Not just because testosterone is up, but also because your body shifts to an anabolic state somewhere in the late afternoon and so your post-workout meals will be more efficiently transported to muscle growth.
In contrast, morning lifting might be better as part of a combined weights + cardio routine if you are looking to lose fat. In the morning, your body has released fatty acids into the bloodstream, and it is in a catabolic state, which means it is more primed to break down fat for fuel.
In contrast, morning lifting might be better as part of a combined weights + cardio routine if you are looking to lose fat. In the morning, your body has released fatty acids into the bloodstream, and it is in a catabolic state, which means it is more primed to break down fat for fuel.