Let's say I have a tune and its peak volume is -0.5dB. If I normalize it down to, say, -3dB, and then back up to -0.5dB later, there's no loss of any kind, correct? (assuming I'm working on a raw WAV). Of course if I normalize to something really low like -30dB, and then raise it back up, I might've lost some softer parts of the piece. But I'm talking just a matter of 6-10dB or so.
You might wonder why I don't already know the answer to something this simple. I used to know, but aliens stole it from my brain.