"Clean Spirit" is a great documentary on the Argos Shimano team the the 2013 TDF, the first year he dominated the sprints. It is one of the numerous cycling movies on Netflix (also watch Pantani, Rising from the Ashes, Stop at Nothing, and Slaying the Badger). There are many interesting moments, but I just want to focus on the supplements scene.
First of all, I was surprised that their physician would share what supplements their racers were taking. I would have thought it'd be more secretive. Here's the list of what he said all their racers take (and they all take the same):
Caffeine Pills (if they have a chance of winning)
I've taken the usual supplements, a multi-vitamin daily, and protein powder post workouts. On days that I'm doing more strenuous training, especially in the heat, I may take an iron and a magnesium pill as well. I figure that with all the sweat and exertion, my body is losing more minerals that usual and that they need to be replaced. I also try and eat salty foods like cocktail peanuts or food from restaurants (always salty!) to replace the salt.
Does it help? It does to me. It certainly hasn't made me any faster or anything like that, just less rundown overall. I know that could just be placebo, but my legs feel more rested day after day. Still sore, but just not quite as sluggish.
I think it's far less important than eating habits, but it's an easy way to try and (maybe?) keep your body in good shape.