Answer:
I am a protector. I sit on a bridge. One person can see right through me while others wonder what I hide.
Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.
Better touch me before you proceed to second.
My first is high my second damp my whole a tie a writer's cramp.
Find me on body builders or in the drink aisle.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.