Chlorine can react with about anything that contains ammonia or amines to form chloramine, so shampoos, lotions, shaving foams, or conditioners could also be responsible. Amino acids are named thus for their amine groups, so anything containing proteins or protein fragments will react. Amine oxides and triethanolamine are used as surfactants in cosmetics. Sweat is unlikely to be the culprit. Check the ingredients in your cosmetics.