The side-effects of chlorine come from a chemical reaction between chlorine and your hair and skin. Your hair is made of protein. Your skin is made of protein. Chlorine reacts with protein.
Before swimming, the best thing that you can do is saturate your hair and skin with fresh water. Also, wearing a swimming cap will keep your hair protected by preventing the chlorinated water from coming into contact with your hair.
In all honestly, nothing can keep you completely protected from chlorine. Swimming involves submerging yourself in pool water. Pool water is treated with chlorine to keep it healthy. The chlorine in that pool water will react with your hair and skin.
To prevent lasting damage, it becomes very important to wash chlorine off of you hair and skin after swimming. The only way to do this is to treat your chlorine-coated skin with a potent, concentrated antioxidant after swimming. The single best option for washing the chlorine off of your skin is by using a vitamin C spray.
Because it's chemistry. The pool chemicals react with your body chemicals. Then, vitamin C reverses that chemical reaction.... returning you back to normal. I figured this out because I am a chemist. Click the video below to get my story: