You cannot use regular shampoo to wash out a relaxer, as it weakens the hair and causes it to swell. Regular shampoo does not contain the necessary neutralizing solution needed in order to neutralize the chemical process and protect the hair from over processing.
Regular shampoo strips the hair of its natural shine and makes it vulnerable to dryness, and brittleness. Only a neutralizing shampoo can counteract the chemicals present in a relaxer and lower the pH balance of the hair. Regular shampoo can cause damages the cuticles, leaving them open to absorb water and causing the hairs to swell. Neutralizing shampoo is often included in the relaxer kit. If it is not included, it is available for purchase at various salons and stores.