I had a client with level 4n wanting to go blonde. I used Malibu C Un-Do-Goo followed by Malibu C CPR under the dryer for about 40 minutes. I used Un-Do-Goo to shampoo her 3 times. It lightened her to about a level 6! Then I foiled her all over with bleach and then shampooed with Un-Do-Goo again and sealed with Malibu C Miracle Repair. Her hair was SO healthy and the highlights pulled perfect! No damage whatsoever and my client loved the feel of her hair and the outcome going from a level 4 to blonde. AWESOME PRODUCTS!