The cooking process should bring the water to a full rolling boil for at least one minute before adding the food item (for example, making pasta). If the water will be at a slight boil for a long time, then this will also be protective. For example, you may be cooking beans or boiling chicken for 10 - 20 minutes.
While it varies based on the type of products used and the efficiency of the stylist, it usually takes around 1 1/2 to 2 hours to get hair colored at a salon, according to a poll by Glamour magazine....
She points to customers like Allor as proof that it works, and claims that within six to eight weeks customers can see their natural hair color coming in at the root (it doesn't change existing gray hair).