sunshinelady
New Member
Some people's hair is resistant to the chemicals used to open and close the scales of the cuticle. Often this is an inherited tendency. The only way to deal with it is to use stronger chemicals. Great care is needed with these, however, as they may damage the hair shaft so severely that it breaks.
Red hair is an example of this. The keratin of red hair tends to contain more sulphur than usual - it can be twice as much as the average -because it contains a high proportion of cysteine units. That means that there are many more disulphide linkages to be broken, and it is therefore more likely that a perm will fail to 'take' on red hair.
-Taken for Procter and Gamble, The World of Hair
Red hair is an example of this. The keratin of red hair tends to contain more sulphur than usual - it can be twice as much as the average -because it contains a high proportion of cysteine units. That means that there are many more disulphide linkages to be broken, and it is therefore more likely that a perm will fail to 'take' on red hair.
-Taken for Procter and Gamble, The World of Hair