Perm solutions fall into four basic categories: exothermic, alkaline, acidic and gentle perms for damaged or colour-treated hair. The type of perm selected depends on several factors including hair type, texture and health. It also depends on the kind of curl desired. Stylists choose a solution type after a thorough consultation with the client.
Ideal for stubborn, coarse and hard-to-curl hair, exothermic perms possess an extra vial of solution that warms when it is poured into the main bottle of solution. Immediately after mixing, the solution starts producing heat. A plastic cap on the head traps in the heat and allows for quicker and more even processing of stubborn hair. Exothermic perms are reserved for stubborn, unprocessed hair (hair with no dyes, perms or bleach) and clients that are more than 75 per cent grey.
Alkaline perms, perms with a pH between 8.2 and 9.6 create strong curl without overly damaging the hair. Alkaline perms are perfect for fine hair that is stubborn to curl yet susceptible to damage. Alkaline perms penetrate the hair quickly, creating a strong curl that lasts longer than most other types of perms. Like most modern perms, alkaline perms do not require a heat source to process.
Acid-based perms, perms with a pH of 4.5 to 6.5, process hair more slowly than alkaline perms. They are intended for soft, easy-to-curl or damaged hair. The curl created with an acidic perm is softer and has fuller body. The curl created from an acid perm relaxes quickly and is more suitable for shorter hair that receives a lot of extra styling on a day-to-day basis. In the past, acidic perms were processed with heat. Today, they are processed at room temperature.
Damaged Hair Solution
Damaged or colour-treated hair requires a gentle, acid-based perm solution. Sometimes, though, even the most gentle perm is not enough to keep the damage at bay. Perm solutions intended for damaged and chemically-treated hair often contain an extra conditioner or protein treatment that strengthens the hair during the perm. Damaged hair perms also process the hair more quickly than other types of perms.