Thinning hair poses a particular set of problems. It is easy to damage, and the desire to hold onto what is left is often very strong. Perms help thinning hair appear thicker, but they often result in breakage. Special care is needed to perm this type of hair.
Effects
Perms add curl and body to thinning, lifeless hair. The curl helps the hair appear thicker and aids in styling.
Resistance
Thinning hair is extremely resistant, meaning that it does not take or hold perms very well. A gentle perm solution is recommended, but it should be selected based on its strength as well.
Breakage
Hair that is thinning is not just getting sparser. Most of the time, it is also getting finer in diameter. Fine hair breaks easily.
Perm Rods
Large perm rods are used on thinning hair to reduce the likelihood of breakage. Large rods equal less tension and less breakage.
Perm Solution
alkaline perms are recommended for thinning, fine hair. The solution is strong enough to perm stubborn hair, yet it's safe.