When thinking for having a perm it is best to have you hair tested as a perm can damage the hair these will tell you where your hair is strong enough to take it. The are different test that you can do so I will talk you through them all.

* Elasticity test
This test is done to determine the condition and the strength of the hair,
You start by removing a few hairs from the front of the head then you need to pull the hair between you fingers. If the hair is weak or fragile it will break.
Hair that has good elasticity should be able to stretch up to half its own length when the hair is wet and only a third of it length when the hair is dry.
If the hair appears weak or breaks this mean the hair can not be premed.

*Porosity test This test is done to check the cuticle for damage.
Cuticle is the protective layer of the hair and if this layer of hair is damaged it will sock up the perm lotion to quickly, if this is to happen it is necessary to even out the porosity this can be done with a per-perm lotion or a restructurant after you have done this you can use a weaker or a specially formulated perm lotion.

How to determine the hair porosity the best way is to gently slide your fingers down the length of the hair shaft this means root to end.
If the hair is healthy it will feel smooth, and if the hair is porous it will feel rough.

Porous hair can be caused from previous treatments such as tinting or highlighting of the hair.

* Incompatibility test
This test is to determine whether the hair has had any chemicals on it that will react with the perm lotion.
How to do this you will have to take a small cutting of hair from various sections of the head, once you have done that place the hair in a simple bleach (a mixture of hydrogen peroxide and ammonia)

If the hair is incompatible the chemicals on the hair will get hot and foam then it will disintegrate therefore you can not carry out the perm.