Final answer:
Permanent hair color may leave the hair unsuitable for further chemical services.
Step-by-step explanation:
The color product that may leave the hair unsuitable for further chemical services is permanent hair color.
Permanent hair color chemically alters the hair's structure and removes the natural pigment. Once the hair has been permanently colored, it cannot be lightened or changed with another chemical process. If further chemical services are desired, such as lightening or recoloring the hair, it is best to use temporary, demi-permanent, or semi-permanent hair color instead.