Color Filler for Hair

Long hair with a beautiful color
Photo: Hugo Felix/Shutterstock
Q: Does color filler really help to make your hair color stay longer? How does it work?
A: Color fillers are typically tinted protein enrichment formulas that are designed to add substance to hair that might be damaged and weakened by color or other chemical processing.
The tinted protein bonds with the internal structure of the hair, making it stronger and giving the color a boost that is harder to wash out because the protein bonds to the hair.
You can also find neutral protein fillers that have no color of their own, but which bond with hair that may have been damaged by prior services and give the hair additional internal structure with which the color applied may bond to ensure richer, deeper color that lasts longer.
The problem many people face with repetitive color services, especially those that are high-lift or two-process color services (where the hair is bleached then toned) is that the hair can lose some of its substance in the process of having the base color "dispersed".
See also:
How to color hair
Questions about damaged and weakened hair
How to make hair color last longer
Will no ammonia hair color fade faster than hair dye with ammonia?