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What is a color filler for hair?

A color filler for hair is a product that is used to even out the porosity and texture of the hair before applying hair color. It helps provide a more uniform result when coloring the hair by filling in gaps and holes in the cuticle. Using a filler allows the color to take more evenly across all strands, preventing issues like splotchiness or faded areas. Read on to learn more about how color fillers work and how to use them for best results.

What Does a Color Filler Do?

Hair is made up of a protein called keratin that is arranged in overlapping scales called the cuticle. The cuticle protects the inner structures of the hair strand. Over time and with damage from things like heat styling, chemicals, and environmental factors, the cuticle can become compromised. This leads to increased porosity and an uneven texture.

When hair is overly porous or damaged in some areas, it will absorb hair color differently than healthy areas. This can lead to an inconsistent end result. Using a filler evens out the porosity prior to coloring. The filler adheres to open cuticles and damaged areas, allowing them to absorb color more similarly to undamaged hair.

Benefits of Using a Color Filler

There are several benefits to using a color filler before applying permanent, demi-permanent, or deposit-only hair color:

  • More even color result
  • Longer lasting color
  • Prevents splotchiness and uneven tones
  • Improves gray coverage
  • Reduces the amount of dye needed for full coverage
  • Minimizes color fade

By filling in gaps in the cuticle, the color has less space to escape and oxidize. This keeps the shade vibrant for longer. Using a filler also decreases the amount of dye needed for complete saturation.

When to Use Hair Color Fillers

There are certain situations when using a filler is especially recommended:

  • Covering grays: Natural gray hair has a different texture and porosity than pigmented hair. Using a filler helps provide even absorption so grays blend seamlessly.
  • Coloring damaged hair: Hair that is very porous from chemical processing, heat styling, or environmental factors will soak up filler to prevent uneven dye absorption.
  • Changing color drastically: Switching from light to dark shades benefits from a filler to ensure even saturation and avoid splotchiness.
  • Cool toned hair dye: Ash and platinum shades show unevenness more than warm shades. Using a filler creates a blank canvas first.
  • Highlights/balayage: Fillers can be used just on highlight sections before applying lightener to prevent hot roots and enhance lifting.

Types of Hair Color Fillers

There are a few different types of color fillers to choose from:

Permanent Fillers

Permanent fillers use peroxide to swell the cuticle and deposit pigments that remain until they grow out with the hair or are cut off. They provide longer lasting filling effects. Brands like Redken offer permanent fillers.

Semi-permanent Fillers

Semi-permanent fillers coat the hair in pigments that eventually fade out over several weeks. They provide temporary filling before color with less commitment. Options like Olaplex No.4P are semi-permanent.

Protein Fillers

Protein fillers use hydrolyzed proteins to fill gaps in the cuticle and repair damage. They create a smoother cuticle surface without depositing pigment. Protein fillers like Aphogee 2 Step provide light filling effects.

Glossing Treatments

Some glossing treatments or colored conditioners can also provide filling properties by smoothing the cuticle. They provide subtle filling effects that fade out slowly with shampooing.

How to Apply a Hair Color Filler

Using a color filler is a simple process:

  1. Shampoo and towel dry the hair so it is damp but not dripping wet.
  2. Prepare the filler product according to the instructions.
  3. Section the hair and use a tint brush to apply the filler evenly from roots to ends.
  4. Leave the filler on for the recommended development time.
  5. Rinse thoroughly and towel blot dry.
  6. Proceed with color application as usual within 48 hours.

Choose whether to apply the filler to only the new growth if covering roots, only the previously lightened sections if coloring highlights, or all over if making a significant color change. Always follow up with shampooing a few days after coloring to remove filler residue.

Expert Tips for Using Hair Fillers

Here are some expert tips for getting the most out of your color filler:

  • Choose a filler shade closest to your target color for seamless results.
  • Apply filler on wet hair for even saturation into the cuticle.
  • Use a clarifying shampoo first to remove buildup and help filler absorb.
  • Don’t shampoo for 48-72 hours after applying filler for best retention.
  • Always do an allergy test by applying filler to the inner arm before using on hair.
  • Increase development time for very porous hair to allow thorough saturation.

Common Questions about Hair Fillers

Do you have to use a filler with box dye?

Using a filler is not required but can create better results when using box dye. It helps prevent splotchiness and uneven color results. Permanent fillers are best for maximizing box dye coverage.

Can you use semi-permanent dye as a filler?

Yes, deposit-only semi-permanent dyes can serve as a filler before permanent color. They provide subtle filling effects and add tone before coloring with permanent dye.

Should you use a filler with highlights?

It’s recommended to use filler just on regrowth and any previously lightened sections before touching up highlights. This prevents hot roots and splotchy lightening results.

When should you not use a filler?

Avoid filler if you have allergy or sensitivity to hair color. Only apply to healthy, intact hair and scalp. Fillers are also not necessary when doing an all-over color in your natural shade.

In Conclusion

Using a hair color filler is a great way to improve color results and create an even, consistent end look. Permanent fillers offer the most dramatic filling effects and longevity. But semi-permanent and protein fillers can also be used prior to hair color for smoother dye uptake. Fillers are especially useful when covering grays, lightening hair, or making a drastic color change. Follow the instructions carefully and always do a patch test before use.


The following references were used to provide information for this article:

  • Dove, J. (2021). How to Use Hair Color Fillers for Even Color Results. Byrdie.
  • Wright, V. (2021). Hair Colour Remover vs Filler—Which One Should You Use? Latest Hairstyles.,an%20even%20base%20for%20colouring.
  • What is a Hair Color Filler Treatment? (2020). Madison Reed:
  • Papanikolas, Christine. (2021). What Does Hair Filler Do? Matrix.