When hair disaster strikes, it's tempting to immediately do something to rectify the situation. However, undertake home hair dye removal with great care. Hair is a biological material and dyes are chemicals. Combining biology and chemistry is best done by a professional. Consult a licensed hair stylist for best results in repairing hair colour mistakes. Address the problem on your own only if that is impossible or impractical.
Understanding Hair Color
Your hair consists mainly of a protein called keratin. Keratin groups form a hair strand's body, or cortex. Another protein called melanin, located inside the hair shaft, provides hair with its colour; more melanin means darker hair. The hard cell cuticle, protecting the inner two layers, sits in shingle-like formations. Oils keep hair supple and strong. Water provides essential moisture, and its amount determines how porous a strand of hair will be.
Temporary and semi-permanent hair colours do not penetrate the hair. Instead, they coat its cuticle with small colour molecules, leaving the hair's internal structure intact. It typically lasts for six to 12 shampoos.
Permanent hair dyes, on the other hand, work chemically to penetrate the cuticle to change hair colour. They swell hair shafts, allowing peroxide or another bleaching agent to lift melanin out. At the same time, colour molecules move inside. These molecules form chains that are large enough to remain inside the hair shaft, resistant to removal.
Demi-permanent hair colours work mainly like semi-permanent colours, but do include a small amount of peroxide. Some colour will penetrate the cuticle, but these molecules do not form large chains, so they wash away after about 28 shampoos. Demi-permanent colours do not contain ingredients to lighten your natural hair colour.
Before attempting to remove or reduce the effects of hair dye, determine which kind of dye is present.
Removing Semi- and Demi-Permanent Color
Semi-permanent and demi-permanent hair dyes are conveniently designed to fade. Accelerate the process by washing your hair repeatedly with a strong shampoo, preferably one that is alkaline. Do not use a shampoo that is labelled safe for colour-treated hair; you do not want ingredients that protect those colour molecules. Shampoos such as Prell and Head & Shoulders reportedly work well, and even dish detergent can suffice in a pinch.
Apply a hot oil treatment, available at any drugstore, to further your efforts. These treatments effectively both moisturise hair and strip colour, since they penetrate the hair's cuticle.
Permanent Dye Removal
Your hair dye has already swollen your hair shafts, penetrated the cuticles, lifted out melanin, and inserted dye into the cortex. At this point, it's wise to exercise care to maintain your hair's healthy appearance. Try dye removal methods in order from least to most invasive.
Success in removing permanent dye depends on the hair's porosity. In the 48 hours immediately after dyeing, the cuticle remains slightly open, lending you the best possibility of fading the dye. Seize this opportunity to correct your colour using the least traumatic method available.
Begin with the advice above for removing semi- and demi-permanent colour, repeating as necessary. These methods are least likely to cause further damage. They may not remove all the dye, but it's possible that you will be satisfied with partial removal.
Do Not Bleach
It might seem easiest to examine your hair, determine that it's just too dark, and reach for the bleach. After all, bleach lightens hair. It does so at the expense of the cuticle, however, which always needs to be breached when colour moves in or out of the hair shaft.
When you applied permanent dye to your hair, you bleached your hair as part of the process. Unless you attempted to lighten your hair by many shades, the bleaching was minimal. Should you apply bleach to your hair now, you breach the cuticle a second time, leaving it even weaker than before. Also, you'd likely be able to find only a stronger bleaching agent than the original hair dye contained, risking far more damage.
Overbleached hair, with its ruined cuticles, becomes very porous. Porous hair stretches easily when wet, making it ripe for easy breakage by routine handling. It also does not accept new colour evenly, making any corrective colouring a risky proposition.
Repeated bleaching may also leave hair dull, limp, and brittle.
Chemical Dye Removers
If, at this point, you cannot or refuse to see a hair care professional, there is one last open option: chemicals.
Visit your local beauty supply store--or choose one online--to obtain a permanent hair colour remover. A popular, well-reviewed brand is One 'N Only Colorfix, by Jheri Redding.
These products penetrate the hair's cuticle, but instead of further bleaching, they shrink colour molecules, releasing them from the hair. They leave hair lacking some moisture and protein, which may be replaced by conditioning treatments.
Permanent hair removal products will not restore your natural hair colour. When you dyed your hair, you both bleached it and deposited colour. When the colour exits, what remains is the bleached version of your own hair. Depending on the level of bleaching achieved by the initial dye, your hair may be light brown, orange, or yellow.
You may choose to dye your hair again to cover the bleached tones, but be careful to choose a new dye that is lighter than your intended result. Your hair will be porous from all of this processing and will pick up new colour quickly and easily. Also, choose an ash-toned colour; a warm colour will enhance the orange tones that the bleach has left behind.