Profile of a young Asian woman with wavy blonde hair

If you’re wondering how to bleach black hair, that means you’re planning to do it at home. We'd be remiss if we didn’t tell you that going to a professional is still the best way to get your hair bleached. But if you must do it at home, there are certain precautions you can take to avoid botching it and getting the best blonde you can from a DIY treatment. 

Pre-Treatment Care

When doing DIY hair bleaching, keep in mind that ending up with a bad hair day is the least of your worries. Bleach contains harsh chemicals that, if handled wrong, can do a lot of damage to your hair and even cause chemical burns on your scalp. Moreover, bleaching dark hair is much more difficult than bleaching already light hair. 

If you recently dyed your hair, if it has split ends, or if your hair and scalp are very dry, it might be better to avoid bleach until it’s healthier. Start prepping your hair for bleaching at least two weeks before getting the treatment. Use a nourishing hair mask or conditioner every other day leading up to the treatment. Use TRESemmé Keratin Smooth KERA10 Smoothing Mask, expertly crafted with KERA10 Protein Complex that penetrates hair 10 layers deep. Leave it on for five minutes and rinse thoroughly.

A few days before the treatment, skip the shampoo and cleanse hair with TRESemmé Detox & Nourish Serum Conditioner, which refreshes hair with green tea and antioxidant serum. For an extra nourishing cleanse, use Dove Nourishing Secrets Hair Boost Ritual Conditioner, which boosts hair health with coneflower and white tea.

During Treatment

Sectioning hair is essential to applying bleach evenly.

Hair bleaching involves the removal of melanin embedded deep within the hair cuticle. Bleach does this by lifting the said cuticles and penetrating the hair shaft. According to the book Chemical and Physical Behavior of Human Hair, black and dark brown hair contains 95% eumelanin, which determines the darkness of hair color. Therefore, it may take several passes of bleach to fully lift the color from black hair, and the more sessions of bleaching, the more damaged your hair gets.

To bleach dark hair to blonde, you need 30 volume peroxide. You might be tempted to get 40 volume to lift the color faster, but for DIY, it’s better to be on the safe side. First, section your hair to apply the bleach evenly and avoid blotchiness. Start a centimeter from the scalp and go all the way to the tip. Make sure that every strand is covered before doing the next section. Cover your head with a processing scalp or fold foils over each section.

Make sure to check every five minutes and don’t leave the bleach in for more than 30 minutes. Allow your hair to rest for at least a week before bleaching again. 

Post-treatment Care

Use a purple conditioner to maintain the vibrance of your blonde hair and prevent brassiness.

Post-bleaching, you’ll want to give your hair lots of nourishment to prevent dryness. Apply a toner to avoid brassiness and to tame the look of bleached hair. For everyday care, use TRESemmé Pro-Color Series Blonde Brilliance Shampoo and TRESemmé Pro-Color Series Blonde Brilliance Conditioner. Specially formulated with purple conditioner formula and jojoba oil, these products use violet pigments to neutralize brassiness and preserve blonde shades longer. The nourishing formula also keeps hair smooth and brilliant and is suitable for daily use.

Follow these tips on how to bleach black hair with care to save yourself from a bad dye job and your hair from damage.