Here's why:
* Bleach is a chemical process: Bleach works by opening the hair cuticle and dissolving the natural pigment. The chemical reaction is what lightens the hair. Heat, like from a blow dryer, won't speed up the lightening process in a safe or effective way.
* Heat can damage bleached hair: Bleached hair is already weakened and more porous than untreated hair. Applying heat can make it even more brittle, dry, and prone to breakage.
* Uneven Results: Using a blow dryer to help bleach process would cause uneven results because it's impossible to make sure the heat is evenly dispersed throughout the hair.
Instead of using heat, follow these guidelines when bleaching your hair:
* Follow the manufacturer's instructions: Always read and follow the instructions that come with your bleach product.
* Strand test: Do a strand test before applying the bleach to your entire head. This will help you determine how long to leave the bleach on and how your hair will react.
* Use a low developer: A lower volume developer is gentler on your hair and will minimize damage.
* Monitor the bleaching process: Check your hair regularly while the bleach is processing.
* Rinse thoroughly: Rinse your hair thoroughly with cool water after bleaching.
* Deep condition: Use a deep conditioner to help restore moisture to your hair.
In summary, do not use heat on bleached hair. It's best to let the bleach do its work at room temperature and focus on proper aftercare to keep your hair healthy.