The general recommendation is to leave bleach on your hair for a maximum of about 30 minutes. Beyond this time, the risk of serious damage such as brittleness or scalp irritation increases significantly. The exact time depends on your hair type and color:
- Blonde or fine hair: 10 to 20 minutes
- Dark or coarse hair: up to 30 minutes, with some suggesting splitting the bleaching into multiple sessions for dark hair
- Very fine hair may need less time (10-15 minutes) since it processes faster
- Coarse hair may require up to 30 minutes, sometimes more than one application
Always monitor your hair and do a strand test to avoid over-processing. Leaving bleach on longer than 30 minutes is not recommended to prevent irreversible damage to your hair and scalp. If aiming for lighter shades, it is safer to do multiple bleaching sessions spaced apart rather than one long session.
