If needed, it is better to Bleach over multiple sessions rather than more than 45 minutes at a time.
Make sure you heed the recommendations and directions on the pack.
Oh! Tip: Lightning Kit
The At Home Hair Bleach Kit is the perfect prelightening canvas for Semi Permanent Hair Color. Infused with bond-protecting Plex 2.Oh!, enriched with Argan Oil, and featuring Comfort Fragrance Technology, it offers a worry-free bleaching experience, creating the perfect canvas for our semi-permanent hair colors allowing you to embrace a spectrum of your dreams without fear.