I'm so glad I took a chance on this. I have dirty blond hair that's fairly responsive to sunlight. My hair was more than 3 shades lighter when I lived in Colorado, but has darkened significantly since moving to Alaska. My darker natural hair color is frustrating since it looks “dirty” so easily. I have wavy-curly hair and try to follow the curly girl method, so I have been hesitant to try salon coloring treatments and ruin my texture. I used the baking soda + hydrogen peroxide DIY method for awhile. This was intermittently effective and definitely wrecked havoc on my texture for up to a week afterwards. Plus the application was messy and it irritated skin at my neck and hairline. I decided to try something pre-made and this was a lucky find. Its super easy to apply and my hair doesn't require a recovery mask afterwards. Because of my DIY treatments I only needed to lighten the top and under regions, so I just spray there, comb to distribute, and put my hair in a bun or clip for the day. Im not sure I would apply this when styling my hair down. I tried blow drying but prefer to apply on a sunny day and take the dogs for a long walk. After the first application I started to see results in a few hours and definitely by the next day. No mess, no crunch, no damage. Its definitely not a drastic change, and I suspect if your hair doesn't noticeably lighten with sunlight you might be disappointed. My only regret is not taking before and after photos. Its to be seen if there's damage from long-term use andhow often it needs to be reapplied. But so far great product and more than worth the price.