Yes if you have brown hair that you want to be lightened then using purple shampoo on your hair can help to lighten the hair color.
I have successfully used purple shampoo on my brown hair to lighten it and it did eventually lighten my brown hair after a few months of washing my hair with purple shampoo.
Purple shampoo also rid your hair of any brassy tones by way of depositing blue and violet pigment and cool shades.
Use the purple shampoo on your hair every few days or 3 times per week to see the brown hair lighten to the way you want.
Wet your hair and then apply the purple shampoo and scrub it in and let it sit for 5 to 20 minutes and then wash it out like normal.
You can also use coconut oil to help give your hair a nice shiny light color if you warm some coconut oil up and then leave it in your hair overnight while wearing a shower cap.
Then wash the coconut oil out of your hair in the morning.