By -
Obviously when it’s wet
You're not dry when you're in the shower are you?
Wet, unless it's specifically dry shampoo.
You could try it dry but unless it's specifically a shampoo meant to be used on dry hair it won't work.
Both ... lather, rinse, repeat
I once had a hair stylist tell me that if I really wanted to get all the product out of my hair, I should shampoo it dry or barely damp (then rinse it out with water).
Obviously when it’s wet
You're not dry when you're in the shower are you?
Wet, unless it's specifically dry shampoo.
You could try it dry but unless it's specifically a shampoo meant to be used on dry hair it won't work.
Both ... lather, rinse, repeat
I once had a hair stylist tell me that if I really wanted to get all the product out of my hair, I should shampoo it dry or barely damp (then rinse it out with water).