I've heard amazing reviews about this product, but i can't say i'm impressed. I have natural hair and i use straightener once per wash, so my hair is not the most damaged. It's not an easy way to use it: wash, dry, prepare mixture, apply on hair, isolate, heat 15 minutes, walk around another 15, wash again, dry again) - the effect it's not worth it, i have a hair mask that give me smooth, silky, easily brushed hair, and i put it on wet hair and keep it 3 minutes. Maybe 1 fill-up is not enough  for my long hair, i don't know. I guess it worth 4 stars, but i'll give it 3 - a lot of hype, that's why i've had very high expectations.