The best.
I damaged my hair using a keratin shampoo for over a year and felt like I was doomed to have frizzy hair forever. My hair stylist recommended R+Co products and this conditioner has proven to be excellent for hair repair. I use it as a regular conditioner leaving on for 5 minutes once a week and as a mask once a week (leaving in for 10 minutes). In the past two months, my hair has literally gone from 70% frizz to 30% frizz, and I think it's just generally healing. I also use the air dry creme for a little extra smoothing. I highly recommend this duo.