I used to use Phyto. I have always been a no-lyer. It's so gentle, but still pretty effective at straightening.
I stopped, though because it's just too expensive to keep up. I switched to Mizani, and now Affirm. I like both & if you go to the salon for a relaxer, most salons carry Mizani and Affirm. The few salons that do carry Phyto charge a grip.