I had the same experience with Ren ad I don't have protein sensitivities at all. I don't know what it was about it, but my hair hated it. The only thing I could think of was the amodimethicone since I've found that my hair doesn't do well with silicones in cleansers or conditioners.

Modified CG since 11/5/11
CLEANSE: VO5 Vanilla Mint Tea Clarifying, DevaCare No-Poo, CHS Treatment Shampoo
RO: DevaCare One Condition, SS Caitlin's Conditioner, Mop Top Daily Conditioner
LI: SS Repairing Protein Treatment, CHS Silk Leave-In
STYLE: Re:Coil, Curl Keeper, Deva Ultra Defining Gel, Curls Rock Amplifier and Strong Hold Mousse, Sweet Curls Elixirs Okra Gel and Hard Hold Gel, SS Curl Enhancing Jelly and Firm Hold Gel