My hair is fine and normal to low porosity. I have found it loves protein. I thought I was protein sensitive at first, but I'm starting to suspect the straw-like reaction I had was from other ingredients (panthenol in particular). What makes you think you are protein sensitive?

I know my hair needs protein when it isn't as curly. A good indication is when it starts to droop when it is wet. It will feel mushy when wet, and also a little mushy when dry. My hair will also start to be frizzier when it's dry, but feel really soft to the touch.

I second the gelatin PT. It's the first PT I tried and my hair loves it. I follow with a deep treatment, which means I put an emollient-rich conditioner in my hair and leave it in for 30-60 min.

Also, naturallycurly.com is one of the few sites that says low porosity hair should steer away from protein. Fine hair tends to love protein.
2b/c, high density
fine, medium porosity, normal elasticity
loves protein, hates polyquats
still searching for HGs