RDR, I don't want to harp on it, but the Burt's shampoo does have soy protein fairly high up on the ingredients list (and lists amino acids lower on the list). I'm not sure if any of the other ingredients are proteins, though. You might want to try a different shampoo and see if that makes a difference in your hair. The reviews for this one are terrible, but it might be because the people using it had the wrong hair properties for that shampoo. It seems that volumizing shampoos work well for people with fine hair that likes protein, but I could be wrong.
Burt's Bees Volumizing Pomegranate and Soy review
It's also difficult to isolate ingredients (to see which ones our hair does or doesn't like) when there are so many in each product and we use several products every time we wash our hair! I'm still in the beginning stages of figuring out which ingredients my hair likes. And it's all about balance, so I'm trying to read my hair better to see what it wants when.
DarkN: here's some info on hair porosity
. The test is to put a couple of strands of hair in water and if they sink after 2-5 minutes you have porous hair. If they don't sink, you have low porosity. Not sure where normal comes in...sinks after 20 minutes?? If your hair is chemically treated or colored, or you use heat, your hair might be highly porous or fairly porous. To fill in the holes from these processes, you'd need to do protein treatments (PTs), always followed by a deep conditioning treatment (DT). The protein and porosity forums have more info...