I used to use Nexxus Polydermic Reconstructor (aka the old Emergencee) every few weeks, that is now discontinued. I still have some left over, but I have switched to the Aphogee (2-step) to replace it. I don't follow the directions though. I stopped using it years ago due to the need to have it dry with heat, then going back in the shower to wash it out. I didn't like the stiff feeling it left my hair and was always paranoid the wrong move would cause my hair to snap before it was fully washed out.
So, I have been using it the way I did with Nexxus. lol. This way, I'm still getting some hardcore protein. It's been working fine so far. True test will be if it helps to stop the unbelievable shedding I've had from Selsun medicated shampoo.