It took a few days for me to see a difference as well. It is scary at first because you think you're losing more. While most of mine did not come out on the brush, I could count upwards of almost a hundred hairs every morning shower. As to theories of scalp stimulation, I really can't say if it has truly been dispelled or not since at least from an anecdote standpoint it worked for me and the Nizoral seems to support whatever I'm doing. One of the Nioxin products is supposed to increase blood flow the head as well, although that did not work for me. Who knows, it may depend on what type of hair loss you have. I have vortex, but not MPB, so that may make a difference. I will run it by the hair specialist next time I see her since she is the one with the degrees in this field. It could have been something specific to me, but that seems unlikely.