Reddit reviews Marvy Shampoo Brush and Scalp Invigorator

I had done a DIY of a scalp scrub last winter, and like your experience with the Ouai, and mine was similar, unless you separate your hair in sections and apply the scrub before the shower it is impossible to get to the scalp. If you have a beauty supply shop near you ( I am in the US) you can get this exact brush for about two bucks and it is a nice supplement if you are looking for scalp exfolitation https://www.amazon.com/Marvy-Shampoo-Brush-Scalp-Invigorator/dp/B0001I8ZT4

I have a shampoo brush that I use when I co-wash and I LOVE it. I distribute the co-wash over my scalp with my fingertips first and then I use this all over my scalp for a few minutes. I haven't experienced product buildup on my scalp so I can't speak to that specifically, but I co-wash once a week and I have a fair amount of dandruff that builds up between. I feel like the shampoo brush really helps break up all of the dandruff--my scalp is flake-free after I use it. I haven't experienced any damage.

This would be the time where I make my regular point about a human curry comb and mention that it is very useful for really massaging any sort of shampoo into one's scalp and also ridding one of those flakes that need a good scrubbing to remove.

Ever since I started using one of these whenever I wash my hair, even without shampoo or without special dandruff shampoo, I have seen nary a flake.

I do the same thing. I wait about a week in between washes, so it's really funny if I end up missing a spot, that spot of hair will have a totally different texture than the hair that got baking soda on it. Also, I just rub it all in with my fingertips - I don't use a comb, but I have short hair. I have been thinking about getting one of these, though.