In summary: He stopped washing his hair with any products and started using just cold water, in an effort to help with his dandruff problem. Overall seems to have worked for him. Seemed mildly interesting to me.
Not actually NSFW, but I tagged it because the thumbnail is a close-up of some pretty severe dandruff, and there’s a few seconds of video in the middle where he shows the condition of his scalp before quitting shampoo. Just thought I’d mention, in case that makes you squeamish.
Co-washing only (washing with conditioner and skipping shampoo) is highly recommended for folks with extremely curly hair.
I tried it with my largely straight and thin hair and it was a disaster for me. But different hair textures require different solutions.
Re: “all the after-products” Again, different hair types require different solutions. A heat protectant product (applied on damp hair after washing and before drying and styling) is really important if you’re using heated styling tools for straightening or curling your hair. Even moreso if you’re also coloring your hair, which can make your hair more susceptible to heat-based damage. Additionally, for certain hair types and cuts, styling products are absolutely necessary to achieve the look you’re going for. My hair won’t hold a curl without adding product to it before styling.
As I say on another comment on this thread, my hairdresser does recommend that I shampoo twice on wash days to ensure I remove all the dirt/grease/styling product. Shampooing once (with my SLS-free shampoo) wasn’t getting my hair clean enough.
So yes, including after-care products in your routine may necessitate different cleaning steps compared to someone who isn’t using the same products. But again, what you are doing with your hair and the type of hair you have also influences the types of products that are valuable for you to use (shampoo, conditioner, and aftercare.)
All that said, claiming that haircare is all advertising “with a bit of social dynamics and zero science behind it” is misleading, uninformed, and incorrect. 😘
Since you sound like you want science, here’s an interview with a doctor of dermatology.